This report summarises the finding of 48 meta-analyses on the most effective ways individuals can improve their own subjective wellbeing. Through this review, we found that mindfulness, the Best Possible Self intervention, and compassion interventions were among the most effective interventions. This article collects a wealth of advice and resources, so we suggest you read the summary and then focus on exploring what seems most useful to you. Note that a substantially modified version of this article is scheduled for publication in the upcoming edition of the journal Flourish.

Summary

• This Effective Self-Help report is intended to help you improve your subjective wellbeing (SWB), by sharing key actionable findings from happiness research, and presenting you a ranked list of the best interventions you can follow to be happier.
   
• We start with a general discussion on improving SWB to give an overview of some of the most effective ways to improve it.
  • What we mean by subjective wellbeing is “the extent to which a person believes or feels that their life is going well, from the perspective of their own evaluation of the quality of their life”.
  • High levels of SWB are associated with better health, relationships, work performance, and fewer mental health problems.
  • A few broad factors seem particularly important to explain how happy we are: genetic predispositions, fulfilment of fundamental physical, psychological and social needs, and living in a prosperous community. More specifically, it matters a lot for SWB to have good physical health, no mental health problems, as well as having satisfying employment and intimate relationships.
     
• While this article focuses less on them directly, we consider the following broad general recommendations for improving your SWB to be of primary importance: 1) take care of your mental health, 2) develop a healthy lifestyle, 3) build positive relationships, and 4) focus on making progress on well-chosen goals.
   
• Our research methodology, of which we give a detailed account further down, led us to review 48 meta-analyses and systematic reviews on the effectiveness of 20 different happiness interventions.
   
• After some brief advice on how to implement them, we describe the 20 interventions, that we divided in four categories based on their promisingness and evidence base:
  • The most promising interventions with a strong evidence base we found are Mindfulness, the Best Possible Self intervention, Compassion interventions, Physical activity, and Multi-component Positive Psychology Interventions.
  • Interventions we view as promising and with a strong evidence base but a smaller effect size are Using character strengths, Acts of kindness, Gratitude, Singular Positive Psychology interventions, Acceptance and Commitment Therapy (ACT) and Cognitive-Behavioral Therapy (CBT).
  • We view Leisure, Sleep, Contact with nature, Yoga and Expressive writing as the most promising interventions with a weaker evidence base.
  • Lastly, we conclude that Forgiveness interventions, Reminiscence interventions and Pleasurable experiences are promising interventions with a weaker evidence base and a smaller effect size.

Introduction

Being happier can have numerous benefits for your health and productivity, in addition to being valuable in itself. We reviewed 20 interventions across 48 meta-analyses and systematic reviews, and found that practising mindfulness meditation, following the Best Possible Self intervention, and compassion interventions are among the most promising ways to increase subjective wellbeing (SWB).

We focus on directly testable interventions. These are usually short-term and generic, in the sense that they are not tailored to your specific situation: most of these interventions are one-size-fits-all and tested on the general population. There are obviously many ways to improve your SWB that fall outside this scope, so we encourage you to take a longer-term perspective too and consider your own life circumstances.

This report was produced by Effective Self-Help, an EA organisation researching the most effective interventions for improving wellbeing and productivity. The recommendations discussed below should help you feel more satisfied with your life and experience positive moods in your daily life.

Effective Self-Help has previously conducted research into sleep, stress and habit formation interventions, and compiled a database of productivity recommendations; these reports can be found on our website. For a more in-depth explanation of ESH’s aims and strategy, we suggest reading this article.

If you’re short on time, we suggest you to directly consult the section Discussion of Interventions, and then the section Improving subjective wellbeing: a general discussion. In an attempt to maintain its level of rigour and keep it fairly dense, this article is heavy in footnotes, which often give more information on the cited studies and allow for a deeper dive into the content.

Important note: Persistent low mood can be the sign of an underlying mental health issue that should take precedence and may require professional support.

Summary of our findings

The summary table below offers a concise overview of our top five findings, ranked in order of effect size. For a more comprehensive background to these results, including links to each study we reviewed, please see our evidence spreadsheet.

Improving subjective wellbeing: a general discussion

Research on wellbeing is a vast area of study, covered primarily by psychology as well as economics, with more than 55,000 new publications each year.^[1] It is thus only possible here to give a very brief summary of some of the most important or useful findings, with a focus on the benefits of SWB and its predictors. We recommend this Nature review article for a broad, high-level and recent overview of key areas and conclusions in SWB research, and it is from this that we draw a lot of the information in this section. Alternatively, the Handbook of Well-being provides an in-depth overview of the area, including numerous research discoveries relevant to improving one’s own wellbeing.^[2]

What do we mean by subjective wellbeing?

In the academic literature, subjective wellbeing generally refers to the extent to which a person believes or feels that their life is going well, from the perspective of their own evaluation of the quality of their life.^[3]

Researchers often distinguish the evaluative (or cognitive) dimension of SWB, typically assessed by people’s appraisal of their satisfaction with life, from its experiential (or affective) one, referring to moment to moment wellbeing, as reflected by frequent positive affect and infrequent negative affect. SWB can itself be contrasted with psychological wellbeing (or sometimes more broadly eudaimonic wellbeing), the latter being defined as desirable psychological characteristics such as autonomy, environmental mastery, personal growth, personal relationships, purpose in life, and self-acceptance.^[4]

Although it may depend on how one precisely defines it, happiness is frequently considered to simply be the colloquial or popular term for SWB.^[5]

For an introductory discussion on the measurement of wellbeing, see this report by the Happier Lives Institute, as well as the review paper by Diener et al. (2018b) and their Table 1 in particular for a definition of the main terms related to wellbeing used in research.^[6]

In this report, we focus predominantly on SWB, as opposed to psychological wellbeing, in large part because it is from this stream of research that we found the most evidence, which may reflect a higher level of interest among researchers. The section The choice of which wellbeing outcomes to use gives more details on our choice of wellbeing measures for evaluating interventions.

The relevance of focusing on your subjective wellbeing

Existing EA discussion

There has already been substantial quality discussion within the EA community and on LessWrong on ways to improve one’s wellbeing, at a minimum reflecting notable interest from EAs on the topic. Several tags gather relevant posts on the EA Forum and LessWrong (whether specifically on improving one’s own wellbeing or more broadly). Three particularly prominent articles reviewed some wellbeing research to give practical advice: the section Apply scientific research into happiness from the self-help chapter of 80,000 Hours’ 2017 career guide, How to be happy by Luke Muehlhauser and Be happier by a now anonymous author.
 

The benefits of being happy

Even though the value of taking action to feel happier should be self-explanatory, let us nevertheless present a wealth of research that has linked high SWB to positive outcomes in various dimensions of life. Some of the findings with the strongest evidence base^[7] are the following:

• SWB positively influences health and longevity,^[8] probably in large part through effects on health behaviours and on the cardiovascular and immune systems.
   
• Feeling happy leads to better social relationships,^[9] whether with friends, romantic partners, at work or in terms of broader civic engagement.^[10]
   
• Higher life satisfaction and positive affect are associated with better work performance.^[11] This can be explained through the influence of SWB on the health, absenteeism, self-regulation, motivation, creativity, relationships, and job turnover, all of them being outcomes for which wellbeing is beneficial.
   
• Although the evidence base seems weaker for this aspect, good levels of wellbeing and positive emotions can be viewed as a buffer against mental health problems and an important contributor to resilience.^[12] For instance, happy people likely recover quicker from stressful events,^[13] are protected against the negative effects of stress,^[14] and have a lower likelihood of developing a mental illness.^[15]

So on top of being an obvious intrinsic goal for most people, viewing it as “extremely important”,^[16] happiness appears to be beneficial across many areas of life. There is some debate around the optimal level of SWB,^[17] since, for example, “for achievement activities such as earning high college grades and high income, moderately high SWB was optimal, and above that there was a small falling-off”, and since “momentary negative emotions can in some instances be helpful”.^[18] It is also worth noting that a substantial part of this cited research is non-experimental, which should make us more uncertain about whether improving your wellbeing will directly result in these benefits.
 

A focus on wellbeing is probably not the best way to make progress towards other goals

Despite these substantial benefits, it’s worth keeping in mind that it would be surprising if the best interventions specifically targeted at improving wellbeing also happened to be the best for close but distinct objectives, such as alleviating a specific mental illness, like reducing depression.

In particular, if you suffer from a mental health problem that you want to deal with, it probably makes more sense to try to tackle the issue directly rather than using “improving SWB” as a proxy goal. For more guidance in this direction, see for instance the Resources page from the EA Mental Health Navigator.

Similarly, the best strategies to feel happier aren’t necessarily the same as the best ones to increase your productivity, even if the gap between the two goals is probably smaller than is sometimes assumed.

With that said, the following points apply in relation to mental health:

1. We haven’t methodically collected the evidence for this, but at least some of our recommended interventions for improving SWB also have a positive effect on conditions like depression and anxiety. As an illustration, van Agteren et al. (2021)^[19] are encouraging healthcare practitioners to integrate wellbeing enhancing interventions in their treatment of mental illnesses.
    
2. It has been argued, with some empirical support, that if we view the entire distribution of a population’s mental health as a continuum, then, shifting the population mean upwards (with e.g. happiness interventions) should be associated with a significant reduction in the prevalence of common mental disorders.^[20] In this view, an EA community with a higher SWB would likely have fewer members affected by mental health problems.

What determines our happiness?

Providing anything close to a comprehensive summary of the factors that play an influential role in determining our level of SWB - its determinants, or correlates - is beyond the scope of this report.^[21] We can however point to some major results found in the literature, as well as provide a sense of their relative importance in explaining why our wellbeing is at a certain level.

Firstly, genetic predispositions play an important role in explaining the differences in SWB between individuals.^[22] Estimates from heritability studies indicate that about 30 to 40% of this variance in SWB is due to genetic factors. While significant, this still leaves about 60 to 70% of SWB attributable to environmental effects, emphasising the value of thoughtful life choices and actions. This view is defended in greater detail in Sheldon and Lyubomirsky (2019).

Secondly, the fulfilment of some fundamental human “needs” seems conducive to high levels of SWB: Diener and Tay (2011) found, from a large survey covering all sociocultural regions of the world, that having universal needs met was consistently associated with SWB. They conceptualised and examined six needs: (1) basic needs for food and shelter, (2) safety and security, (3) social support and love, (4) feeling respected and pride in activities, (5) mastery, (6) autonomy and self-direction. Among them, life satisfaction was most strongly associated with basic and social needs, positive emotions with respect and social needs, and negative feelings with respect and autonomy needs.

Sheldon and Lyubomirsky (2019) suggest in their proposed Positive Activity Model that psychological need satisfaction is one mechanism through which positive practices and activities (such as the interventions we discuss in this article) work to boost wellbeing. For instance, the benefits of expressing gratitude may partly come from an increase in social connectedness, since sharing grateful thoughts and feelings helps form deeper bonds.

Thirdly, several community and societal factors are associated with SWB, such as living in a country with lower inequality and corruption, more political freedoms, as well as in a less polluted area and near green spaces.^[23] As for the role of economic factors, robust evidence shows that national income is strongly associated with SWB,^[24] but note that there is considerable discussion and debate on this topic - including, but not limited to, the famous Easterlin paradox^[25] - which we won’t go into here.^[26] This 80,000 Hours article from 2016 reviews some evidence on personal income and happiness (in the context of career choice, they write: “We think the message is clear: if you want a satisfying career, once you’re earning above about $40,000, don’t focus on earning more money.”, and see their section How much does income matter relative to other factors?). This more recent EA Forum article reviews new research on the same topic.

Fourthly, specific personal life circumstances do have an influence on SWB, with changes in some of them producing lasting changes (see just below for more details on the importance of various life circumstances). While people on average adapt to marriage after some time and having children isn’t associated with higher SWB, becoming a widow, unemployed, or disabled is linked to lower SWB for a longer term.^[27]

Among these different needs, life circumstances and socioeconomic factors, which ones play the biggest role on average in determining people’s life satisfaction?

To answer this question, Frijters et al. (2020) used cross-sectional data from the representative British Household Panel Survey.^[28] They estimated the fraction of the variance of adult life satisfaction explained by different socioeconomic factors,^[29] or in simpler terms the most influential happiness factors.

The factors they included explained only 19% of the total variation, so many other factors were left out. Among the factors they identified, the most influential one was health : mental health - in this case being diagnosed with depression or anxiety - explained a considerable 46% of the fraction of the variance, and physical health explained 15%. This was followed by social connections factors, namely having a partner (15%), being employed (8%), and income (10%).^[30]

Frijters et al. (2020) also compiled a list of effects on life satisfaction of various individual circumstances and policy changes (their Table 1). It is originally presented as an aid for political decision-making and the evidence base is mostly not directly experimental, their results mainly coming from observational studies or natural experiments. Yet it can still be useful to get a first sense of the magnitude of variation in life satisfaction we can expect from several personal life changes (which are not the same as our reviewed interventions).

The changes with the highest effect^[31] on life satisfaction, with “(+)” for positive effect and “(-)” for a negative one, were, in decreasing order: going from healthy to a poor physical health (-), going from depression to full mental health (+), going from employed to unemployed (-), going from unemployed to the out-of-labour force (+), going from partnered to separated (-), being a victim of a violent crime (-) and doubling one’s household income (+).

Geerling and Diener (2020) also used survey data to get insight into what factors contribute more or less to SWB. The data comes from the large Gallup World Poll, which includes a representative sample of adults from 166 nations. They calculated the “percent range”, i.e. the difference between the highest and lowest point, of three SWB scales - life satisfaction, positive affect and negative affect - covered by groups of different factors.

The factors that covered the highest percentage range for life satisfaction were nationality with 45% (i.e. 45% of the life satisfaction scale was covered by differences between the most extreme nations in terms of life satisfaction), followed by income, social support, basic needs and health satisfaction. The most influential factors, in this specific sense, for positive affect were social support, nationality, health satisfaction and income. For negative affect, nationality, social support, health satisfaction and health problems were most influential.^[32]

Broad recommendations

In addition to the interventions we reviewed in more detail and present in the section of the report on the best interventions, we propose here a few broad recommendations that we think it makes sense to follow or keep in mind if you want to improve your wellbeing. They differ from the reviewed interventions in one or both of these two dimensions:

1) They are wider and less targeted. The wellbeing interventions we reviewed are mostly about specific and directly testable methods or procedures, often that you can follow for a limited period. Instead, the advice just below should be seen as general guidelines helpful for setting up a solid basis for a happy life.

2) We applied a different standard for the evidence base. Even though we tried to ensure that the advice in this section rests on the most solid and recent evidence, it is not exclusively based on meta-analyses of experimental studies, but also on non-experimental data and individual randomised control trials (RCTs), many of which have been mentioned in the preceding section. Furthermore, the criteria we used for the ordering of these broad recommendations are looser.^[33] Roughly speaking, they encompass: (a) how broadly applicable the recommendation is, (b) how strong the evidence (taking into account indications of magnitude of effect) is, and (c) how well it aligns with the sensible advice commonly given by high-quality sources, as well as experts’ views.^[34]

Here we will only cover the basics, but we recommend you explore these cited sources for more details and application tips. None of these ideas are surprising, yet it can be valuable to be reminded of the most notable ones and receive confirmation of their evidence base.
 

Take care of your mental health

Since “the biggest single predictor of individual happiness is mental health”,^[35] taking steps towards the diagnosis and (professionally supported) treatment of potential mental health conditions or difficulties you may have is likely to be a highly worthwhile endeavour for your SWB. As written above, even if you might find suggestions among our recommendations useful, it would probably be best to follow the specific recommendations for the mental health issue you might be struggling with. In addition to the EA Mental Health Navigator, official guidelines from trustworthy institutions like the NHS offer a good place to start.
 

Develop a healthy lifestyle

This is pretty evident, but it can be easy to start thinking that the solution for a higher life satisfaction and more positive emotions lie in complicated changes, when in fact relatively simple improvements in lifestyle and health habits would already have a great effect. Regular physical activity, a healthy diet^[36] (including the obvious eating more fruits and vegetables)^[37], sufficient quality sleep, and limited consumption of harmful substances form the basis of good physical health and its preservation,^[38] which has a strong influence on SWB, as we mentioned above. Developing such healthy habits is likely to produce significant improvements to your wellbeing.^[39] While beyond the scope of this report, we hope further research will enable us to better differentiate the relative value of these different lifestyle changes and the best approaches available.
 

Build positive relationships

Across the evidence we reviewed, quality social relationships were consistently highlighted as an essential ingredient of high SWB.^[40] Beyond obvious actions like spending enjoyable time with friends and family, the following suggestions can give you some ideas to develop satisfying social bonds and sustain or strengthen existing ones:

• Join a social group, such as through involvement with an EA group, or consider volunteering, with a focus on the social connections and satisfaction it brings rather than the impact accrued.
• Improve your social skills.^[41]
• Learn to respond enthusiastically^[42] to good news shared by your close ones, as it is associated^[43] with several benefits, like greater positive emotions and relationship satisfaction for both people in the interaction.

You can find basic advice on “social wellness” on the NIH website, and on intimate relationships on the NHS-recommended website of the charity Relate (see also this NHS page on relationships advice) .
 

Overarching advice: focus on making progress on well-chosen goals

As goal progress has been significantly associated with SWB at the meta-analytical level,^[44] working towards important goals you may have can by itself provide benefits to your happiness, in addition to the direct benefits you get from goal advancement.

To get the most out of goal striving in terms of SWB, and mainly based on two literature^[45] reviews on the topic, we advise you to, in order of importance:

1) Focus on the process of goal pursuit, i.e. the progress you’re making, rather than on the desired outcomes of the goal - in other words, the means to pursue the goals (“running”), not the ends (“better endurance”).^[46]

2) Choose autonomously selected (or generated)^[47] self-concordant goals, namely goals that you believe are intrinsically important to have and that bring you fun and enjoyment, rather than ones pursued only because of external pressure or coercion.^[48]

3) Choose approach and not avoidance goals.^[49] 

4) Choose goals aimed at satisfying psychological needs (in particular affective needs), feelings and implicit motives such as autonomy, competence, social relatedness and self-acceptance, rather than extrinsic goals like an appealing appearance or financial success.^[50] 

5) Stick to realistically attainable goals given your resources that won’t conflict too hard with your other goals (e.g. allowing you to find balance in your activities) and from which you’re ready to disengage in cases where their pursuit becomes too costly or less relevant.^[51]

Having said that, you can use the various recommendations in this article to devise happiness conducive goals, such as developing physical and mental health positive habits, taking steps for a more fulfilling social life or following our recommended interventions. Note however that some findings indicate that explicitly striving for SWB directly does not work well.^[52] This leads Sheldon and Lyubomirsky (2019) to rather recommend a focus on “eudaimonic” type activities (i.e. growth-promoting and intentional goals and behaviours, focused on long-term self-improvement and connections with others) which tend to bring SWB as a kind of side effect.^[53] 

As for goals concerning a change in your life circumstances, let us stress two points. First, it can be useful to keep in mind the relative influence of various life circumstances, in order to focus on the ones that are most important^[54] and less prone to adaptation.^[55] Second, such a focus might not be the most cost-effective way to sustainably increase your SWB.^[56]

Notes on our methods

Overview of our research process
 

We reviewed 48 meta-analyses and systematic reviews on the effectiveness of different happiness interventions. For each of the 20 interventions we studied, we compiled information mainly on: (a) the size of effect (Hedge's g or Cohen's d), (b) the number of individual studies and (c) when available, the total number of participants in the meta-analysis, (d) the population group, and (e) the measure of wellbeing used in each paper. You can find this information and many precisions on these criteria in the Data sheet of our Evidence Table.

After this compilation, we synthesised the evidence for each intervention in the Results sheet, including a consistency assessment, a rough judgement of time efficiency and an average effect size on which we based our general ranking. Detailed accounts of the interventions as found in the reviewed studies were also compiled in our Descriptions of interventions sheet.

Effective Self-Help strives for a very high degree of reasoning transparency and rigour in producing our findings as these are characteristics that are too often lacking from self-help literature. Given this, we encourage you to review our evidence and how we compiled it for yourself.

For further information on how we conduct our research, what methods we use, and why we use them, please see our website.
 

Details on various aspects of the process

Finding interventions and studies to review

The interventions we reviewed were all in the category of psychological or behavioural interventions, that we can define as “activities or group of activities aimed to change behaviours, feelings, and emotional states”.^[57] We restricted ourselves to directly testable and time-limited interventions tailored to individuals, that had been the subject of RCTs assessed in at least one meta-analysis. Our ranking process therefore didn’t focus on interventions at the collective or societal level, or an in-depth examination and ranking of the most important factors for happiness, a topic we nonetheless covered above.

We started by looking for interventions that we could evaluate in recent papers providing broad overviews or listing many interventions such as van Agteren et al. (2021),^[58] Carr et al. (2021), Koydemir et al. (2021), Donaldson et al. (2021) or Diener and Biswas-Diener (2019). For each intervention, we then searched for the highest quality recent meta-analyses and systematic reviews. We aimed to be methodic in our search process, by for instance systematically looking at the first three pages of the Google Scholar results for some variation of the string “[intervention name] wellbeing meta-analysis”. We also ended up using a lot Elicit and Connected Papers to navigate through the literature in search of the most relevant papers and meta-analyses. For each paper, we made a subjective but informed assessment on whether to include it or not, based on criteria such as the studied population (i.e. how close it was from the general non-clinical population), the wellbeing outcome measured or whether it was likely made redundant by subsequent papers.^[59]
 

Our use of effect sizes

The central information we took out from each reviewed meta-analysis was the effect size, mostly as Hedge’s g, but also as Cohen’s d, or in rare cases as a correlation coefficient that we converted to Cohen’s d. Hedge’s g and Cohen’s d, also known as standardised mean differences, are extremely similar.^[60] They give us the difference between the wellbeing outcome of the intervention group and the wellbeing outcome of the control group, adjusted for the wellbeing scale.^[61] This allows us to compare the effects taken from different scales into a similar reference frame.^[62] The conventional interpretation is that values of 0.2-0.5 are considered small, values of 0.5-0.8 are considered medium, and values above 0.8 are considered large.^[63] You can check this great interactive tool for a visualisation and simple explanation on how to interpret Cohen’s d.^[64]

In some instances in our review process, we encountered several potential effect sizes that we could extract from the same meta-analysis, and had to choose only one of them for the specific intervention in question. We reasoned then on a case by case basis to select the one that seemed most relevant to our intervention recommendation purpose, taking into account factors such as the wellbeing outcome measured,^[65] the comparison group,^[66] the time of measurement^[67] and the number of involved participants.^[68]

The choice of which wellbeing outcomes to use

While carrying out our research we came to realise that a large variety of wellbeing measures were used across studies. Yet is it reasonable to proceed as we did in compiling then aggregating into a single result numerous different measures or scales, sometimes markedly dissimilar?

On the one hand, many researchers argue for or present evidence in favour of the conceptualisation of the various potential dimensions of wellbeing as a single overarching construct.^[69] Moreover, we’ve encountered countless cases of aggregation of different measures into a single effect size, which appears to be a standard practice.^[70]

On the other hand, some evidence does not support the validity of a complete merging of the distinct happiness constructs,^[71] and measures are sometimes deemed too heterogenous by researchers to aggregate them.^[72]

Overall, we think that since it allows us to include much more data into our results, such a combination remains a sensible approach, as long as we keep in mind that the assertion “this intervention has been shown to improve subjective wellbeing” can mean non-trivially different things when we examine the details.

But what measures did we favour including when we had the choice? Following recommendations found in the literature and taking into account the prevalence of certain measures,^[73] we preferred life satisfaction then positive and negative affect.

Calculation of an overarching effect size

After the compilation of all the individual studies information in our Data sheet, we aimed to calculate an “overarching” effect size for each intervention.

We considered several options for the overarching calculation:

a) Calculating the mean of all effect sizes weighted by the numbers of studies included.^[74]

b) Calculating the unweighted mean of all effect sizes.

c) Calculating the mean of all effect sizes weighted by the inverse of the confidence interval square.^[75]

d) Only taking the effect size of the highest quality meta-analysis.
 

After some internal and external discussion, we opted for option a), which seemed to be a satisfying compromise between a reasonable weighting of the evidence (i.e. taking into account the “statistical quality” of the results) and legibility.^[76] At any rate, our methods don’t constitute a bulletproof (meta-)aggregation process, but should rather serve as a solid heuristic to head towards the very best interventions.

Time efficiency

Although we want to stress that we think you shouldn’t put too much weight on them, we also calculated time efficiency scores for each intervention. To do that, we first searched through the meta-analyses and sometimes their included studies themselves to find descriptions of the duration of interventions as tested in the studies, which we listed in the Descriptions of interventions sheet as a range between the shortest and longest duration. We then divided the middle of the range by the “overarching” effect size of the intervention to calculate a score. This time efficiency score is best interpreted as a rough indication of the time you need to invest to get to a certain level of results.^[77] But it loses some of its meaning when interventions start being practised on a regular basis as habits, as the time commitment becomes stable - not only a one-off endeavour - and it’s unclear what happens to the initial boost all else equal.

Categories for the interventions

Though we kept the ranking in terms of effect size for both of them, we separated the interventions into two subsets: the interventions with a strong evidence base and the interventions with a weaker evidence base. To belong to the strong evidence base category and not be downgraded to the weaker evidence base category, an intervention had to meet these four criteria: (1) the total number of included studies across meta-analyses had to be 10 or above,^[78] (2) the effect size had to be mostly standardised mean differences and not correlation coefficients, (3) the population had to be mostly non-clinical adults in the majority of meta-analyses, and (4) the wellbeing outcomes measured had to be mostly life satisfaction, positive or negative affect, or another established wellbeing scale,^[79] and not close but distinct measures like mental illness, stress or quality of life, in the majority of meta-analyses. For both of these categories we further splitted interventions according to their higher or lower effect size.

Selection of resources for practising the interventions

For each intervention, we searched for empirically supported and quality self-help resources to recommend, like books, apps, or online programs. We followed roughly the process below:

1) Look, directly in all the meta-analyses reviewed for the intervention, for relevant RCTs evaluating wellbeing with one of the words “self-help”, “online”, “web”, “internet”, “book”, “app” in their title.

2) Check inside each of the selected RCTs whether there is a usable resource to link to or describe.

3) Check the EA Forum, LessWrong and then other sites like 80,000 Hours, the NHS and Greater Good in Action to find resources that seemed good and close to what the studies evaluated.

4) Sometimes conduct a broader online search, with a focus on how close the resources are to what the studies evaluated, and how popular or recognized they seem to be.

In general, we would have liked to find more resources with direct empirical support, and it’s still quite possible that we missed some very good ones.

Limitations of our research

The aim of our research is to produce rigorous quality results on which we can base our recommendations. However, it’s worth noting that there are several limitations worth keeping in mind, in particular to avoid over-interpreting the results.
 

First, note that, while we strived to follow a methodical and transparent research process, we still had to make many judgement calls. For instance, the choices of which effect size to select among several wasn’t always straightforward, as well as which meta-analyses to include or not. As much as possible, we tried to explicitly state the reasons for our decisions (e.g. in the notes of the Evidence table), but one should be aware that we unavoidably relied on several subjective assessments.
 

Second, our classification of interventions is somewhat debatable. Coming up with coherent categories for interventions wasn’t too hard in many cases, but we came across difficulties in a few instances. For example, even if compassion and mindfulness/meditation interventions are clearly distinct as a whole, we found out that the sub-intervention mindful self-compassion had been included in either of these two interventions, depending on the meta-analyses.^[80] More generally, it occurred to us that protocols of interventions in theory distinct commonly overlapped.^[81]
 

Third, the reviewed meta-analyses also overlap in terms of the individual RCTs they include. For instance, we counted that, for the Best Possible Self intervention, 10 out of the 16 RCTs included in van Agteren et al. (2021) had already been included in Heekerens and Eid (2021) (which itself included 34 RCTs in total).^[82] In hindsight, it was maybe a bit redundant to review so many meta-analyses. Nonetheless, the inclusion of several ones is a way to smooth out their differences in effect sizes and arguably increase the robustness of results.
 

Fourth, as we mentioned in the section The choices of wellbeing outcomes, a combination of this many measures - or sometimes only proxies - of wellbeing, makes the interpretation of our results more equivocal.^[83] It’s therefore wise to go check the Evidence table to see in detail the outcome tested in each study.
 

Fifth, we could have included even more information in the Data sheet, such as details on the control group type (e.g. active or passive), a measure of heterogeneity, of publication bias, or follow-up information more methodically collected when it was available (but it most often was not).^[84]
 

Sixth, we reviewed studies mostly focused on non-clinical participants from WEIRD cultures,^[85] which casts some doubts on the broad generalizability of the results. The farther you are from this type of demographics, the less you should give weight to our findings for yourself, although they probably should still remain quite informative. If you suffer from a clinical condition (whether mental or physical), you can check Table 3 of van Agteren et al. (2021) for effects on wellbeing of various interventions on mentally and physically ill populations, as well as Chakhssi et al. (2018).^[86] We also came across papers of interest on interventions on non-western populations and on sexual and gender minorities.
 

Seventh, keep in mind that our “overarching” effect size calculation process, on which our ranking of interventions is mostly based,^[87] should best be seen as a sort of heuristic way of approximating a global meta-analytical effect size, and not as the result of a more advanced statistical analysis.
 

Eighth, features of current psychological research itself, in particular on happiness interventions, can lead us to question the strength of our recommendations. Several researchers mention the limited evidence quality and field maturity in wellbeing interventions research.^[88] In addition, it’s possible that the dodo bird verdict applies to happiness interventions stemming from positive psychology, which is the claim originally pertaining to psychotherapies that all forms of treatments yield roughly equivalent outcomes regardless of their specific components.^[89] Finally, psychology’s replication crisis should lead us to generally take empirical findings from psychological experiments with caution, with meta-analyses suffering from publication bias and selective reporting,^[90] leading to a potential substantial overestimation of effect sizes by a factor of three.
 

Ninth, there might be a gap in effectiveness between the interventions as tested in the reviewed studies and the way we’re assuming you’re mostly going to follow them, that is as (self-)guided self-help. As you can see in the Description of interventions sheet, the modes of administration were diverse, but the self-guided format is sometimes considered less effective.^[91]
 

Discussion of Interventions
 

Suggestions on how to implement our advice on interventions

It turns out that a large majority of our reviewed interventions have effect sizes in the “small” range, with large overlaps in the confidence intervals reported among the individual meta-analyses.^[92] We want to emphasise the importance of personal fit for the successful implementation of any of these interventions. Indeed, although it can be really useful to direct readers preferentially to the most promising ones at the collective level, the concordance between the activity and yourself is arguably a central factor of intervention individual effectiveness.^[93] You may also find this comment by David Althaus on interindividual effectiveness variability and self-experimentation useful.

So we suggest you adopt an open-minded and curious approach towards the ranked list of interventions, by trying out several of them, even for a brief moment, with a priority given to the ones at the top. Then you can select the one(s) you want to pursue further, based on personal appeal and sense of effectiveness.^[94] A particularly judicious one to start with would be a Multi-component Positive Psychology intervention, as practising the various exercises it contains would allow you to try out several others of our listed interventions. And generally, mixing elements from the different interventions seems relevant if you find ways to do it.

As for the way to select the specific resource you want to use for an intervention, personal preferences should also probably be one of your main decisive factors. We erred on the side of listing many options, so that you can choose yourself which one is most appealing. A basic process is to at least have a glance at several of the resources you think may suit you before committing to one of them. But we still tried to give a sense of how solid the recommendation is in the way we present each resource, and in most cases you can treat the order in which they are mentioned as an indication of how relevant they seemed to us.
 

What are the best ways to sustain the happiness boosts you may get from following some of these interventions for a certain amount of time?

Our answer to this large question is that it’s not entirely clear. We’ll just refer again to the models presented in Sheldon and Lyubomirsky (2019), as well as to Ng (2015),^[95] to suggest that a fruitful approach might be both to invest continued and sustained effort in these activities, and to practise the interventions in a varied and changing manner (not in the exact same way each time). It can also be beneficial to combine interventions, such as by doing physical activity in a natural setting.^[96] Lastly, if you want to develop happiness practices as everyday life habits, you might do well to start by an initial relatively intense practice of an intervention (e.g. for a month) to pick it up more solidly.^[97]

Discussion of the Most promising interventions with a strong evidence base

Mindfulness/Meditation interventions

Size of effect: 0.39

Intervention: Practising meditation regularly, using techniques such as body scan and diaphragmatic breathing.
 

Meditation and mindfulness practices appear to be particularly effective methods for improving subjective wellbeing. Mindfulness can be defined as a mode of awareness characterised by nonjudgment, acceptance, and a present-moment focus, all of which can be developed through mindfulness meditation practice.^[98] This type of intervention can be beneficial for your SWB, in that trained and improved awareness can give you more choice in how you relate and respond to your subjective experience, rather than automatically responding in more unhelpful ways.^[99]

Meditation and mindfulness can be practised in a high variety of ways, such as through a Mindfulness-Based Stress Reduction (MBSR) or a Mindfulness-Based Cognitive Therapy (MBCT) program,^[100] and in diverse formats, like with an app, a face-to-face practice group, following instructions from a book, or at an immersive retreat.
We didn’t find direct comparisons of the effectiveness for improving wellbeing of neither the different formats (app, book, group…)^[101] nor the different types of meditation, but the program with the largest evidence in its favour for SWB seems to be MBSR.^[102] In general, longer and more intensive practices might come with increased benefits, but the evidence is very mixed.^[103]

Many media have been directly experimentally evaluated:

• The app Headspace^[104]
• The MBSR/MBCT online course Be Mindful^[105]
• The MBCT book Mindfulness: A practical guide to finding peace in a frantic world by Williams and Penman,^[106] and the MBSR book Wherever You Go There You Are by Kabat-Zinn^[107] 

In addition, people from the EA and LessWrong communities, who often discuss meditation and mindfulness, have shared a lot of recommendations, such as on:

• Apps:^[108] Waking Up app, Calm, Insight Timer, Medito, Balance
• Books and audiobooks:^[109] The Science of Mindfulness: A Research-Based Path to Well-Being, Why Buddhism Is True: The Science and Philosophy of Meditation and Enlightenment, The Mind Illuminated, Waking Up
• Retreats: Vipassana retreat^[110] and many others
• Online programs: Finder’s Course, and programs^[111] specifically for EAs (let’s finally add this MBSR program we mentioned in our Stress article, as well as these free exercises)
   

A big caveat is that even if our process ended up making mindfulness land in the first position of our recommendations, one should be aware there are important issues^[112] with the evidence quality, which should at least lead us to consider that the true effect size is probably quite smaller than what is indicated here. We therefore suggest you pay special attention to whether you really personally get benefits from this practice, and whether the commitment it may take you (e.g. 15 minutes of daily meditation) is worth it.
 

Best Possible Self

Size of effect: 0.35

Intervention: Imagining and writing about your life and the best version of yourself in the future after everything has gone as well as it possibly could.
 

The Best Possible Self interventions aim to increase happiness by cultivating optimism about the future, a trait that seems to have beneficial effects on wellbeing.^[113] The most common form consists in following these instructions or a close variant: “Think about your life in the future. Imagine that everything has gone as well as it possibly could. You have worked hard and succeeded at accomplishing all of your life goals. Think of this as the realisation of all your life dreams. Now write about what you imagined”.^[114]

A standard additional instruction is to then explicitly dedicate some time to the visualisation of your best possible future. Two other small variations in the form of the practice are, first, that sometimes you’re asked to repeat the activity daily for one or two weeks, or alternatively sometimes weekly for e.g. a month, and, second, that sometimes different themes or life domains are provided to guide your writing.^[115]

None of these variations - presence or absence of visualisation,^[116] daily or weekly dosage,^[117] and life domains^[118] - has been shown to have an impact on effectiveness. It also does not seem beneficial to spend too much time on the activity, e.g. more than two hours in total.^[119] Following the intervention online is plausibly as effective as in a physical session, even if the evidence is quite undetermined.^[120] Finally, as positive effects seem to fade out with time,^[121] it may be a good idea to repeat the activity regularly, for instance every quarter, to cultivate a sense of optimism and sustain your motivation to work towards the desired future you imagined.

The procedure for this activity is pretty straightforward, but you can use these resources for its practical implementation:

• The Best Possible Self practice from Greater Good in Action, that they also have for relationships (15 min/day for 2 weeks)
• This worksheet from Therapist Aid (20 min then 5 min/day for 1 week)
• This worksheet from The Wellness Society (10 min/week for 4 weeks)
• The section My future self from Clearer Thinking’s Mood Boosters program (3 min one time)

The section Happiness Activity No. 2: Cultivating Optimism from Chapter 4 of Sonja Lyubomirsky’s book The How of Happiness also gives a few other suggestions on how to increase optimism.^[122]
 

Compassion interventions (including self-compassion and loving-kindness meditation)

Size of effect: 0.35

Intervention: Following practices aimed at increasing compassionate attitudes towards others and yourself, like compassion-focused therapy or loving-kindness meditation.
 

The psychological construct of compassion refers to both the short-term state and the longer-term trait of “being touched by the suffering of others, opening one's awareness to others’ pain and not avoiding or disconnecting from it, so that feelings of kindness towards others and the desire to alleviate their suffering emerge”.^[123] A particular form of compassion is self-compassion, which involves the same aspects but directed towards one's own suffering, and can be described as a positive and caring attitude of a person towards him- or herself in the face of failures and individual shortcomings. Self-compassion interventions aim to foster reactions to events that are characterised by self-kindness, a sense of common humanity and mindfulness.^[124]

This intervention includes programs designed to train compassion (for instance by interacting with another person in a supportive or considerate way^[125]) in order to improve wellbeing and ethical sensibility, as well as other programs specifically developed to help work on increasing compassion for the self. It also includes^[126] loving-kindness meditation^[127] (LKM), a popular form of the kindness based-meditations developed to elicit kindness in a conscious way, which fosters the inner cultivation of a loving acceptance feeling towards all sentient beings and a harmonisation with the needs of others. Exercises involve for example the repetition of short phrases (e.g., I wish you peace and joy) or the visualisation of light flowing from oneself to others.^[128]

What makes a compassion intervention more effective is not very clear.^[129] Self-compassion interventions might be more beneficial to women.^[130] Loving-kindness meditation interventions can be strengthened when they include teachings on the philosophy of the practice,^[131] but, as with mindfulness meditation, whether longer and more intensive practices lead to higher results is uncertain.^[132]

The two most studied^[133] programs focused on compassion are Mindful Self Compassion (MSC) and Compassion Focused Therapy (CFT).

MSC is a 8-week program developed to help participants enhance their self-compassion, as well as secondarily learn basic mindfulness skills, through formal - like sitting meditation - and informal - like daily self-compassion habits - experiential exercises, group discussions, and homework assignments designed to help them learn how to be kinder to themselves.^[134] The Center for Mindful Self-Compassion, founded by Kristin Neff, lists various formats of MSC courses, but they are quite expensive - several hundred dollars for the 8-week program. So alternatively you can check Neff’s guided practices and exercises on her website and The Mindful Self-Compassion Workbook (or her classic Self-Compassion book). Week 2 of the EA Mental Health Programme is also dedicated to self-compassion.

Rooted in a theory of emotion regulation influenced by evolutionary psychology, that stresses the importance of affiliative and kind relationships in regulating mental states,^[135] CFT aims to help individuals who struggle to access their “soothing system” respond to self-criticism with self-kindness and compassion in order to improve their wellbeing. Activities specifically designed to develop compassionate attributes and skills are used, which is called compassionate mind training. Sessions can include practices such as the use of imagery, compassionate thinking to the self and others, responding to self-criticism through self-compassion, practising compassionate behaviour, and letter or diary writing.^[136] You can find (expensive) CFT trainings on the website of the Compassionate Mind Foundation, the charity founded by Paul Gilbert, the researcher behind CFT, as well as resources such as a selection of books, including The Compassionate Mind Workbook^[137] and the popular The Compassionate Mind by Gilbert. CFT is also described here by David Althaus and Ewelina Tur.

The Compassion Cultivation Training is yet another program, although less evaluated, designed to cultivate the qualities of compassion, empathy, and kindness for oneself, loved ones, difficult people, and all beings, with a strong focus on meditation practices.^[138] Finally, Greater Good in Action offers a guided Loving-Kindness Meditation.^[139]
 

Physical activity

Size of effect: 0.31

Intervention: Doing some exercise, without focusing on the specific type or intensity.
 

It should not be a surprise to you that increasing your level of physical activity can result in more positive emotions and higher wellbeing, and it turns out it is one of the best things you can do for this purpose.

Physical activity (PA) was defined as any movement resulting in energy expenditure in the reviewed studies, which included all kinds of sports (power walking, jogging, dancing, football…) and exercise types, be it resistance training or aerobic exercise.

Any means of being physically active is relevant, as evidence indicates an absence of notable differences in wellbeing benefits when various activity characteristics are compared. We can expect on average the same effectiveness from individual vs. team sports, from light vs. moderate vs. intense exercise, and from aerobic (like jogging) vs. anaerobic (like resistance training) exercise.^[140] Your prior fitness level should not have an influence either.^[141]

The optimal volume of exercise for improving wellbeing remains mostly unknown,^[142] although weak evidence suggests that the more activity you do the better,^[143] up to a certain level where increasing activity has diminishing returns, plausibly starting from around 150 minutes per week.^[144] The frequency of exercise can also have a positive influence, but it may be only because it is associated with a higher total volume.^[145] In any case, don’t let too high ideal practice targets deter you from being even a little active, as even small amounts of PA come with their benefits.^[146]

In line with recognised reliable institutional guidelines, what we think makes most sense in terms of which activity to pick, is to choose activities you find enjoyable and/or that you can fit in your routine. This also applies to the choice of the way to practise (e.g. in a club, with an app… ; in the morning, in the evening…) among the countless alternatives that exist.

We haven’t looked at the evidence on this topic in detail, but effective interventions to increase your chances of developing physical activity habits include, among others, goal setting, using prompt and cues, action planning and relying on social support.^[147] 
 

Multi-component Positive Psychology Interventions (MPPIs)

Size of effect: 0.30

Intervention: Following a combined package of a variety of positive psychology exercises like using strengths, practising gratitude, active constructive response, counting blessings or savouring, often conducted within an integral program.
 

A lot of the reviewed interventions in this guide stem from the field of positive psychology,^[148] with the term positive psychological interventions (PPIs) referring to “treatment methods or intentional activities that aim to cultivate positive feelings, behaviours, or cognitions”.^[149] Multi-component positive psychology interventions are based on a variety of individual activities targeting several wellbeing “components” such as gratitude, hope, or character strengths.^[150] They are often delivered as a broad program lasting several weeks.

The reviewed papers couldn't indicate what makes a MPPI more effective,^[151] except the very weak evidence that completing exercises on a weekly basis might be better than daily.^[152]

A lot of different programs are described in studies^[153] but they’re nearly always unavailable for public use. We fortunately found some resources in various formats^[154] that appeared close in content to the most evidence-based programs:

• Books:
  • The Mayo Clinic Handbook for Happiness (also as an Audible audiobook), issued by the reliable institution, guides you through a 10-week program that covers an extensive range of evidence-based happiness practices.
  • The How of Happiness^[155] by Sonja Lyubomirsky, although a bit old, presents a host of classical positive psychology exercises that can be considered a program if you test many of them to see which work best for you.^[156]
• Online courses or programs:
  • The Pathway to Happiness program from Greater Good in Action provides some structure to follow their proposed practices on a weekly basis for a month. They also have an edX MOOC.
  • The Coursera course The science of wellbeing mixes discussions of research results with instructions for personal application.
  • The courses in the Coursera specialisation Foundations of positive psychology give a broad overview of the field and contain many exercise instructions, but you can skip the more theoretical parts and focus on the practices.
  • The course The Science of Happiness: Theory & Practice by the nonprofit The Pursuit of Happiness Project teaches basic findings of happiness research relevant for individuals, then practical ways to implement them in your life.

Discussion of Promising interventions with a strong evidence base but a smaller effect size

Using character strengths

Size of effect: 0.29

Intervention: Identifying positive qualities through a self-report survey and using them in your daily life for a period of time.
 

The term character strengths refer to a type of psychological strengths, i.e. positive characteristics, that are considered to be relatively durable individual attributes and somewhat universal across time and cultures.^[157] In theory, identifying and increasing the use of one’s most prominent character strengths, what researchers have termed signature strengths, can have beneficial effects, as using them may, in addition to being intrinsically motivating and satisfying, allow individuals to get closer to optimal functioning.

Interventions intended to foster character strengths identification and use have thus been developed within the field of positive psychology. They typically involve people being taught about their signature strengths after having completed a self-report questionnaire, and then asked to use them in their daily lives for e.g. a week.

Longer interventions don’t seem to be more effective,^[158] so there is probably no need to continue focusing on this intervention for a long time if you don’t feel it’s beneficial.

As mentioned, most resources focused on the application of character strengths consist simply in getting you to assess and put in practice your strengths:

• Following the instructions of the Use Your Strengths practice from Greater Good in Action should be one of the simplest ways to do the intervention. You can use this list of activities (in the Appendix of this linked document)^[159] to find inspiration on ways of using each strength.
• The VIA Institute on Character, a non-profit co-founded by Martin Seligman, is the main organisation focused on character strengths, and is famous for its VIA Character Strengths Survey. They also propose reports to guide you in applying your strengths, as well as courses and resources, like activities and exercises and self-help books.
• From the Coursera specialisation Foundations of positive psychology, the last course Positive Psychology Specialization Project: Design Your Life for Well-being tackles the theory and practice of character strengths, and Week 4 of the course Positive Psychology: Resilience Skills also centres on identifying and using them.

Acts of kindness

Size of effect: 0.26

Intervention: Performing small actions embodying a kind behaviour to help other people, or spending money on others.
 

Acting in a way that is kind to other people should be a quite reliable way to boost your happiness. Acts of kindness work as a happiness intervention possibly because they can enrich social integration, work as distraction from problems and promote activity.^[160] 

The most frequent instructions for this intervention are to directly ask people to perform “acts of kindness”, typically five per day for a week. Examples of such acts include holding the door for someone, greeting strangers, helping a friend with a chore, or providing a meal to a person in need. Two close instructions are to spend a sum of money on someone else (which is called prosocial spending), or to engage in “social recycling”, i.e. disposing of used goods by allowing other consumers to acquire them at no cost.^[161]

When it comes to spending money on others, three criteria must be met for it to be beneficial: first, the act must result in a feeling of being close to another individual, second, the benefits to the receiving party should be apparent to other people, and third, the donating individual must feel autonomous in one’s actions, not coerced or forced.^[162] A study examining survey data from the Gallup World Poll found that “donating to charity has a similar relationship to SWB as a doubling of household income.”^[163]

At the meta-analytical level, acts of kindness have not been found to be a more effective intervention for specific groups of people, and are as effective as specifically prosocial spending.^[164] Neither do we know if it’s more beneficial to perform such acts on people we know or on strangers.^[165] Weaker evidence indicates that it’s more beneficial to perform five acts of kindness in a single day than single acts of kindness once a day across a week, and that an element of novelty must be involved, i.e. that engaging in a new behaviour is more effective than relying on already habitual actions. Another weak finding is that recalling kind acts performed in the past is plausibly as beneficial as actually doing new acts of kindness.^[166]

Of course, while it’s perfectly legitimate to perform acts of kindness mostly for personal satisfaction, there is no reason to expect them to be particularly effective.

The activity is described in the practice Random Acts of Kindness by Greater Good in Action - and you can also check their other kindness practices. Many ideas of actions and resources can be found on the site of the Random Acts of Kindness Foundation, as well as on the sites of the Mental Health Foundation and the nonprofit Kindness. The idea is essentially to increase the number of times you act in a kind way and integrate it in your more habitual behaviour, while still maintaining some variety.
 

Gratitude

Size of effect: 0.22

Intervention: Engaging in brief activities designed to cultivate a sense of gratefulness, such as daily writing of things for which you are grateful, or expressing gratitude through a letter to someone who has been helpful to you.
 

Gratitude practices are one of the most tested ways of improving subjective wellbeing. Gratitude has been defined as “a generalised tendency to recognize and respond with grateful emotion to the roles of other people’s benevolence in the positive experiences and outcomes that one obtains”,^[167] or more simply as a “positive response to receiving a benefit”.^[168] It can be thought of not only as a trait, namely a stable personal predisposition, but also as a mood, meaning it fluctuates throughout or across days, and as an emotion, i.e. a short-term reaction to a particular event.^[169]

As they’re designed to increase appreciation of positive qualities, situations, and people in one’s life, gratitude interventions might in part work by helping people defy the hedonic treadmill.^[170] The evidence base in favour of them is vast,^[171] but we found a relatively modest effect size, which was a bit of a surprise given the popularity of the practices. So enthusiasm should likely be somewhat tempered.^[172]

There doesn’t seem to be a variation in effectiveness between the different types of gratitude interventions (those using journals or lists, compared to those involving an expression of gratitude),^[173] nor between men and women.^[174] Volume of practice doesn’t appear to make a strong difference either,^[175] and we still don’t know the optimal frequency of practice, i.e. daily vs. weekly practice.^[176]

Many exercises have been developed to induce or enhance gratitude.^[177] The most classic intervention is gratitude journaling. It typically takes the form of a “count your blessings” exercise where you write five things for which you are grateful, either weekly or daily. Another often-studied practice is the gratitude letter, which is about writing a letter of gratitude to someone who you have never properly thanked, and then sometimes delivering the letter in person in what is called a “gratitude visit”. Other practices are the mental subtraction exercise and gratitude meditation. 

The gratitude practices from Greater Good in Action include all these exercises and a few more, and EAs and rationalists have discussed gratitude exercises as well. The book Gratitude Works! by Robert Emmons seems to cover many techniques and tips, and contains a three-weeks program to develop gratitude.^[178] Lastly, several gratitude apps also exist.
 

Singular Positive Psychology Interventions

Size of effect: 0.20

Intervention: Practising an individual exercise from positive psychology, such as doing a best possible self exercise, practising gratitude, doing acts of kindness, using your strengths in a new way or savouring the moment.
 

The effect size above doesn’t actually refer to a single identifiable intervention, but represents the combined effect size of several singular positive psychology interventions (SPPIs), i.e. “singular” meaning that they don’t incorporate a mix of different positive psychological exercises in one intervention. So it is somewhat useful to get a sense of the effectiveness of positive psychology interventions in general, and an idea of the effect you could expect on average from following one of the interventions included in this aggregation.

Most interventions included in the three meta-analyses we reviewed here are already covered in this article: best possible self, character strengths, compassion, forgiveness, gratitude, kindness, mindfulness, reminiscence. But one or more of these meta-analyses also included the interventions of savouring, gift of time, humour, meaning making, and cultivating sacred moments.

While there might be issues with positive psychology research, as mentioned in the sections Limitations of our research and Multi-component Positive Psychology Interventions (MPPIs), there is nonetheless a large evidence base in favour of PPIs,^[179] even if the effects are often quite modest. Furthermore, there is evidence that interventions relying on technology are likely less useful than the ones that don’t, that longer interventions have a stronger effect, and that younger people get more benefits from PPIs.^[180]

Focusing on multi-component positive psychology interventions rather than on singular ones does appear to be a better choice for improving your subjective wellbeing, given their relative effect size. More concretely, this is an additional reason to give a try to various activities and exercises before committing to an individual one.

We won’t go into their details as they’re much less researched and used^[181] - so resources to apply them are scarce - but you’ll find in the links some resources you can use to learn more about and practice the interventions of savouring,^[182] gift of time,^[183] humour,^[184] meaning making,^[185] and cultivating sacred moments.^[186]
 

ACT

Size of effect: 0.20

Intervention: Following an intervention based on ACT principles. ACT interventions seek to increase psychological flexibility (defined as the ability to face challenging experiences in an open, conscious manner and change one’s behaviours to participate in valued activities) through acceptance of difficult and unwelcome thoughts or emotions and a commitment to one’s personal values. For instance they use techniques like mindfulness or exposure exercises to develop cognitive defusion skills.
 

Acceptance and Commitment Therapy (ACT) is an empirically supported form of psychotherapy, seeking to both alleviate distress and foster more adaptive behaviours by enhancing people’s psychological flexibility. The aim is to allow people to experience life while taking appropriate distance with their thoughts and feelings, without unsuccessfully trying to control them through suppression and avoidance, but rather accepting them.^[187] We recommend this EA Forum article to learn more about ACT’s key ideas and principles.

In addition to being helpful for treating psychological disorders, ACT interventions can be used to improve wellbeing, in part thanks to ACT’s practices like mindfulness and values-based goal setting and action, as well as due to its general focus on increasing psychological flexibility^[188]. But the magnitude of the effect is quite small and the evidence is not entirely settled, as three out of the six meta-analyses we reviewed didn’t find an effect - yet note that these three evaluated quality of life and not directly SWB.

The effectiveness of ACT interventions doesn’t appear to be affected by the length and number of sessions, or the age and gender of participants.^[189]

One way to learn ACT techniques would be to work with a therapist trained in them.^[190] Alternatively, you can use the empirically supported^[191] classic book Get Out Of Your Mind And Into Your Life by Steven Hayes. Many additional resources, like self-help books, exercises or videos, can be found on the Association for Contextual Behavioral Science website and in the aforementioned forum post.
 

CBT

Size of effect: 0.19

Intervention: Following an intervention or program (including in a book or online program format), typically over multiple sessions, using a cognitive and/or behavioural approach. They generally focus on identifying and disputing maladaptive thinking patterns, and developing coping, emotional regulation, problem solving and goal setting skills.
 

Cognitive behavioural therapy (CBT) is a popular and strongly empirically supported^[192] therapeutic approach for treating common mental health problems such as depression and anxiety. But there is also direct evidence, although less extensive, that practising CBT can very slightly increase subjective wellbeing for the general population. A rationale is simply that CBT encourages more healthy patterns of thinking and behaviour, which promotes positive mental health.^[193] Here are some good overviews of CBT.

While the evidence base on CBT for depression and anxiety is large and detailed, much less seems to be known for subjective wellbeing: we didn’t find meta-analytical evidence on what makes a CBT intervention more useful in increasing happiness (e.g. in format, length), nor for for whom it works best. The results from one RCT indicate though that the effect of CBT for wellbeing can be expected to be consistent across age, gender, psychiatric history, previous use of CBT, level of anxiety and level of depression.^[194] As for the mode of administration, a meta-analysis compared the efficacy, for various common psychological disorders, of in-person therapy versus self-help CBT and found no difference in effectiveness.^[195]

If you want to follow CBT with a trained professional, you can check the list of Community-recommended providers and coaches in EA, as many of them offer CBT. Alternatively, there exists a wealth of resources (like books, courses or apps) to learn and practise CBT techniques, and you shouldn’t have difficulty finding some that suit you. A good starting point can be the NHS page on Self-help CBT techniques. From the meta-analyses we reviewed, the only accessible program with empirical evidence we found is the online self-help course moodgym,^[196] which costs around $30. (There is also evidence that the book Control your depression increases life satisfaction.)^[197]

The EA and rationalist communities have also shared many resources. At ESH, we’ve made CBT recommendations for stress and sleep. The EA Mental Health Programme has a section on CBT techniques, as does this article from 80,000 Hours’ 2017 career guide. The book Feeling Good by David Burns, in favour of which there is evidence for depression, is often recommended as well as discussed. There is also enthusiasm for Burns’ recent book Feeling Great, based on the TEAM-CBT framework, which is intended to make CBT therapy more effective. Another reference CBT manual is Mind Over Mood, recommended for instance by Ewelina Tur. In terms of apps, Scott Alexander mentions IntelliCare.
 

Discussion of Most promising interventions with a weaker evidence base

Leisure

Size of effect: 1.02

Intervention: Improving your leisure engagement, i.e. the participation in satisfying leisure activities such as social activities, sports, games, or cultural experiences.
 

Improving your engagement in leisure activities is both a quite intuitive and intrinsically pleasant way to improve your subjective wellbeing. Leisure engagement simply refers to the amount of time, diversity, or frequency of your participation in leisure activities, such as social activities, playing sports, games, cultural experiences, creative arts, or any activity you view as leisure.^[198] 

The increase in wellbeing from leisure activities is thought to come from the satisfaction of a wide range of psychological needs, most notably from the experience of intrinsic motivation and perceived freedom fostered by such activities. Theoretical models and empirical evidence indicate that these two features, intrinsic motivation and perceived freedom, can be seen as defining characteristics of leisure activities, distinguishing leisure from other activities like work. And the experience of intrinsic motivation and perceived freedom has been shown to enhance subjective wellbeing. Additionally, engaging in leisure activities might influence SWB through the fulfilment of one or several other needs, like detachment from work-related thoughts, recovery from work stress, autonomy, mastery, meaning, and affiliation.^[199]

Not surprisingly, interventions with a longer duration and a higher number of leisure hours were found to be more effective.^[200] And cross-sectional data indicate that leisure engagement is more strongly associated with SWB for retired than working samples.^[201]

The interventions included in the meta-analysis we reviewed were mostly programs specifically designed to improve the quality of participants’ leisure activities, called leisure education programs. They typically consist of weekly sessions spanning two or three months led by a professional facilitator such as a recreational therapist. They first explore with the participants the benefits of leisure activities, then seek to familiarise them with a wide range of potentially satisfying leisure experiences, with a consideration for each participant’s preferences and constraints. Lastly, time is often dedicated to the practice of the individually chosen activity.^[202]

One major limitation of leisure interventions is that the programs are designed for and have been tested on either retired or disabled populations: out of the six RCTs included in the reviewed meta-analysis, half of them are on older people and the other half on physically or mentally disabled participants. The sample sizes are also notably small, and half of the RCTs are not peer-reviewed. So the effect size of 1.02 should definitely not be taken at face value, even more so given that it’s in big part coming from one of the six studies that is likely very unrepresentative of an actual implementation.^[203]

Having said that, while it’s clear that this is at least a bit different from following a leisure program strictly speaking, taking actions to improve the quality of your leisure experience still holds promise for enhancing your SWB. You can do it by focusing on the three obvious dimensions of leisure engagement: (1) the diversity of your leisure activities, i.e. how many different ones you engage in, (2) their frequency, i.e. how often you participate in different leisure activities, and (3) the amount oftime you spend on leisure, i.e. how many hours you spend on leisure experiences.

Spending your leisure time on mostly one single activity can be conducive to SWB, as the acquisition and expression of special skills and knowledge it allows can generate feelings of accomplishment, meaning and growth. However, engaging in a broader range of activities is plausibly more effective for satisfying a wide range of needs, because no single type of leisure activity is likely to satisfy them all at once. Furthermore, maintaining a “broad leisure repertoire” - a reasonable variety of activities you enjoy and practice - may be a more prudent strategy, since it can help protect your leisure satisfaction in the face of risks of increasing leisure constraints associated with ageing, injury, loss of leisure partners or other life changes.^[204]

All in all, improving your leisure is mostly just about finding activities you enjoy and you can fit into your lifestyle and routines. You can find various ideas of activities to try out in these two lists,^[205] and cost-effective suggestions in this EA Forum post.
 

Sleep

Size of effect: 0.54

Intervention: Following an intervention aimed at improving sleep quality (i.e. continuity and daytime impact) such as CBTi.
 

While the association between sleep and mental health is already established and well-known^[206], we found more direct and robust experimental evidence that improving your sleep is likely to result in better mental health.

To go beyond mere association and to be able to conclude that changes in sleep quality^[207] do result in changes in mental health, the main meta-analysis we reviewed (Scott et al., 2021) aimed to isolate the direct effects on mental health of interventions that successfully improved sleep. The authors did it by selecting, from all the RCTs of interventions designed to improve sleep, exclusively the ones that did produce a statistically significant effect on sleep, and that then measured mental health at a later follow-up point.^[208] Their results indicate that improvements in sleep are indeed behind improvements in mental health. The interventions that successfully improved sleep quality had a significant medium-sized effect on mental health outcomes.^[209] More than this, the more effective an intervention was at improving sleep quality, the greater its effects were for mental health as well.^[210]

A large majority of the effective sleep interventions were based on Cognitive Behavioral Therapy for Insomnia, or CBT-I,^[211] while a few others used pharmacological treatments, sleep hygiene alone, sleep restriction alone, Tai Chi, or acupuncture (nonetheless considered a pseudoscience).^[212] Also, the interventions that were delivered face-to-face were more effective than the self-administered ones.^[213]

Note that a major limitation is that all interventions measured a mental health outcome (mostly depression, anxiety and stress) and not directly SWB, which is why we put sleep in the Weaker evidence base category.

At ESH, we previously wrote a report on effective ways to improve sleep, so unsurprisingly we recommend that you check it out for a review of some of the most worthwhile evidence-based practices, and in particular the discussion of CBT-I. You may also find the basic evidence-based advice from the NHS useful. Sleepio is an additional CBT-I self-help online program not mentioned in the Sleep report and in favour of which we found evidence for improving mental health.^[214]
 

Contact with natural environment

Size of effect: 0.50

Intervention: Spending some time in a natural environment (whether "wild", or "managed" nature such as parks), like taking a walk or looking at the landscape, or even viewing nature photographs.
 

Spending time and immersing yourself into nature has the potential to bring you positive emotions, even if the duration of the exposure is relatively brief. A theoretical reason for this increase is that, from an evolutionary psychology perspective, “the experience of positive emotions in many natural environments was likely adaptive throughout the majority of our evolutionary history”. A positive emotional response to natural environments rich in useful resources for survival, like food, water, shelter or raw materials, would encourage “approach-oriented” behaviours, i.e. it would increase the motivation to take action to acquire these resources.^[215]

Excluding non-experimental studies, the RCTs included in this intervention category examined “the effects of exposure to nature through direct physical or sensory contact or through laboratory simulations of nature”. Concretely, participants were instructed to either take a 15 to 60 minutes walk in the nearby woods or park, or to watch natural scenery (while being physically present in the natural environment or virtually through photographs).^[216]

Two findings from this research are especially interesting.

First, exposure to both real and simulated nature have beneficial effects on wellbeing. Consequently, and while the benefits of real nature remain greater, exposing yourself to virtual nature is a good option if you do not have access to actual natural environments.^[217]

Second, the effects on wellbeing of wild nature versus managed natural environments, like urban green spaces and arboretums, are similar.^[218] So you can probably consider managed nature spaces, such as big city parks, as fully adequate.

More generally however, it’s hard to be really confident in this intervention category, for a few reasons. From the three meta-analyses reviewed, only one of them used experimental studies - they represent about half of the total number of studies for the intervention. The experimental studies also involved a contact with nature in the order of magnitude of an hour maximum, while the studies measuring associations could include much greater durations.^[219] Additionally, in the experimental studies, measures of wellbeing were often taken right after a brief exposure to nature, so the results are mostly indicative of a short boost, but it’s quite unclear how long it lasts.^[220]

Exposure to nature is equally effective for men and women, but it plausibly becomes more effective as one gets older.^[221]

To increase contact with natural environment, you can simply incorporate even brief ventures in nature^[222] into your daily life. Or occasionally immerse yourself more intensively with hikes or camping. It’s also straightforward to practice in a natural setting (e.g. your local park) some interventions of this guide, such as physical activity, yoga, meditation or leisure. If it’s hard to be in real nature for any reason, like the weather or where you live, you can perhaps try to be creative to find ways to simulate nature.^[223]

Greater Good in Action also offers a practice to help you notice nature more.
 

Yoga

Size of effect: 0.46

Intervention: Practising yoga a few times per week, whatever the type.
 

The practice of yoga, originally rooted in Indian philosophy, is a “mind-body physical activity that includes a combination of stretching and holding movements and postures in addition to meditation and focused breathing”.^[224] Various schools of yoga exist, but they all seek to promote and restore health in mind and body using the base triad of meditation (dhyana), postures (asanas) and breathing (pranayama). The postures involve standing, bending, twisting and balancing the body to improve flexibility and strength. The controlled breathing is meant to help focus the mind and achieve relaxation while meditation aims to calm the mind.^[225] 

According to Hendriks et al (2017), “positive psychology and yoga share much common ground when it comes to their specific goals; both focus on achieving wellbeing, increasing meaning in life, and personal growth”.

While yoga can seem particularly beneficial as a form of combination of mindfulness^[226] and physical activity, direct evidence for its effectiveness in improving well-being is more modest.^[227] 

We didn’t find evidence of the superiority of a particular length of practice, nor that it’s more effective for specific groups.^[228] Additionally, the type of yoga doesn’t appear to matter.^[229] A systematic review of 306 RCTs on the effects of yoga on various physiological and psychological outcomes found no differences in efficacy between the yoga styles. The authors thus recommend that the choice of yoga style be based on personal preferences and availability.^[230] The most commonly studied styles though are Hatha yoga and Iyengar yoga.^[231]

Our search for directly evidence-based resources wasn’t conclusive. But here is a flowchart made by a physician for choosing a yoga style (Hatha and Iyengar are described in the Active but Accessible Styles section of the paper, and many popular styles are described here). The NHS has a 50 minutes vinyasa flow yoga instruction video, and Mayo Clinic has yoga poses instructions and videos. Otherwise you can just find a way to guide your practice that suits you: written instructions,^[232] Youtube videos, an app, or classes with a qualified instructor, which is recommended for beginners.
 

Expressive writing

Size of effect: 0.45

Intervention: Completing a brief written emotional expression task over a period of time, like writing an essay that expresses your feeling about a negative, stressful or traumatic experience in your life, and that focuses on how the event related to your life, what coping methods you used and whether these were successful.
 

Writing about emotion-laden events, especially related to traumatic or particularly stressful experiences, can promote the assimilation and understanding of those events, thus reducing negative feelings associated with them.^[233] There are many possible causes or theories to explain the effectiveness of expressive writing. One hypothesis is that by putting previously inhibited experiences into words, people stop holding back thoughts, emotions and behaviours on the events, which is more generally associated with better health. Another potential explanatory mechanism is that translating emotions into language format allows for an event to be better processed: describing the experience with words makes it easier to assign meaning, coherence and structure to it, which favours the assimilation, resolution and/or forgetting of the event.^[234]
 

While the overarching effect size we present is quite high, a caveat is that among the two meta-analyses we reviewed, the most recent one from 2021 found a (non-significant) effect size much lower than the one from 1998, which is arguably made much less relevant by the recent one.^[235] And the overall evidence quality for this intervention remains shaky.^[236] Still, even if expressive writing can be particularly helpful for you if you went through a traumatic experience, the topic of the writing is by no means restricted to such events, as the intervention can be applied to any emotionally charged event.^[237]

Expressive writing might be more effective for improving your wellbeing if you write about current traumas (as opposed to past ones - but it’s probably not judicious if it feels too overwhelming), as well as possibly if you’re male and if your expressive writing sessions are spaced over longer periods than only a day.^[238]

You can find the basic writing instructions on the Expressive Writing practice from Greater Good in Action. They ask to write for 20 minutes per day for four consecutive days, but note that instructions vary a lot depending on the source, from 10 to 30 minutes writing sessions, for three, four, or five days, or sometimes within the same day, or alternatively once per week for up to four weeks.^[239] You can also use one of the two books written by James Pennebaker, the most famous researcher on expressive writing, Expressive Writing: Words That Heal and Opening Up by Writing It Down^[240]. The first book seems more oriented towards practical application of the techniques, while the second seems to focus more on the findings from research on expressive writing. The website for Expressive Writing: Words That Heal also has resources such as instructions, articles and other books from the author.^[241]
 

Discussion of Promising interventions with a weaker evidence base and a smaller effect size

Forgiveness interventions

Size of effect: 0.38

Intervention: Following a multi-session forgiveness program, in which the potential benefits of forgiveness are emphasised, the development of empathy for the offender is encouraged, and in which emotional regulation, cognitive and behavioural strategies are used to decrease the negative impact of the hurtful interpersonal experience on your life.
 

The common experience of interpersonal hurt, i.e. hurt resulting from a conflict between people (whether occurring in a violent form such as bullying, or more typically in the form of offence within an otherwise healthy relationship) can lead those experiencing such hurt to feel emotions like chronic anger and hostility. But, in addition to potentially leading to a cycle of violence and frustration from seeking revenge, these emotions can result in physical and mental health problems for the person harbouring them.^[242]

Some psychologists have put forward the idea of forgiveness as a more beneficial response in the face of interpersonal hurt, emphasising its adaptiveness and potential to bring several benefits,^[243] which includes a strongly supported association with higher levels of subjective wellbeing.^[244] Forgiveness has been defined as “the decision to let go of negative resentment-based emotions, cognitions, and behaviours and developing positive regard for an offender, be it compassion, sympathy, or pity”.^[245]

Forgiveness interventions most often take the form of programs using a range of cognitive, affective, and behavioural strategies to encourage the development of empathy for the offender, after having defined forgiveness and emphasised its potential benefits.^[246] The two most widely used programs, both considered “process-based”, are based on a model promoted by Robert Enright, and on the REACH model developed by Everett Worthington. Enright’s model consists of twenty steps divided in four work phases described here, while the five steps of the REACH model are described here.

Two qualifications on forgiveness interventions are that a few critical points have been raised against them, and that they are of course primarily intended for people who have experienced interpersonal problems,^[247] even if they’re also entirely relevant for minor offences^[248] and possibly for improving close relationships.^[249]

Although the effectiveness of the self-guided format for forgiveness interventions remains uncertain,^[250] you have the choice to follow a number of different resources:

• Books:
  • Based on Enright’s model: his classic book is Forgiveness is a choice, and his more recently written books The Forgiving Life^[251] (on Amazon) and Eight keys to forgiveness^[252] (on Amazon, including as an audiobook)
  • Based on the REACH model: the three workbooks^[253] on forgiveness by Worthington and his Books for All Readers (but note that some of them are to varying extents imbued with christian ideas)
  • Forgive for good by Fred Luskin, although we haven’t reviewed the forgiveness approach on which this book is based
• Other formats:
  • Various resources (for instance at the bottom of this page) on the website of the International Forgiveness Institute founded by Enright
  • Various resources from the charity The Forgiveness Project
  • A worksheet from Enright’s Forgiveness Therapy
  • Forgiveness practices by Greater Good in Action
     

Reminiscence interventions

Size of effect: 0.24

Intervention: Reviewing past life experiences, like difficult events or positive memories, notably as part of life review therapy.
 

Reminiscence, defined as the process of thinking or telling someone about past experiences that are personally significant, can be used as a central mechanism of some happiness enhancing interventions. Three common forms are simple reminiscence, an unstructured autobiographical storytelling intended to enhance positive feelings, life-review, which focuses on the (re-)evaluation of life events and on the integration of positive and negative life events in a coherent life story, and life-review therapy, a structured form of reminiscence therapy mainly targeting mental health problems through various techniques.^[254] These forms of reminiscence interventions - which are the most studied ones by and large - are foremost directed at older adults,^[255] which should lead you to discount quite heavily these interventions if you’re not one yourself.

However, some researchers highlight theoretical arguments and empirical evidence indicating that reminiscence interventions can also be useful for young and middle-aged adults (though mostly for treating depressive symptoms).^[256] In particular, we found an intervention that people of all ages can follow, described in one RCT on young adults where a reminiscence activity improved their wellbeing.^[257] The activity consists in recalling autobiographical memories and answering questions to facilitate reflection on the memories. The memories should either be about a challenging experience where you successfully coped with adversity, or about a “self-defining” event that contributed to your sense of having a meaningful and continuous personal identity.
 

Here are slightly adapted instructions:
 

“You will have to focus on a memory from sometime in your life. The activity, on which you’re advised to spend at least five minutes, will involve recalling and revisiting this memory, and then answering a small number of simple questions about it.

1) Think back over your life to:

(a) either a time in your past when you successfully coped with a challenge in your life.

(b) or an event or experience in your past that was meaningful and helped shape how you became the person that you are.
 

2) Now take a few minutes to close your eyes, clear your mind and focus on the memory chosen. Recall the time in your life, as well as thoughts or emotions, that best captured that memory and how you felt at the time.
 

3) Answer these questions pertaining to your chosen memory:

-Please provide a brief one or two sentence description of the experience you recalled.

-Please describe the important people related to this event.

-Was there anything significant or meaningful about this memory?

- (For the successful coping memory only) What plans and actions did you take to solve the challenge?

-What was the outcome?

-How did you feel about yourself when thinking about this?

-Thinking about this memory, what did you learn about yourself?”
 

Pleasurable experiences

Size of effect: 0.17

Intervention: Inducing pleasure by writing about three things found pleasurable each day for e.g. one week. This may include things that made you feel happy, experience positive emotions, laugh or feel joy and satisfaction.
 

Writing about positive and pleasurable experiences, including with the aim of reliving the moment, is thought to foster greater understanding of emotions, priorities, and goals, as well as help with reevaluation of and insight into past events.^[258]

The practice instructions for the “pleasurable experiences” intervention differ slightly depending on the source, with for instance:

• For 20 minutes for three consecutive days: “Think of the most wonderful experiences in your life: happiest moments, ecstatic moments, moments of rapture, perhaps from being in love, being in nature, achieving a personal project, from listening to music, or from some great creative moment. Choose one such experience. Try to imagine yourself at that moment, including all the feelings and emotions associated with the experience. Now write in as much detail as possible.”^[259]
   
• “Please take 10 min on every evening for a week before going to bed. Remember three things you have experienced today that were related to fun, amusement, joy, or pleasure. Write these three things down and describe how you felt.”^[260]
   
• For twelve consecutive days, writing down three items which made you feel happy, after having focused and reflected on these questions on emotional states: “What do I remember right now that makes me feel happy ; What do I feel right now that makes me feel happy? ; What can I hear right now that makes me feel happy? ; What can I see right now that makes me feel happy? ; Who did I see today that made me feel happy?”^[261]
   

Even though they were considered two distinct interventions in the common meta-analysis evaluating them, the intervention “Pleasurable experiences” and the exercise “Three good things” just below appear really close. “Pleasurable experiences” interventions just focus more on inducing feelings of joy and satisfaction, especially by recreating the emotion associated with the event, while the “Three good things” activity tries more to encourage a grateful attitude.
 

A non-significant intervention: Three good things

Size of effect: 0.14

Intervention: Writing and thinking about three things that went well over a period (typically reflecting back on the same day) and reflecting on why those things occurred, repeating this task for a number of days, like a week.
 

This activity, while very simple and easy to do, doesn’t seem very promising according to the one meta-analysis we reviewed, where it was not possible to conclude that the three good things intervention had a significant effect. So we advise you to first check whether other interventions listed above, such as other gratitude exercises, are appealing to you before trying out this one.

Nonetheless, even if doing the exercise on its own may not be fruitful, it was often integrated with success in broader programs like Multi-component Positive Psychology Interventions. It is thus reasonable to test including it as one element in a larger set of happiness practices, especially given its brevity. Also, as personal fit remains an important factor in intervention effectiveness, it’s still possible that the practice will be fairly beneficial to you if it suits you particularly. This activity indeed stays one of the most popular positive psychology exercises.

Greater Good in Action provides basic instructions to practise the three good things exercise, as well as this pdf does.

Additional recommended resources

In addition to all of our previous recommendations, you might find these more general self-help resources on wellbeing useful:

• The content from UC Berkeley’s Greater Good Science Center^[262]: their numerous Practices, their magazine^[263] and podcasts.
• The online program of the charity Action for Happiness. The effectiveness of their main program is discussed here.
• Clearer Thinking Tools and Mini-Courses in the category Improve Your Mood.
• The book Creating Well-Being (on Amazon) - selection of “APA LifeTools Series”.^[264]

Acknowledgments

This article was written as part of a research internship at Effective Self-Help. I am very grateful to Ben Williamson for his continued support throughout the writing, as well as Anouk Hannot, Antonin Broi, JC Mourrat, Guillaume Corlouer, Lennart Stern, Manon Gouiran, Marc Terrettaz and Mata’i Souchon for their helpful comments and feedback. Views and mistakes are my own.

1. ^{^}

    Tov et al. (2022).

2. ^{^}

    Other relatively recent academic books include Wellbeing: A Complete Reference Guide or the Oxford Handbook of Happiness, and a reference textbook has recently been published (but we didn’t check its content). Yew-Kwang Ng also recently wrote a book on happiness. Finally, the entry Happiness and Life Satisfaction from Our World in Data is worth mentioning too, and you might find the yearly World Happiness Reports useful.

3. ^{^}

    Diener et al. (2018b), section Defining Subjective Well-Being.

^{^}

 Keyes et al. (2002).

^{^}

 Lyubomirsky and Della Porta (2010).

Among many other examples we found, Frijters et al. (2020) (in the Preamble) also use “happiness”, “life satisfaction” and “wellbeing” interchangeably (with some qualifications). In any case, note that according to Zheng and Chen (2018) “there is no consensus regarding the ‘gold standard’ of happiness measures”.

^{^}

 See also this post for a brief review of various theories, definitions, and operationalizations of the concept of wellbeing influential in psychology.

^{^}

 See Maccagnan et al. (2019) for a recent review of the benefits of high wellbeing, as well as Kansky and Diener (2017) and De Neve et al. (2013).

^{^}

 Diener et al. (2017) and (for only correlational evidence) Martín-María (2017).

^{^}

 Moore et al. (2018).

^{^}

 Diener and Tay (2017) use the expression “prosocial citizenship”.

^{^}

 Tenney et al. (2016).

We haven’t reviewed it in detail, but there is more evidence that happiness has positive causal effects on productivity.

^{^}

 Kansky and Diener (2017), section Well-being and resilience, and Parks and Layous (2016), section Happiness as a Protective Factor Against Mental Disorders. See also the introductory section of van Agteren et al. (2021) for an overview discussion on the interaction between mental wellbeing and mental illness.

^{^}

 Fredrickson et al. (2003). Note that some of Fredrickson’s research has been criticised.

^{^}

 Grant et al. (2013).

^{^}

 Keyes et al. (2010).

^{^}

 Diener (2000).

^{^}

 Oishi et al. (2007).

^{^}

 Diener et al. (2018a), section Outcomes of SWB.

^{^}

 Section Discussion, p.10-11.

^{^}

 Querstret et al. (2020), introductory section. Figure 2 in Huppert (2009) displays a visual representation of this idea, or Figure 1b in Aked and Thompson (2011). Note that some researchers rather view mental health/wellbeing and mental illness as two distinct continua (see Iasiello et al. (2020) for a review on this topic).

^{^}

 For short reviews of the factors associated with wellbeing, see Diener et al. (2018a), section Known influences of SWB or Diener et al. (2018b), section Predictors, Correlates, and Causes of SWB. The World Database of Happiness by Ruut Veenhoven also lists thousands of correlates of happiness.

^{^}

 Røysamb and Nes (2018).

^{^}

 Diener et al. (2018a).

^{^}

 Tay et al. (2018).

Income may be less relevant for citizens of rich countries, since, according to Clark et al. (2018), p.213: “Within most advanced countries income differences explain only 1% of the variation in happiness across people (other things equal), while all the factors we can identify explain 15% of the variation. Doubling a person’s income raises their happiness by under 0.2 points (on a scale of 0–10). Moreover people care largely about their income relative to other people.”

^{^}

 See these two posts for a recent discussion within EA.

^{^}

 Tay et al. (2018) gives a short overview of the research on income and SWB. If we limit ourselves to studies that include experimental interventions, this recent meta-analysis on the effects of income changes on wellbeing found a very small effect of 0.16 standardised mean difference for non “lifting out of poverty” - arguably more relevant for EA readers - income increases. We didn’t include it in our reviewed interventions because we stuck to easily implementable interventions an individual can follow.

^{^}

 Diener et al. (2018a), section Known influences of SWB.

^{^}

 The specific piece of data they use can be found in Clark et al. (2018), Table 16.1.

^{^}

 They explain the process to get to these numbers: “[The results are] based on the partial correlation coefficients in an equation in which life satisfaction is regressed upon log household income per head, years of education, whether or not unemployed, number of criminal convictions (times minus one), whether partnered, number of physical health conditions and whether diagnosed as suffering from a depression or anxiety disorder. Prior to running this regression, the outcome and covariates are standardized with means of zero and standard deviations of one. The square of each coefficient measures the fraction of the explained variance of life satisfaction that is independently captured by the variable in question.”

^{^}

 Their Figure 2 shows the relative contribution of these factors in a clear pie chart.

^{^}

 We averaged them when there were two or three available effects, and we left out white- vs blue-collar as it was not a “change” in the same sense as the others.

^{^}

 The other factors included in the survey were sex, marital status, age, education and religiosity, which also means that many additional possibly important factors were not taken into account.

^{^}

 It was not possible to rank these broad recommendations with the same methods we used for reviewed interventions, if only because we can’t have effect sizes for large and general advice.

^{^}

 We found this study, which uses the Delphi method, through this LessWrong article by Marius Hobbhahn. See in particular Table 3 for Expert rating of ways to greater happiness for a person can follow.

^{^}

 Clark et al. (2018), p.213.

^{^}

 You can also check the page on SWB from Examine for information on supplements affecting it, even if we have reservations regarding the strength of evidence on this matter.

^{^}

 Mujcic and Oswald (2016).

^{^}

 Among numerous good sources, you can find evidence-based advice in the high quality websites mentioned in the introduction of this section, such as the NHS Live Well advice.

^{^}

 Dale et al. (2014).

^{^}

 Let’s also mention this recent EA Forum post.

^{^}

 On that note, it’s interesting to see that extraversion is the personality trait with the highest correlation with wellbeing in the HEXACO model, and also one of the three strongest wellbeing correlates (with neuroticism and conscientiousness) in the Big Five (Anglim et al., 2020). The authors add: “efforts to improve well-being might target the most critical aspects of one's habitual or characteristic patterns of behavior and experience, as reflected in basic personality traits.”

^{^}

 In addition to improving your response to others’ good news, you could learn to give and to receive compliments to improve appreciation, as described respectively in the section Active Constructive Complimenting p.58 and in the section Active Constructive Accepting p.71 of a (non peer-reviewed) thesis by Singh (2017).

^{^}

 Peters et al. (2018). The researchers who proposed the term Active Constructive Responding to describe this way of responding indicate in this paper that they now favour the concept of “being responsive” to others’ capitalization attempts (i.e. sharing of good news). Regarding its evidence base, Schuller and Parks wrote in 2014: “Although, active-constructive responding is well liked, it has limited support for its efficacy as a standalone exercise. More research needs to assess whether it can increase its impact on happiness when delivered experimentally.”

^{^}

 Klug and Maier (2015).

They also write: “the fact that the predictive effect sizes were on average even slightly higher than the concurrent effect sizes points towards a causal interpretation and thus, emphasises the relative importance of successful goal pursuit for SWB.”

^{^}

 See in particular their Table 13.1 for an overview of the differential effects on subjective wellbeing of various goal characteristics.

^{^}

 In Klug and Maier (2015): “We differentiate between progress which represents the phase of goal pursuit including all steps that help to attain a goal and attainment which refers to a prescribed end state of the goal-striving process. The effect sizes for the progress-SWB relation were significantly stronger than for the attainment-SWB association.”

Hennecke and Brandstätter (2017), top of p.241.

Kaftan and Freund (2018), sections Goal Pursuit and Subjective Well-Being and Goal Focus but see the subsection Adaptiveness of Outcome Focus for some reservations.

^{^}

 In Klug and Maier (2015): “Studies in which participants were asked to provide a listing of their personal goals (idiographic approach) yielded slightly higher effect sizes than studies that used universal goal lists (nomothetic approach)” but “this significant difference between the effect sizes is minimal”.

^{^}

 Hennecke and Brandstätter (2017), section Good Goals, Bad Goals? The Role of Goal Content and Judge et al. (2005). This study also found an association between positive self-evaluations and the likelihood of pursuing self-concordant goals, the ability to select self-concordant goals being a skill in itself.

Sheldon et al. (2020) explain the higher benefits of pursuing self-concordant goals through an improvement in the “ability to interpret positive goal-outcomes in an optimistic way.”

^{^}

 Hennecke and Brandstätter (2017), section Approach vs. Avoidance: The Role of Goal Orientation.

^{^}

 Hennecke and Brandstätter (2017), sections Good Goals, Bad Goals? The Role of Goal Content and Goals Have to Satisfy Affective Needs: The Role of Implicit Motives.

On striving for financial success, they write: “A different study furthermore found that striving for financial success, a goal that might detract from need satisfaction, has a negative impact on SWB, in particular on self-actualization, vitality, symptoms of depression and anxiety.” Also note that a meta-analysis found that a materialistic orientation is negatively associated with personal wellbeing.

^{^}

 Hennecke and Brandstätter (2017), sections Slow or Fast: The Role of Goal Progress, Goals Don’t Come as Singles: The Role of Intergoal Relations, and Stay or Go: Action Crises and Goal Disengagement.

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 Sheldon and Lyubomirsky (2019), p.5.

Hennecke and Brandstätter (2017), section The Pursuit of Happiness: Consequences of Wanting to Be Happy.

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 You might also find it useful to check their three models on the topic of activity choices and lasting happiness: the Eudaimonic Activity Model, the Hedonic Adaptation Prevention (HAP) model, and the Positive Activity Model. As an illustration of their instructiveness, all three suggest mechanisms through which it may be possible to sustain elevated SWB in the face of adaptation. For instance the HAP model emphasises variety in activities to resist erosion by the hedonic treadmill.

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 The above section What determines our happiness? can provide you with some indications on the relative importance of several life circumstances and a change in them. 

To take the example of a change in country of residence, Geerling and Diener, 2020 write: “Diener et al. (2018) found that characteristics of nations were more powerful than characteristics of a person in influencing self-reported well-being”. 
In this cited Diener et al. (2018c) paper, the authors write: “Replicating and extending the earlier findings, we found that, compared with the averagely happy people, the happiest people were more likely to come from societies high in subjective well-being and social capital. To achieve very high happiness, it is helpful not only to have desirable personal circumstances, but also to live in a prosperous happy society with strong social support.”. 
A noteworthy caveat is that living in a prosperous society as a born citizen and migrating to it are very different, even if some findings indicate a rise of immigrants’ life satisfaction to the levels of the nation’s other residents. 
All that being said, a change in country of residence is plausibly not that comparable to the other life circumstances changes.

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 On this question see Diener et al. (2018a), top left of p.3, as well as Luhmann et al. (2012), in particular Table 3 summarising adaptation effects of different life events.

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 Lyubomirsky and Della Porta (2010) explain: “What is wrong with trying to attain ideal life circumstances as a prime strategy for increasing happiness? First, life circumstances are typically stable and are therefore vulnerable to the emotionally desensitising effects of hedonic adaptation (Lyubomirsky, 2009; Sheldon & Lyubomirsky, 2004, 2006a). For example, Sheldon and Lyubomirsky (2006a) found that positive circumstantial changes (e.g., receiving an unexpected scholarship or initiation into a fraternity) were associated with only a temporary boost in well-being. Second, attempting to produce changes in life circumstances can consume time, energy, or resources that a person may not have and, in some cases (e.g., a real estate downturn when one desires to move) is practically impossible. In sum, changing one’s circumstances to increase happiness is not likely to be fruitful.”

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 van Agteren et al. (2021).

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 We took many intervention effect sizes (and ideas) from this Nature article, which is the broadest and most recent academic review paper on psychological interventions to improve wellbeing we found, and whose consultation we recommend.

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 For instance, for singular positive psychology interventions in general, we didn’t include Sin and Lyubomirsky (2009) and Bolier et al. (2013) because of the existence of more recent and encompassing papers, as well as their methodological issues raised in White et al. (2019).

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 Lakens (2013) still recommends using Hedge’s g: “Although the difference between Hedges's gs and Cohen's ds is very small, especially in sample sizes above 20 (Kline, 2004), it is preferable (and just as easy) to report Hedges's gs.”

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 Faraone (2008), Table 1 (here in the case of drug treatment): “[The standardized mean difference] gives the difference between drug and placebo outcomes adjusted for measurement scale and measurement imprecision; can be translated into the probability of treated patients improving more than the average placebo patient.”

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 For instance in Heekerens and Eid (2021): “We calculated standardized effect sizes Hedge’s g to indicate the difference between the best-possible-self intervention and control conditions because the included studies used different scales to assess similar outcomes.”

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 Andrade (2020), section Interpreting the SMD.

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 Here is an example of an intuitively graspable interpretation, found in McClintock et al. (2019): “we found that [mindfulness] retreat participants reported greater well-being than control participants at post-retreat (Hedges’ g = 0.37). The size of this effect can be interpreted in several ways (see, Lambert 2013). Specifically, a Hedges’ g close to 0.4 implies that almost 4% of the variability in well-being outcomes is attributable to condition assignment (i.e., mindfulness retreat vs. control). Put differently, it is expected that about 65% of mindfulness retreat participants would have a better well-being outcome than the average control participant. Yet, another interpretation is that almost 60% of mindfulness retreat participants would experience a ‘success’ in terms of their well-being versus about 40% of control participants (see, Lambert 2013).”

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 The closer to measures of life satisfaction or positive and negative affect the better, as described in the section just below.

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 The closer to a neutral (not negative or positive activity) control group the better.

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 We favoured post-intervention measurements over follow-up ones.

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 The higher the better.

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 A few examples:

-van Agteren et al. (2021): “An overall effect size on mental wellbeing was calculated for the meta-analysis, as research points to the existence of an overarching wellbeing factor (Disabato et al., 2016)” and “In general, results for subjective (hedonic) wellbeing mirrored the findings for the general mental wellbeing scores”. In the Disabato et al. (2016) paper: “Although Hedonia and Eudaimonia have become popular within the scholarship of well-being, empirical support for their distinction is limited. Conceptualizing Hedonia and Eudaimonia as one higher order factor with multiple lower order constructs may be more appropriate than treating them as distinct constructs.”

-Lomas et al (2018) : “the concept of ‘wellbeing’ is increasingly used in academia as an overarching, multidimensional term, incorporating all the ways a person might hope to do or be well (de Chavez, Backett-Milburn, Parry, & Platt, 2005), including physical health (Larson, 1999), cognitive performance (Tang et al., 2007), and positive affect (Diener, 2000).”

-Kaftan and Freund (2018): “cognitive and affective aspects of subjective well-being [...] represent distinct lower order constructs, but also load onto a single higher-order factor of subjective wellbeing (Lucas, Diener, & Suh, 1996).”

-OECD (2013, p.51) (found in this Happier Lives Institute article): “Boarini et al. (2012) find that affect measures have the same broad set of drivers as measures of life satisfaction, although the relative importance of some factors changes.”

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 First, some review papers (despite the reservations sometimes expressed by their authors) cover many types of indicators at once, for instance:

-Zheng and Chen (2018): “a myriad of outcome measures was used in both observational and intervention studies, leading to the difficulties in synthesizing results across different studies. For example, near half of the studies used one-item question to measure happiness, which assumed that respondents understood that happiness was an overall evaluation of life, while other studies adopted well-validated questionnaires.”

-Donaldson et al. (2021): “A variety of measures were used to measure well-being. This variety reflects the lack of consensus on a universal definition of well-being in the positive psychology literature (Diener et al., 2018), which can make it challenging to compare the impact of different interventions.”

-Robinson and Eid (2017): “Most of the research that we will refer to in this chapter has used indicators of life satisfaction, and/or positive and negative affect. Note, however, that some of the studies we review have looked at other indicators, such as depression or physical symptoms.”

Second, you can see, in the column Outcome of our Data sheet, examples of meta-analyses with a computed effect size from various measures. As a case in point, Curry et al. (2018) (Table 1) use numerous outcomes covering the distinct types of wellbeing. Davis et al. (2016) go as far as including depression: “We [tested the effectiveness of gratitude interventions on] psychological well-being (measures of life satisfaction and depression were aggregated, consistent with prior reviews; e.g., Nelson, Kushlev, & Lyubomirsky, 2014).”

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 Tov (2018): “AWB [affective wellbeing] and CWB [cognitive wellbeing] are strongly correlated. [...] Nevertheless, correlations between AWB and CWB are not so strong that they could be considered redundant.”

Zessin et al. (2015): “Chen et al. (2013) analyzed the factorial structure behind subjective and psychological well-being using a bifactor model to investigate any unique and shared variance. On the one hand, they found a strong, general factor that contains the shared ground of these two concepts. On the other hand, they also found some specific factors of subjective and psychological well-being after partialling out the general well-being factor. Therefore, these two conceptualisations of well-being should be analyzed individually, whereas their commonalities should not be ignored.”

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 Solanes et al. (2021) “We initially intended to include pooled measures of SWB, but we later decided to exclude them because they were too heterogeneous. For example, Lyubomirsky et al created a composite of life satisfaction, happiness, pleasant affect and unpleasant affect by averaging their z-scores (after reverse-coding unpleasant affect), Page et al summed life satisfaction and positive affect and subtracted negative affect, or King et al, Sheldon et al, Aknin et al and Donnelly et al subtracted negative affect from positive affect (i.e., the affect balance).”

Upton and Upton (2014) (in the specific case of health related quality of life (HRQoL)): “Despite some commonalities, HRQoL and well-being should be treated as separate concepts.”

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 Diener et al. (2018a), section Measures and methods.

Clark et al. (2018), p.3 section Measuring Happiness.

Frijters et al. (2020), p.14 section Which measure is best?

Happier Lives Institute, The measurement of happiness, section 2.4 Which measures should we use?

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 Details on the calculation can be found in the C1 cell of our Results sheet.

It would arguably be more appropriate to use the number of participants for the weighting, but since this information was often unavailable, we took the number of studies as a proxy, assuming that studies with high and low numbers of participants would even out.

We included non-significant effect sizes in the calculation, based on the idea that, in an ideal scenario where all studies followed the same protocol, we could treat all results as parts of a big experiment and aggregate them without taking account of the significance of individual results. Knowing we’re not in such a scenario, our calculation still ends up putting less weight on non-significant results, as in practice the number of studies included in meta-analyses with non-significant results is often low.

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 This would allow us to put much more weight on the meta-analyses with a small confidence interval, i.e. the more “precise” ones. Unfortunately there were several meta-analyses for which we hadn’t found a confidence interval.

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 This practice of averaging effect sizes can also be found in Solanes et al. (2021), section Data extraction and selection, or Carr et al. (2021), section Meta-analysis.

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 A big limitation is that the wellbeing of participants is sometimes measured immediately after a brief participation in the intervention activities, but sometimes after many repetitions, distributed in time, of the intervention activities.

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 Once again, we would have preferred directly using the sample sizes, but this number wasn’t always available.

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 Including mixes or aggregations of these measures.

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 It was considered a mindfulness intervention in van Agteren et al. (2021), but a compassion intervention in Zessin et al. (2015), Kirby et al. (2017) and Galante et al. (2014).

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 van Agteren et al. (2021) argues: “psychological interventions are typically complex and often borrow techniques from other therapeutic paradigms, which makes it difficult to categorize ‘pure’ interventions and their subsequent impact on outcomes.” and “[it was] challenging at times to determine the precise components or the theoretical background of the intervention being studied.”

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 The RCTs included in van Agteren et al. (2021) but not in Heekerens and Eid (2021) are: Khanna and Singh (2019),  Ng (2016), Odou and Vella-Brodrick (2013), Owens and Patterson (2013) (note that this one is on children), Seear and Vella-Brodrick (2013), and Seligman et al. (2005).

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 As van Agteren et al. (2021) put it: “interpreting results of existing independent syntheses poses challenges as a result of their methodological differences. For instance, as mental wellbeing is a broad concept with differing definitions, it is important to synthesize studies that have used similar subjective measurement methods to measure wellbeing. The inclusion of psychological distress or generic quality-of-life scales as a proxy for mental wellbeing outcomes will lead to different conclusions than if only measures of mental wellbeing are included.”

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 See this interesting practice for dealing with follow-up data in Solanes et al. (2021): “If the RCT reported more than one effect size (e.g., at different follow-up times), we averaged them.”

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 Note that roughly 80% of RCTs on the efficacy of positive psychology interventions are conducted on WEIRD populations (Hendriks et al., 2019).

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 And some of our reviewed interventions have also been directly tested as a treatment option for clinical conditions, such as compassion interventions for psychological disorders including depression.

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 When two interventions had the same effect size, we put the one with the highest time efficiency score first.

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 We found the following statements:

-van Agteren et al. (2021): “[The] relatively high rates of omission in methodology and high risk of bias led to downgrading of the evidence quality for the large majority of the included intervention types.”, “While evidence for the efficacy of mindfulness and both types of PPI was high in the general population, the majority of studies were judged to have low or very low evidence quality”, “The field of wellbeing science and the evidence quality in syntheses of studies in the field will benefit from improvements in rigour. Factors contributing to the downgrading of the quality of evidence included high rates of unclear and high risk of bias, small sample sizes, lack of published protocols or trial registries, and inconsistent reporting between studies” and “For many of the interventions studied here, the evidence quality is in need of improvement”.

-Diener et al. (2017): “As with all research approaches, there are challenges with intervention studies designed to raise well-being. Challenges of real-world experimentation include creating appropriate control groups, complications with random assignment to conditions, and differential attrition between the experimental groups. In addition, there is not yet a consensus on what interventions are most likely to lead to long-term improvements in SWB. It is not known whether treatments would be more effective if they were targeted at the requirements of individual participants rather than the current one-size-fits-all approach. The current studies investigating experiments designed to raise SWB are few, based on relatively small samples, and have not examined an array of health outcomes.”

-van Zyl and Rothmann (2014) (but note that this review may not be most up-to-date): “The aim of this study was to investigate the main streams of research on happiness, the approaches/models flowing from these philosophies and the methodology of happiness interventions. The results showed that there is still little consensus among researchers regarding the conceptualisation of the concept happiness, as well as the methodological components for interventions.”

-Bergsma (2020) (who holds the most radical stance we encountered, but whose position doesn’t seem influential in the field): “Two claims have been central in the marketing of positive psychology interventions and their role in the pursuit of happiness. The first selling point that the intentional pursuit of happiness is made easy thanks to scientific studies is overdone, which is recognized by experts such as Lyubomirsky. The second marketing idea is that positive psychology offers a vast improvement in happiness advice, thanks to the scientific rigor and quantitative research designs. This claim has not received empirical support, and there even is an indication of a decline in the effectiveness of following happiness training over time. [...] Claims about having found the truth on happiness advice is overdone considering the existing data.”

See also this EA Forum discussion that touches on the subject.

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 Bergsma (2020): “Perhaps it is too early to tell, but it seems that positive psychology has stumbled upon the dodo verdict.”. Also in Davis et al. (2016): “Lyubomirsky and Layous (2013) concluded that engaging in any regular activities involving self-discipline seems to promote psychological well-being.”

See Marcus et al. (2014) (initially found here) for a recent meta-analysis exploring the topic of the dodo bird verdict in the case of psychotherapies.

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 Kvarven et al. (2020). We found this paper here.

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 Schueller and Parks (2014): “PPIs can lead to reliable boosts in wellbeing, yet these benefits are smaller when provided as self-help resources (Sin & Lyubomirsky, 2009).”

Fischer et al. (2020): “Overall, self-guided activities [...] appear effective, but not as effective as in-person or group-based interventions.”

Donaldson et al (2021): “Although individualized interventions tended to show greater effects than self-help or group interventions across meta-analyses (Sin and Lyubomirsky, 2009; Weiss et al., 2016; Carr et al., 2020), three out of four of the most promising PPIs were online and were all self-administered with success. [...] A combination of automated content supplemented by live expert or peer support can also be considered.”

van Agteren et al. (2021): “Group-based interventions reached the highest effect size compared with individual and technology-based interventions in the general [...] population.”

In general, there is a rather solid evidence base in favour of the efficacy of self-help for psychological outcomes: “we found that [the self-help method for] delivering psychotherapy is generally well evidenced. In total, we found over fifty randomised controlled trials examining the effects of self-help (guided and pure) that demonstrate its efficacy on multiple metrics. Most importantly for this report, multiple trials examine the effects of self-help on subjective well-being.” (Charity Entrepreneurship Research Report: Mental Health - Self-Help, 2020)

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 Similar to van Agteren et al. (2021): “the overall degree of overlap in confidence intervals between intervention types meant no conclusive judgement could be made about the superiority of one type over the other.”

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 That is for instance what the positive activity model posits, described in Sheldon and Lyubomirsky (2019), p.8.

See also:

Bergsma (2020): “Miller et al. suggest [that] we should focus less on what works, and more on how the pursuit of happiness works for whom.”

D’raven and Pasha-Zaidi (2014): “Clearly, the fit between PPIs and individuals is not the same for everyone, and clinicians are advised to attend to questions of fit, preference, timing, personality style, and culture when administering PPIs with clients (Parks & Biswas-Diener, 2014).”

Schueller (2012) describes an example of differential personality fit, in this case between extraverts and introverts: “Extraverts benefited more from the gratitude visit and savoring exercises, whereas introverts benefited more from the active-constructive responding, signature strength, and three good things exercises. [...] These studies provide support for the notion that introverts and extroverts may benefit from pursuing different strategies to promote happiness.”

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 A close approach is described in Parks et al. (2013): “[A model] for accommodating individual differences in preference and responsiveness to specific exercises is the approach taken by Parks (2012). Each participant samples a variety of exercises, then in the time following the intervention, chooses one or two to continue practicing. In this way, participants are exposed to several techniques and have the opportunity to select what they continue to practice, but do so having tried each one rather than relying on their initial impressions of what may or may not be helpful for them. In essence, flexibility is crucial for the success of happiness-increasing strategies.”

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 “The present research illustrates that although neuroticism moderates the sustainability of positive intervention effects, encouraging continuance of positive activities may produce more lasting effects.”

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 One meta-analysis (Barton and Pretty, 2010) also specifically found moderate benefits on moods (effect size of d = 0.54) of green exercise, i.e. exercise in the presence of nature.

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 van Agteren et al. (2021): “our evidence is consistent with the use of higher-intensity psychological interventions to facilitate the reinforcement of practices in everyday life.”, and “While the review did not find a clear linear dose–response effect, with more exposure leading simply to better treatment outcomes, the results do indicate that more intense interventions seem to lead to more pronounced changes, particularly in the general [...] population. These results need to be placed in the context of the overlap in confidence intervals between intensities, which means that it is not possible to definitively state that higher-intensity interventions provide superior results.”

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 McClintock et al. (2019), p.1.

But mindfulness also includes informal practices. Querstret et al. (2020): “Formal practice occurs through taught meditative techniques (e.g., body scan, mindful movement, mindful yoga) both in session and daily (as homework); whereas informal practice - which involves developing awareness of body sensations, thoughts, emotions and sensory input (sights, scents, sounds) - is practiced via day-today activities like eating a meal, brushing teeth and walking.”

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 Lomas et al. (2018), p.2. Also p.11: “a common theoretical position is that mindfulness may enhance mental health in the following way: (a) mindfulness involves introspective practices that enhance attention and awareness; (b) their development improves emotional regulation (including abilities such as reperceiving); and (c) emotional regulation is a meta-skill that subserves multiple wellbeing outcomes”.

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 MBSR and MBCT were the most commonly studied interventions in the reviewed meta-analyses, which in some cases also included loving-kindness (or “metta”) meditation, but not in others.

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 Querstret et al. (2020): “further research is warranted with RCT designs to assess the most meaningful moderators against each other (e.g., does mode of delivery have a significant impact?).”

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 For instance in Querstret et al. (2020): “All of the studies assessing quality of life/well-being as an outcome evaluated a MBSR [and not a MBCT] intervention.”

Also, from Lomas et al. (2018): “MBSR is the most well-established and -tested MBI [Mindfulness-Based Intervention].”

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 Querstret et al. (2020): “aspects of implementation relating to ‘duration of the intervention (weeks)’, ‘intensity of training (minutes per week)’ or ‘total training (weeks x hours)’ showed some associations. Generally, longer interventions with more training time were associated with increased ‘quality of life/well-being’.”

Khoury et al. (2017): “At the end of treatment, the average pre–post effect size of clinical outcomes was positively moderated by treatment hours (n = 25; β = .01, SE = .01, p < .05), and assigned home practice (n = 18; β = .01, SE = .01, p < .05).”

Galante et al. (2021): “Our weak finding that longer courses may be slightly less beneficial was unexpected, although it could be a result of multiple testing and residual confounding. Other reviews assessing course duration have not found this to be an important effect moderator. Combined, this evidence suggests that MBP courses do not have to be long to be effective.”

Bartlett et al. (2019): “it is not yet possible to derive a minimum required dose for positive effect from the current evidence base.”

McClintock et al. (2019): “Future investigations might also seek to clarify optimal dosage of mindfulness practice (i.e., duration and frequency) and how the effects of retreats, which offer an extended period of intensive practice, compare to the effects of less-intensive daily practice.”

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 Howells et al. (2016), found in van Agteren et al. (2021).

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 Krusche et al. (2012), Querstret et al. (2017) and Querstret et al. (2018), found in Querstret et al. (2020).

An example of a MBSR curriculum can be found here.

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 Lever Taylor et al. (2014), found in Querstret et al. (2020).

“The book starts with an introduction, followed by eight intervention chapters each based on the equivalent session in the therapist-led MBCT course. Readers are asked to read one intervention chapter a week and to practice a series of 20-30 minute mindfulness practices from the book's accompanying CD. The first four intervention chapters teach readers to attend to their internal and external world, and to use the ‘Three-minute Breathing Space’ practice to ground themselves when they feel stressed. The remaining four chapters provide practical ways to see thoughts as mental events and to cultivate an attitude of acceptance, compassion and empathy.”

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 Spadaro and Hunker (2016), found in Querstret et al. (2020).

The book wasn’t actually at the heart of the intervention, but was sent to participants, along with the CD Mindfulness for Beginners, to reinforce continuing the mindfulness meditation practices after they had followed an online intervention based on Kabat-Zinn’s MBSR Program, and before a last follow-up measurement.

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 Sources: Mental Health Resources by Ewelina Tur, Virtual Mental Health Resources by EA Mental Health Navigator and this EA Forum post by John Halstead.

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 Sources: Mental Health Resources by Ewelina Tur, this EA Forum post by John Halstead, this 80,000 Hours article.

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 Source: This EA Forum comment.

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 Mainly Week 1’s section on Mindfulness.

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 This 2022 broad systematic review of meta-analyses, found here, can also provide an up-to-date view on the empirical status of mindfulness (note that the effect size of 0.21 they find for wellbeing is based on one meta-analysis on women with breast cancer), including a discussion of publication bias and risk of bias (section Potential sources of bias).

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 Alarcon et al. (2013).

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 Loveday et al. (2018).

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 van Agteren et al. (2021): “Example domains are: love, hobbies, employment, physical and mental health.”

Loveday et al. (2018): “Some researches provide three themes: personal, professional, relationship. Others provide four themes: social, health, academic and career and others eight themes: romantic, hobbies, family, friendship, community, health, career and free topic.”

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 Heekerens and Eid (2021): “effects are not larger [...] in studies using an imagery component.”

In Loveday et al. (2018) the difference was in terms of mental imagery ability: “[the hypothesis that individuals with higher mental imagery ability would have superior results] was not supported, suggesting that the BPS can be an effective intervention irrespective of mental imagery ability.”

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 Loveday et al. (2018): “There does not [...] appear to be strong justification for repeat schedules with some studies using a daily administration and others weekly administration. [...] Further studies are needed before it can be determined whether weekly or daily dosage of the BPS would achieve superior results.”

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 Loveday et al. (2018): “In examining the BPS research there is no justification provided for the choice of themes given to participants who repeat the activity, rather researchers simply state the themes that they used.”

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 Carrillo et al. (2019): “As to the duration of the intervention, no differences were found in length and intensity, but a marginally significant difference emerged in the magnitude of the intervention. This result suggests that shorter practices (in total number of minutes) may lead to more benefits from the BPS. However, these results should be further explored.”

Heekerens and Eid (2021): “effects are not larger for more intense administrations of the intervention.”

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 Carrillo et al. (2019): “whether administered [...] online or face-to-face [...] similar outcomes seem to be produced.”

Heekerens and Eid (2021): “As mentioned, results do not support any of our moderator hypotheses. However, additional analysis results reveal that online administrations of the best-possible-self intervention had no effect on positive affect. This finding is in sharp contrast to results from one experimental study that suggested that online and in-person administrations are equally effective. [...] Finally, results do not allow for firm conclusions regarding [...] how the exercise should be delivered to achieve optimal results.”

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 Heekerens and Eid (2021): “For positive affect, effects seem to remain stable 30 days after the intervention and disappear 60 days after the intervention.”

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 And you can find additional ideas here.

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 Zessin et al. (2015).

See also Kirby et al. (2017), section Defining Compassion for a discussion on its different definitions.

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 Zessin et al. (2015).

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 van Agteren et. (2021).

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 Not in Ferrari et al. (2019): “Although there is a conceptual overlap, mindfulness-based interventions including the loving-kindness meditation were not the focus of the current review and are reviewed elsewhere (i.e., Galante et al. 2014; Zeng et al. 2015).”

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 This linked book presented as a “step-by-step explanation of the systematic practice”, which we haven’t reviewed and which may not be completely secular, is mentioned in Zeng et al. (2015): “the philosophy that gaining happiness from good interpersonal relationships is also an important idea of LKM (Sujiva, 2007).”

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 Galante et al. (2014).

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 Kirby et al. (2017): “A further limitation of this review was that we were unable to assess for the effect of specific moderators (e.g., gender, dosage, intervention delivery) or intervention components largely due to the small number of studies per outcome.”

Zeng et al. (2015): “the structure of interventions varies in many aspects, and many details were not reported by every study; therefore, it is hard to compare studies across study levels.”

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 Zessin et al. (2015): “Regarding the study characteristics, the analysis showed a significant effect of female proportion [...]. In the samples, more females strengthened the relationship between self-compassion and well-being.”

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 Zeng et al. (2015): “[An] important component in intervention is the disclosure or didactic component during courses, which not only consists of meditation guidance but also covers relevant Buddhist philosophy or ideas, such as the relationship between oneself and others or why it is important to be compassionate to others.”

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 Zeng et al. (2015): “whether more intensive [loving-kindness] meditation practice in interventions will lead to better results in the long term remains unclear.”

Galante et al. (2014): “A trend toward more significant results in long interventions [more than one week] compared to short interventions was not detected. Longer or more intensive interventions may be required. Some benefits appear to be restricted to those participants who practice the most. Several studies found a dose–response gradient in the KBM arm.”

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 Kirby et al. (2017), section Study Characteristics.

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 Neff and Germer (2013).

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 Gilbert (2014), Gilbert (2010).

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 Leaviss and Uttley (2015).

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 The co-author of this book, Chris Irons, set up the organisation Balanced Minds that provides (expensive) courses, an app, and free self-help resources on compassion.

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 Goldin and Jazaieraepälä (2017).

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 See also this post for an example of a EA-inspired LKM.

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 Buecker et al. (2020): “we found that neither the degree of sociality, nor the intensity of the physical activity or the exercise modality (aerobic vs. anaerobic) moderated the relation between physical activity and SWB”, “the intensity of physical activity did not significantly moderate the relation between physical activity and SWB, suggesting that the effects of physical activity on well-being were similar for high, moderate, and light intensity.” and “the relation between physical activity and SWB is independent of the

physical activity characteristics under investigation in this meta-analysis.”

Zhang and Chen (2018): “There might not be an optimal type or intensity of PA in the relationship between PA and happiness.”

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 Buecker et al. (2020): “Our results also indicate that physical activity is beneficial for one’s SWB independent of the prior fitness level of the sample.”

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 Zhang and Chen (2018): “the dose–response relationship between PA and happiness remains largely unknown, especially given the limited evidence by intervention studies” and “More research is necessary to determine the optimal dose and type of PA for gaining the benefits of happiness, and explore the pathways through which PA would possibly affect happiness.”

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 Zhang and Chen (2018): “Richards et al. (2015) found that there was a positive dose–response relationship between PA and happiness among citizens in 15 European countries. Compared with inactive people [0–9 minutes of physical activity], the odds ratio of being happy was 20, 29, and 52% higher for people being insufficiently active [10–149 min], sufficiently active [150–299 min], and very active [300+ min], respectively.”

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 Zhang and Chen (2018): “there seems to be a threshold effect for the relationship between PA and happiness. Several cross-sectional studies found that there was no difference in happiness levels between active individuals (150–300 min moderate to—vigorous PA per week) and very active individuals (>300 min moderate to—vigorous PA per week). This was further supported by one RCT which compared the moderate volume of PA intervention (150 min aerobic exercise per week) with the high volume of PA intervention (300 min aerobic exercise per week) and found no difference in the change of happiness between two groups.”

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 Zhang and Chen (2018): “Our findings suggest that PA frequency and PA volume are essential factors in the relationship between PA and happiness.”

In the four cross-sectional studies they cite that found a positive association between PA frequency and happiness, only measures of frequency, and not volume, are collected, so it’s not possible to know whether there is a specific role of frequency independent of volume. It is because we should expect that participants that report a higher frequency, spend more exercise time in total, than those that report a lower frequency.

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 Zhang and Chen (2018): “even a small change of PA makes a difference in happiness. Studies showed the significant difference in happiness levels between doing exercise 1 day per week and none per week. As little as 10 min PA per week might greatly increase the odds of being happy.”

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 Conn et al. (2011): “interventions to increase PA should emphasize behavioral components such as self-monitoring, stimuli to increase PA, rewards, behavioral goal setting, and modeling PA behavior in standardized interventions delivered to individuals.”

Howlett et al. (2019): “Studies that included the behavior change techniques ‘Biofeedback,’ ‘Demonstration of the behavior,’ ‘Behavior practice/rehearsal,’ and ‘Graded tasks’ showed larger effect sizes at postintervention than studies that did not.”, “Studies that included ‘Action planning,’ ‘Instruction on how to perform the behavior,’ ‘Prompts/cues,’ ‘Behavior practice/rehearsal,’ ‘Graded tasks,’ and ‘Self-reward’ showed larger effect sizes at follow-up than studies that did not.” and “The most frequently used behavior change techniques were ‘Goal setting (behavior)’ (22 studies) and ‘Social support (unspecified)’ (20 studies). [...] This review showed that interventions aiming to increase physical activity in healthy inactive adults are effective in promoting behavior change and behavior change maintenance.”

See also Knittle et al. (2018) on interventions increasing motivation for PA, and Ashford et al. (2010) and Williams and French (2011) on interventions for changing PA self-efficacy.

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 Gable and Haidt (2005) defined it as “the study of the conditions and processes that contribute to the flourishing or optimal functioning of people, groups, and institutions.”

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 van Agteren et al. (2021).

See Stone and Parks (2018) for a review of PPIs, including their benefits and critiques. Note that the field and research in positive psychology is subject to criticisms. For instance van Zyl and Rothmann (2022), as well as Ciarrochi et al. (2016), section Criticisms of Positive Psychology, mention some, and Brown et al. (2018) is dedicated to an academic critical examination of the field. The book Psychology applied to modern life (found here), Chapter 16, section 5, Positive Psychology: Problems and Prospects, also points to a few academic criticisms.

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 For example, according to Manicavasagar et al. (2014), the program from the positive psychology website for teenagers Bite Back spans nine domains: gratitude, optimism, flow, meaning, hope, mindfulness, character strengths, healthy lifestyle, and positive relationships. 

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 Hendriks et al. (2020) found higher effect sizes for group then individual then self-help delivery formats, for interventions lasting less than 8 sessions or weeks, and for non-western participants, but all these results were non-significants: “Explorative subgroup analyses revealed mainly no significant results, indicating that we could not identify study or intervention characteristics that led to more or less effectivity of MPPIs.”

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 Huffman et al. (2011): “Each week, participants would complete all aspects of a positive psychology exercise in a single day; the choice of this timing was based on evidence that such clustering of intervention activities is more effective than completing activities over a longer time frame. We chose to have participants complete exercises on a weekly basis, rather than more frequently, to make the intervention more feasible for subjects who may have limited energy or time. In addition, some positive psychology trials have found weekly exercises to be more effective than daily exercises in improving positive affect, possibly due to loss of novelty and ‘hedonic adaptation' when tasks are completed every day.”

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 We checked the public availability of the program used in every study included in van Agteren et al. (2021) and Hendriks et al. (2020) with one of the terms “self-help”, “online”, “web”, “book” in its title. Here you can find a few well-presented program descriptions to get a sense of their content: Table 1 of Cohn et al. (2014), Table 1 of Drozd et al. (2014), Table 1 of Feicht et al. (2013), Table 1 of Ivtzan et al. (2016), Table 1 of Koydemir and Selışık (2015), the Enhance course (you can download the website freemium version as a Word document at this link) described in Table 1 of Kushlev et al. (2017), the PERMA-based program (and close to the Penn Resilience Program) described in Table 1 of Neumeier et al. (2017), Table 1 of Page and Vella-Brodrick (2013), and the Well-Being Therapy intervention described in Table 1 of Xu et al. (2019). Proyer et al. (2013) test a character strengths-based program, of which this website seems to be a current version (at the time of writing, it’s possible to follow the program online for free, which is under scientific evaluation).

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 In addition to the books and courses presented, you can use apps:

-SuperBetter encourages the practice of positive activities in the form of a game. Using the app daily for 10 minutes appears to have a positive effect on mental health (Roepke et al., 2015).

-Happify (download links), whose chief scientist was happiness interventions researcher Acacia Parks, proposes programs inspired by positive psychology with quick games and activities.

We didn’t include them as main recommendations, though, because after a very quick use test of these two apps, we found several of their activities somewhat shallow and the user experience not the best.

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 Reading the book and completing its exercises has been shown, in a RCT by Parks and Szanto (2013), to be effective at increasing the life satisfaction of college freshmen, and a little more in comparison to a CBT self-help book.

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 A lot of similar techniques are covered in the book Flourish by Martin Seligman, but a glance through its content gave us the impression that it is less practice-oriented. Seligman also wrote a clinical manual that contains practical applications (with e.g. worksheets) of positive psychology principles as a whole therapy.

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 All the content in this paragraph comes from Schutte and Malouff (2019), section Introduction.

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 Schutte and Malouff (2019): “ [The meta-regression assessing the association between effect size for life satisfaction and duration of the intervention was] nonsignifcant. The association between the duration of the intervention and effect size had a slope of − 0.01, SE = 0.02, 95% CI [− 0.05, 0.03], p = .56.”

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 See here for the PDF format of Haidt (2002).

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 D’raven and Pasha-Zaidi (2014), section Acts of Kindness.

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 Curry et al. (2018), section Study characteristics.

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 Stone and Parks (2018), section Kindness.

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 Aknin et al. (2013), found here. See Hui (2022) for a review covering the most recent evidence on the topic, as well as Moche and Västfjäll (2021), introductory section.

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 Curry et al. (2018): “we did not find evidence for associations between [proportion of male participants, average age of the sample, type of participant (typical, socially anxious), type of intervention (acts of kindness, prosocial spending, other), type of control condition, outcome measure] and effect size.”

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 Curry et al. (2018): “there has been little systematic investigation of whether different people benefit more from performing acts of kindness under different conditions. And studies have not systematically varied the type of recipient, for example family, colleague, friend, stranger.”

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 Ko et al. (2019): “Our findings support past research demonstrating that both performing and recalling acts of kindness promote well-being. [...] the effects on well-being were similar whether individuals performed acts of kindness or simply recalled them, and were not strengthened by doing both activities. [...] individuals who seek to efficiently improve their well-being may be just as successful by remembering kind acts that they have performed in the past as actually doing more such acts in the future. Of course, we do not suggest that people should stop being kind to others. Indeed, happiness seekers should continue to act prosocially towards others to create more memories of these acts. Recollections such as giving one’s grandparents a hug, buying lunch for one’s coworker, and picking up one’s younger sibling from school are some actual examples that promoted our participants’ wellbeing. Our data suggest that, when it comes to boosting well-being over 1 to 2 days, these recollections are just as effective as performing new acts of kindness.”

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 Davis et al. (2016), introductory section.

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 Renshaw and Olinger Steeves (2016), section Gratitude in youth and schools.

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 Allen (2016), section What is Gratitude?

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 Cregg and Cheavens (2021): “Research suggests gratitude interventions—designed to increase appreciation of positive qualities, situations, and people in one’s life—may improve psychological well-being.”
Davis et al. (2016): “gratitude interventions might help people defy the so-called hedonic treadmill. Namely, most people tend to return to a baseline level of happiness following positive or negative events, but some initial evidence has suggested that gratitude activities may cause long-term shifts in life satisfaction.”

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 For instance in Carr et al. (2021), section Interventions, it was the positive psychology intervention whose meta-analysis included the most studies (79).

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 Davis et al. (2016): “Although we do not believe the potential of gratitude interventions has been fully realized, enthusiasm for gratitude interventions should be tempered until longer, more-powerful interventions that have demonstrated stronger evidence of efficacy.”

Dickens (2017): “those expecting huge and lasting gains, or “life-changing” outcomes from the activity, are likely to be disappointed, especially depending on what outcome variable they are interested in improving. Although I believe psychologists may understand that small effects are likely, I am not sure if self-help authors or writers in popular magazines communicate this to their audiences but rather tout gratitude as an easy fix.”

But maybe it’s possible for an individual to use gratitude methods more effectively and get a higher effect.

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 Davis et al. (2016): “we hypothesized that groups or expressions of gratitude might work better than journals or lists because they involve an interpersonal element. [...] Interventions that used expressions of gratitude had an effect size to similar that for interventions that used journals/lists. So this hypothesis was not supported.”

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 Dickens (2017): “Findings indicated that the gender makeup of the sample did not appear to influence the magnitude of the effects.”

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 Davis et al. (2016): “there were enough studies using journals or lists to examine a potential dose effect. Neither days nor minutes of participation moderated the effect size with psychological well-being.”

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 Dickens (2017): “Several predicted moderators—knowledge of study aims, peer-reviewed versus other types of work, type of gratitude intervention, culture, frequency of intervention (daily vs. weekly), the duration of the intervention, type of effect size calculation—could not be examined, as the number of effect sizes was sometimes too small, and at times there was no variability within certain meta-analyses.”

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 For brief overviews see Allen (2016), section Gratitude Interventions and Skrzelinska and Ferreira (2022), section Gratitude interventions.

Dickens (2017), Table 1, Gratitude interventions, lists the intervention they included in their meta-analysis.

The most studied are gratitude journaling and gratitude letter:

Dickens (2017): “Seventeen studies were conducted over a 1-week or 2-week intervention period, 11 ranged from 3 to 5 weeks, and 10 studies examined interventions lasting 6 to 12 weeks. Thirty studies used either a daily or weekly counting blessings induction, five used a gratitude letter (some with a related gratitude visit), and the remainder involved some other kind of grateful thinking or writing induction.”

Davis et al. (2016): “The most common strategy to promote gratitude has been to have participants regularly engage in brief activities designed to cultivate a sense of gratefulness. For example, in their seminal article, Emmons and McCullough (2003) had people list five things for which they were grateful several times per week. Building on this concept, others have had individuals cultivate gratitude internally and then express it in a letter or verbally.”

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 The book is mentioned in Dickens (2017): “Some [self-help books] are written by psychology researchers and built on empirical research (e.g., [Gratitude Works! by Emmons] [...]).”

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 van Agteren et al. (2021): “The total number of studies investigating PPIs in the general population was large and overall the evidence quality was graded as high.”

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 Koydemir et  al. (2021): “There were significant differences between interventions that employed technology and those that were delivered traditionally. The interventions that did not use technology had larger effects on average (d = 0.32, p = .000) than those that relied on technology (d = 0.17, p = .000). In other words, the interventions using technology were less effective than interventions employing traditional face-to-face methods.”
“The results showed that [...] as age increased, the effect size for positive psychological interventions decreased. As expected, duration of intervention was also a significant predictor, with longer interventions having a stronger effect.”

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 Parks and Schueller (2014) has chapters reviewing savouring, meaning and humour interventions.

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 You can find more practice ideas here or in this Clearer Thinking exercise.
A savoring intervention is tested in Hurley and Kwon (2012), Palmer and Gentlzer (2018), Smith and Bryant (2019) and Bryant et al. (2021) (the last two on older adults).

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A gift of time intervention is tested in Gander et al. (2013).

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 A humor-based intervention is tested in Wellenzohn et al. (2016a), Wellenzohn al. (2016b) (see their Table 1 for ideas of activities) and Crawford and Caltabiano (2011).

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 We haven’t found resources you can directly apply, but this is the site of the organization that promotes meaning-focused training and therapy. Psychologist Paul Wong, who seems to be the main promoter of a meaning-centered approach, briefly describes some exercises here.

A meaning intervention is used in Gander et al. (2016) (here are the instructions of the exercise, line “Meaning”) and van der Spek et al. (2017).

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 We haven’t found resources you can directly apply, but you can check the exercises of the linked pilot program (they’re referenced in their Figure 2, p.80): Treasure chest p.106, Breathing together p.110, Thin spaces p.113, Legacy p.116, Gratitude p.119, Hidden compartment p.122.

A sacred moments intervention is tested in Goldstein (2007).

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 Howell and Passmore (2019), section Introduction.

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 Howell and Passmore (2019), section Conceptualizing ACT as a Positive Psychological Intervention.

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 At least when ACT is compared to CBT.

Ruiz (2012), Table 6. The researcher writes:  “Potential moderator variables (e.g., treatment format, type of problem, number of sessions, age, gender, or publication year) did not account for significant variance.”

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 To get an idea of what such ACT work would look like, you can check for instance Table 1 of Viskovich and Pakenham (2019), Table 1 of Levin et al. (2016) or Table 2 of Buhrman et al. (2013).

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 Potter et al., 2021. But this is only a feasibility RCT on carers of people with multiple sclerosis. We also found evidence in favour of the book Living Beyond Your Pain, tested on people with chronic pain (Johnston et al., 2010 ; Throsell et al., 2011).

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 van Agteren et al. (2021): “CBT is currently the most empirically supported and practised therapeutic approach (David et al., 2018).”

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 Powell et al. (2013): “In theory, an approach using the principles of cognitive behavioral therapy (CBT) to encourage more healthy patterns of thinking and behavior may offer an individual-level intervention to promote positive mental health.”

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 Powell et al. (2013): “In order to investigate the consistency of the treatment effect, subgroup analyses based on age, gender, psychiatric history, previous use of CBT, level of anxiety, and level of depression were prespecified in the protocol. [...] The treatment effect was very consistent across subgroups.”

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 King et al. (2017): “We conducted a meta-analysis of studies in which participants were randomised to receive the same treatment either through self-help or through a therapist. [...] We found no difference in treatment completion rate and broad equivalence of treatment outcomes for participants treated through self-help and participants treated through a therapist. [...] All completed randomised controlled trials (RCTs) that compared one-on-one therapist-delivered and self-help (internet or bibliotherapy) forms of CBT [...] were included.”

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 moodgym has been found effective in Hoifodt et al. (2013) and Powell et al. (2013). A course that seems close in content is Living Life to the Full, the most recommended course by the NHS.

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 Parks and Szanto (2013). But note that the book was tested on students who on average reported moderate depressive symptoms.

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 Kuykendall et al. (2015), section Conceptualization of Leisure Engagement and Subjective Well-Being.

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 Kuykendall et al. (2015), section Relation Between Leisure Engagement and Subjective Well-Being.

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 Kuykendall et al. (2015): “Treatment duration was a significant predictor of the effectiveness of the leisure intervention. Total intervention hours was also a significant predictor of the effectiveness of the leisure intervention.”

But too much leisure is maybe not the best either. Lee et al. (2019), using panel data from a national survey conducted in South Korea, found the following: “We found that weekday and holiday leisure quantities had significant curvilinear [or inverted U-shape] relationships with leisure satisfaction and happiness. [...] [For leisure satisfaction,] leisure satiation occurred when people had more than 6.56 h of weekday leisure and 5.79 h of holiday leisure. The leisure satiation was also identified in the relationship between weekday leisure quantity and happiness. [...] happiness started to decline with more than 3 h of leisure time during weekdays and the decline was further accelerated after around 6 h of leisure participation. These findings were consistent with previous studies that excessive leisure participation deteriorated leisure satisfaction and SWB.”

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 Kuykendall et al. (2015): “Hypothesis 8 predicted that leisure engagement would be more strongly associated with SWB for retired samples than for working samples. Results are presented in Table 14. The effect size was larger for retired samples, using both the inclusive proxy samples and the explicitly retired samples than for working samples, supporting Hypothesis 8.”

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 Kuykendall et al. (2015): “to be included, the leisure intervention had to have the goal of enhancing overall leisure domain experiences, not simply improving leisure by exposing individuals to or enhancing a single leisure activity (e.g., a swimming intervention). A common example of an intervention that meets the criteria is a leisure education program, which typically involves an educational component designed to familiarize participants with a wide range of potentially satisfying leisure experiences and an experiential component that actively involves individuals in such activities.”

Descriptions of leisure programs can be found in Searle et al. (1995), section Leisure Education Intervention, Janssen (2004), section Experimental Procedure, García-Villamisar and Dattilo (2010), section Leisure programme for people with autism spectrum disorder, and Desrosiers et al. (2007), section Experimental Program: Leisure Education Program, or more systematically described in this book.

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 The program in García-Villamisar and Dattilo (2010), for which they found an effect size of 3.12, lasts 12 months with 2 hours of leisure time five days a week.

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 The ideas of the last two paragraphs come from Kuykendall et al. (2015), section Measurement of Leisure Engagement.

The superiority of diversity and frequency over quantity is in part confirmed in the section Measuring leisure engagement: “Consistent with our argument that diversity and/or frequency measures are likely more effective at tapping into the need-fulfilling properties of leisure than are quantity measure of leisure, the results of our meta-analysis revealed that the relation between leisure engagement and SWB is much stronger when researchers use measures of diversity and frequency rather than measures of quantity. These findings should be interpreted cautiously because the number of quantity measures was quite low and interrelations among moderators variables may be a concern. However, our current findings support the use of frequency and diversity measures of leisure engagement when examining the relation between leisure engagement and SWB.”

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 The list is in the Supplemental Material (the docx file).

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 Scott et al. (2021), section Evidence on the relationship between sleep and mental health.

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 Scott et al. (2021): “The concept of sleep quality can also be subjective; however, broadly speaking, sleep quality consists of sleep continuity (e.g., sleep onset, sleep maintenance, and number of awakenings) and daytime impact (e.g., the extent to which the person feels refreshed on waking and throughout the day).”

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 Scott et al. (2021), section The present review: an interventionist approach to causation.

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 Scott et al. (2021): “On average, the 72 interventions that successfully improved sleep quality had a statistically significant, medium-sized effect on subsequent composite mental health outcomes.”

Also: “Studies that found significant effects of the intervention on sleep quality reported larger effects on subsequent composite mental health, than studies that did not find a significant effect of the intervention on sleep quality, a difference that was statistically significant. This finding strengthens the notion that improvements in sleep are behind improvements in mental health.”

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 Scott et al. (2021): “meta-regression revealed a statistically significant dose–response effect for the association between the effect of interventions on sleep quality and the effect on subsequent mental health outcomes, suggesting that greater improvements in sleep led to greater improvements in mental health.”

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 Scott et al. (2021) confirm that the positive effects of CBT-I on mental health are explained by improved sleep: “There were no significant differences in the effect of improved sleep quality on mental health between CBTi interventions including modules addressing processes associated with mental health, relative to those that did not. This finding suggests that it is the beneficial effect of improved sleep quality that confers improvements in mental health rather than the inclusion of modules that target processes associated with mental health commonly seen in CBTi protocols.”

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 The interventions (only five) included in the other reviewed meta-analysis by Gwyther et al. (2022) were sleep hygiene, assisted sleep, sleep recovery, sleep extension and a multicomponent intervention. See the Description of interventions sheet for their description.

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 Scott et al. (2021): “Furthermore, interventions that were delivered face-to-face by a clinician or therapist were associated with significantly larger effects on mental health, than those that were self-administered by participants.”

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 But the evidence is only on depression and anxiety: Espie et al. (2014), that is included in the meta-analysis we reviewed by Scott et al. (2021), and the research mentioned on Sleepio’s website.

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 McMahan and Estes (2015): “From this theoretical perspective, the primary function of positive emotions is to facilitate and maintain approach-oriented behavior and engagement in activities that were evolutionarily adaptive. The experience of positive emotions in many natural environments was likely adaptive throughout the majority of our evolutionary history because these emotions would motivate approach behaviors aimed at the acquisition of resources that contributed to survival (e.g. food, water, shelter, raw materials). As a result, the primary emotional response to natural environments that signal the presence of or access to evolutionarily significant resources would be increased positive affect”. Other possible theories explaining the positive effects of nature on well-being can be found in their section Theoretical foundations.

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 McMahan and Estes (2015):  “For example, Mayer and colleagues examined positive and negative affect in a group of students who spent 15-minute walking in nature vs. a group of students who spent 15-minutes walking in an urban area. Similarly, Berman and colleagues examined positive and negative affect in a group of participants who were exposed to a series of photographs depicting natural environments vs. a group who were exposed to a series of photographs depicting urban environments.”

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 McMahan and Estes (2015): “the current study indicated that people reap additional benefit from being out in real nature when compared to being exposed to simulations of nature. However, exposure to virtual nature still produced a substantial increase in positive affect, indicating that viewing nature indirectly through various types of media may be an effective means to improving well-being. This finding would seem to be particularly relevant to people who do not have easy access to natural areas, such as those who live in major urban centers or those who have functional limitations that prevent them from venturing out in nature. For these individuals, exposure to simulated nature may be one way to capitalize on the benefits of nature without actually being in nature.”

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 McMahan and Estes (2015): “contact with managed nature and wild nature produces similar effect for emotional well-being. Perhaps this is due to the fact that many managed natural environments, such as urban green spaces and arboretums, are designed to mimic those characteristics of wild nature that people find appealing, aesthetically pleasing, and restorative. In result, managed nature may serve as effective substitute for wild nature, by design.”

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 For example Webber et al. (2015) (found in Pritchard et al. (2020)) surveyed allotment gardeners who were spending on average around 8 hours per week on their allotment.

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 McMahan and Estes (2015): “the majority of the studies included in this meta-analysis assessed emotion at a single point in time directly after exposure to nature. Future research should directly address the duration of the positive effects of exposure to natural environments on emotional well-being over more extended periods of time.”

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 McMahan and Estes (2015): “Results of these analyses indicated that [...] percent female of sample [...] did not moderate the effect of nature on positive affect. In contrast, mean age of sample [...] moderated the effect of nature on positive affect, with larger effect sizes observed in those studies using older samples.”

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 McMahan and Estes (2015): “Notably, each of the studies included in the current meta-analysis used only brief exposures to natural environments, indicating that contact with nature provides benefit even in small doses. Incorporating brief ventures in nature into one’s daily routine may thus be one relatively easy and enjoyable way to achieve sustainable increases in SWB.”

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 Some speculative ideas are using videos from this Youtube channel, following Google Earth’s Great Hikes Around the World, or even playing a contemplative video game with an immersive nature environment.

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 Tulloch et al. (2018), section Introduction.

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 Knobben (2013), section Yoga in improving mental health.

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  Knobben (2013), section Yoga in improving mental health: “A more in depth explanation of the effects of yoga can maybe be found in the working processes of mindfulness. Yoga shares in common with mindfulness, the meditative/contemplative practice and emphasis on focused attention, reduced extraneous external stimulation, controlled breathing, and relaxation.”

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 Out of the three meta-analyses found and reviewed, the first (Tulloch et al., 2018) is on older adults, the second (Knobben, 2013) is a non-peer reviewed master’s thesis, and the third (Hendriks et al., 2017) includes only two RCTs for the outcome of life satisfaction. Hendriks et al. (2017) also add: “the findings of this study must be interpreted with caution due to the clinical heterogeneity of the intervention in regard to the various yoga traditions and the differences in duration and frequency of the intervention. In addition to the heterogeneity, most studies displayed poor methodological reporting, making a clear risk of bias assessment practically impossible.”

A review of yoga as a mental health promoting tool (Domingues, 2018) also concludes: “the evidence for yoga effectiveness and efficacy is still in its infancy. In the arena of positive psychology, yoga studies are scarce, and results are inconsistent and lack statistical power, but most studies observe increasing trends in the promotion of positive mental health indicators due to yoga practice. Therefore, yoga interventions have been highly recommended in a variety of settings, as a complementary lifestyle practice. Nonetheless, more research is needed to properly understand the underlying mechanisms responsible for the positive results of yoga on physical and mental health.”

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 Weak evidence on the experiences with yoga of different groups is mentioned on this NIH page.

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 Hendriks et al. (2017): “Research indicates that the various yoga styles do not differ in their odds of reaching positive conclusions, so there will be no differentiation of the effects per style.”

Knobben (2013): “All the yoga forms share the same methods, which are breathing, physical exercise and mediation, but only the emphasizes differ. It’s unclear how much the three methods are used in proportion by each form of yoga. For this reason, the type of yoga will not be further analyzed as a moderator in this paper.”

Tulloch et al. (2018): “Due to the small number of studies included in this review, we were unable to complete a meta-regression analysis which makes it difficult to determine if there are differential effects of yoga on the outcome measures with higher doses of yoga and in different clinical populations. While this review provides evidence of the beneficial effect of physical yoga on HRQOL and mental well-being in people aged 60 years and over, further research is required to identify the optimal dose, type and frequency of yoga programme that maximises health outcomes.”

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 Cramer et al. (2016): “this review demonstrates that there is no evidence that trials on one yoga style are generally more likely to be positive than those on another style. Given that more than 90% of all RCTs of yoga were positive, the choice of an individual yoga style can be based on personal preferences and availability.”

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 Cramer et al. (2016): “The most commonly used yoga styles were hatha yoga (36 RCTs), Iyengar yoga (31 RCTs), and the integrated approach to yoga therapy (15 RCTs).”

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 We haven’t reviewed it but Mayo Clinic uses this book for their instructions on yoga poses.

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 Smyth (1998), introductory section.

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 Pennebaker and Chung (2007), section Why Does Expressive Writing Work?, reviews the different possible underlying mechanisms that can explain the effectiveness of expressive writing.

Sloan and Marx (2004) also presents three theoretical models seeking to explain the beneficial effects associated with expressive writing (emotion inhibition, cognitive adaptation, and exposure/ emotional processing), along with examining their empirical support.

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 We didn’t include the other meta-analyses on expressive writing (listed in Pennebaker (2017), section The Backstory of the Expressive Writing Research) because they didn’t evaluate wellbeing as an outcome or weren’t on the general population.

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 Agteren et al. (2021): “The evidence quality was low due to issues with risk of bias and the presence of a wide confidence interval.”

Sloan and Marx (2004): “as outlined in this paper, the empirical findings have been equivocal, and there is insufficient evidence to support the use of the writing paradigm as a therapeutic modality at this time. There seem to be some benefits that are derived from written emotional disclosure, although caution is warranted.”

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 Pennebaker and Chung (2007): “Whereas the original writing studies asked people to write about traumatic experiences, later studies expanded the scope of writing topics to general emotional events or to specific experiences shared by other participants (e.g., diagnosis of cancer, losing a job, coming to college).”

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 Smyth (1998): “Overall effect sizes [i.e. including the four outcomes of reported physical health, psychological well-being, physiological functioning, and general functioning] were moderated by two variables: Higher percentages of males in a study were related to higher mean effect sizes, as was longer periods over which writing sessions were spaced. Psychological well-being effect sizes were [positively] moderated by [...] instructions to write about current traumas (as opposed to past or current trauma).”

Pennebaker (1997): “In Smyth's (1996) meta-analysis, he found a promising trend suggesting that the more days over which the experiment lapses, the stronger the effects. Although this was a weak trend, it suggests that writing once each week over a month may be more effective than writing four times within a single week.”

See also Pennebaker and Chung (2007), section Procedural differences that affect the expressive writing, for a (probably now somewhat outdated) review of factors that can impact the intervention’s effectiveness, although not specifically for improving wellbeing.

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 Pennebaker and Chung (2007), section The basic writing paradigm.

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 The Writing Cure is another book that discusses techniques to practice the intervention, but aimed at researchers and clinical practitioners.

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 And you can find other self-help books on writing in the Reading list at the end of Expressive Writing: Words That Heal.

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 Akhtar and Barlow (2018), section Introduction.

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 Akhtar and Barlow (2018), section Introduction.

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 Gao et al. (2022).

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 Akhtar and Barlow (2018), section Introduction.

We also found the following definition in a meta-analysis by Lundahl et al. (2008): “forgiveness is defined as the willful giving up of resentment in the face of another’s (or others’) considerable injustice and responding with beneficence to the offender even though that offender has no right to the forgiver’s moral goodness”. (We didn’t include this meta-analysis in our review because of its insufficient quality. According to Akhtar and Barlow (2018): “[the meta-analysis by Lundahl et al., 2008 has] significant limitations [...] the authors [...] meta-analyzed data from both randomized controlled trials (RCTs) and non-RCTs, did not make direct comparisons with a no-treatment/wait-list control group, and used both validated and unvalidated scales”).

Lastly, this one-page document discusses what seems to be a reference definition of forgiveness: “When unjustly hurt by another, we forgive when we overcome the resentment toward the offender, not by denying our right to the resentment, but instead by trying to offer the wrongdoer compassion, benevolence, and love; as we give these, we as forgivers realize that the offender does not necessarily have a right to such gifts.”

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 Akhtar and Barlow (2018), section Forgiveness Interventions.

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 Akhtar and Barlow (2018), section Generalizability: “The studies [...] evaluated the effectiveness of forgiveness interventions, with people experiencing a range of problems such as sexual abuse, abortions, marital hurts, civil conflict, and a range of other hurtful interpersonal experiences, and the findings are therefore generalizable to a range of hurts or abuse.”

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 Worthington (2019), section DIY Workbooks and Internet-Delivered Online “Workbooks”: “most people have hurts and offenses that can be extremely troubling and last for decades while not being incapacitating enough to seek psychotherapy. For many others, hurts are relatively minor. Some people simply wish to practice forgiveness as challenges arise through life.”

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 Fincham et al. (2016).

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 Wade and Tittler (2019), section Self-guided interventions: “For people who might be unable or unwilling to attend a facilitated group or specific psychotherapy to promote forgiveness, a self-guided intervention might be warranted. Even simply reading a book on forgiveness might be somewhat helpful. This is a tentative conclusion however given the limited number of research studies on self-guided interventions and the small sample sizes of these studies. More work needs to be done to understand if and when a self-guided forgiveness intervention is more effective.”

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 Both Forgiveness is a choice and The Forgiving Life are in the selection of “APA Life Tools Series”, which apparently are supposed to be “the best psychology can offer.”

Forgiveness is a choice was tested in two RCTs, but not directly on wellbeing outcomes, with slightly encouraging results (Wade and Tittler, 2019, section Self-guided interventions).

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 This article briefly reviews the book and outlines the forgiveness process described in it.

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 The workbooks have been tested, but not directly on wellbeing outcomes: “In four of the studies, participants followed a workbook informed by Worthington’s (2006) REACH forgiveness treatment. In three of these studies, participants in the workbook treatment condition reported significantly greater improvement in forgiveness [...] than those in the waiting list condition.” (Wade and Tittler, 2019, section Self-guided interventions).

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 Pinquart and Forstmeier (2012), section Introduction.

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 Pinquart and Forstmeier (2012): “only about 6% of the available intervention studies focused on young and middle-aged adults, and some of them assessed individuals with severe physical illness [...] Thus, there is a need for more research on the effects of reminiscence interventions on young or middle-aged adults.”

Also, the only accessible descriptions of reminiscence activities usable for self-help we found were for older adults: this book for caregivers, this book in Dutch, and Ingersoll-Dayton and Bommarito (2006), p.783-785.

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 Hallford and Mellor (2013).

Among several arguments, they write: “The fact that treatment effects are not stronger for adults in the higher age range of these samples refutes the notion that reminiscence becomes a more relevant or effective therapeutic tool as adults enter, and progress through, late life. Recent meta-analytic findings also show that therapeutic effects on depression do not differ between older adults and young or middle-aged adults (Pinquart & Forstmeier, 2012), although notably there were very few studies available for this comparison.”

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 Hallford and Mellor (2015).

See their rationale for the approach and intervention: “Autobiographical memory [AM] serves a range of purposes essential to adaptive psychological functioning, including maintaining a coherent sense of self and self-continuity, social-bonding to improve interpersonal relationships, and self-directive purposes in problem-solving. In a clinical and counselling context, reminiscence-based therapy is one form of intervention that focuses on the retrieval of AMs, as well as reflection on their content.” and “The guided recalling and reviewing of [problem-solving and identity related] personal memories is thought to represent an adaptive process that can enhance self-concept and improve well-being, whilst also balancing or redressing dysfunctional or unhelpful views of the self.”

And they confirm that the intervention has a beneficial effect independently of the pleasantness of recalling positive memories: “As the reminiscence conditions did not differ on positively valenced outcomes and feelings relating to the AMs, the observed effects of problem-solving and identity reminiscence activities did not appear to be due simply to recalling positive memories. If the sole factor in change was that memories were evaluated in a positive way, then effects on measures in the control condition should have been observed. Instead, these findings suggest that reminiscence for problem-solving and identity purposes has an intrinsically adaptive role in improving self-concept and well-being.”

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 Wing et al. (2006), section Writing About Positive Events.

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 Wing et al. (2006).

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 Gander et al. (2016).

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 Miller and Duncan (2015).

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 GGSC is a social science research non-profit that supports research into wellbeing.

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 Another online media focused on happiness is Live Happy.

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 “APA LifeTools is a special imprint of American Psychological Association books written to help the general public find the best psychology can offer.”, according to this psychologist.

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