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feijão

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The studies I linked above started measuring 2-10 minutes after stunning, but there are other studies which have measured CNS activity before, during, and immediately after the stunning process - for example, Fregin & Bickmeyer (2016). Interestingly, they observed that before settling into a quiescent state, intense epileptic-form seizures occur in the CNS that last for up to an hour after stunning. In mammals, epileptic-form seizures are associated with a loss of consciousness and a lack of subjective experience during that period, suggesting insensibility (and this is roughly how the authors interpret their finding). However, more work needs to be done to better understand this phenomenon in decapod crustaceans.

I'm not focussing on the asphyxiation process, so I'll let someone with more knowledge in that area chime in. If no one does, I'd be happy to look into it!

If the central nervous system has truly stopped functioning, that would imply insensibility. That’s why loss of all measurable brain activity is taken as a sign of unconsciousness in clinical contexts. In humans, episodes with reduced CNS activity (for example, during deep anaesthesia or certain brain injuries) are generally associated with a lack of subjective experience.

For decapods, the challenge is that most studies measure spontaneous CNS activity rather than testing every possible form of responsiveness, such as testing to see whether we can evoke CNS responses through stimulation. So while prolonged inactivity is a strong sign of insensibility, researchers should still gather more data to increase confidence (especially given that, as you mention, we are putting a lot of resources behind this!)

Answer by feijão51
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I’m actually in the middle of a literature review on this exact topic - electrical stunning in decapod crustaceans. There’s reasonable evidence from several species (e.g., Carcinus maenas (crabs), Homarus gammarus (lobsters), Nephrops norvegicus (lobsters), Paranephrops zealandicus (crayfish)) that correctly applied electrical stunning can abolish neural activity for several hours, which is generally taken to indicate insensibility (Neil et al., 2024; Neil et al., 2022; Albalat et al., 2022). 

There are no published studies directly measuring neural responsiveness in shrimp after stunning. However, post-stun behavioural quiescence in shrimp looks very similar to the behaviours seen in those other species where neural shutdown has been demonstrated. This is why it’s generally inferred that the method would work for shrimp as well, though experimental validation is still needed and mapping out how to achieve that will be one of the aims of my review.

These are all really important questions, and its great that you want to engage in discussion about it!

Have you looked at the Moral Weight Project? It's a great piece of work that tries to tackle the (very complex, as you state) issue of comparing the welfare of different species, including humans. All their assumptions are explicitly listed, so you can look through and see where you disagree. There is a great sequence about it on the forum here: https://forum.effectivealtruism.org/s/y5n47MfgrKvTLE3pw

And I also wrote a couple of more accessible explainers of the project here:

https://docs.google.com/document/d/16EdSGP1-xs0Mh4G6QfQYOaaYfduDEpp32NK5BBlznYE/edit?tab=t.0

https://docs.google.com/document/d/1SIurNLZB8hSXTCKUNmREHmBt2sP4IQ4R0XkdYAZbYp0/edit?tab=t.0

Answer by feijão2
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I just wanted to say that this is awesome and very impressive. How long did it take you? I agree that this seems like an excellent way of interactively learning about these biases and how they operate, compared to just reading about them.

I know this is an old post, but I thought I’d comment anyway. When I talk to people about EA, even when I try to do so in an open, constructive, and non-judgemental way, I often get that "tautological egoism" response. People tell me it’s just as selfish to try to improve the world for everyone as it is to focus only on your own life, as we're all just doing what we want.

Maybe I’m biased, but it really does feel like a case of motivated reasoning and a way to avoid the discomfort of cognitive dissonance.

Are you aware of any good, accessible explainers that respond to this "everyone is just as selfish" idea? I’ve seen more technical arguments showing how psychological egoism collapses into a tautology, but I’m looking for something easier to read and more accessible. Thanks!

Given that I'm naturally more into the communication rather than generation of research/ideas, this quick take especially resonates with me. But your comment has encouraged me to post in the near future - putting things in one place and communicating them well can be useful!

 

Thanks for the encouragement! I hadn't heard of Tlön before, but now I've sent them an email - thank you!