Based on everything youāve looked into, what odds do you put on fish sentience?
I speculate carp have around 50 % (= (0.70 + 0.40)/ā2) chance of being sentient, but I have little reason to expect my intuitions are calibrated. I feel like anything from 0.1 % to 90 % is reasonable. In any case, I can see the welfare of fish being very close to 0 even if they are sentient. So I would rather prioritise decreasing uncertainty about their sentience and intensity of their experiences over investing in interventions helping fish.
Here is some additional context you may be interested in about the likelihood of fish being sentient. Bob Fischerās book about comparing welfare across species presents an estimate of 70 % for the sentience of carp. Among the people surveyed in Zipple et al. (2024), as illustrated in Figure 1 below, around 40 % guessed āmostā or āall or nearly allā fish are conscious. Importantly, āwe defined consciousness for respondents, using a āself-consciousnessā or āself-awarenessā definition (an animal being aware of its own existence [33ā35])ā.
I would add, Iām not convinced that all āunconsciousā states in humans are equal. Iāve heard reports of people who āwake upā during surgery, but were still unable to move.
Anesthesia awareness is a real (though rare) phenomenon. However, note that people who are awake would no longer qualify as unconscious under the definition of the article.
I appreciate this paragraph, especially the extreme uncertainty and the welfare of fish being potentially close to zero even if sentient.
āI speculate carp have around 50 % (= (0.70 + 0.40)/ā2) chance of being sentient, but I have little reason to expect my intuitions are calibrated. I feel like anything from 0.1 % to 90 % is reasonable. In any case, I can see the welfare of fish being very close to 0 even if they are sentient. So I would rather prioritise decreasing uncertainty about their sentience and intensity of their experiences over investing in interventions helping fish.ā
What kind of research do you think could decrease uncertainty about their sentience? Iām assuming you mean behavioural research? I think this kind of research is helpful to reduce uncertainty but doesnāt necessarily address fundamental questions about how brains work.
What kind of research do you think could decrease uncertainty about their sentience?
The kind of research described in this section of the article. Tasks involving working memory, aspects of operant conditioning, self-report of sensation, or higher order consciousness (like the āmirror test with biting parasiteā, which offers stronger evidence for sentience than the standard mirror test). Below is some context from the article about why these tasks are promising. I bolded the 4 types of tasks.
here we suggest four types of candidate measure that seem particularly promising as indicators of sentience. One concerns working memory, and another, forms of operant conditioning: two types of ability that S.P.U.D. subjects seem not to convincingly have. A third type of candidate measure concerns self report. As we saw in the section Red Herrings: Responses That Do Not Require Sentience, unaware humans, and also monkeys with blindsight, report sensing nothing (thence having no P-consciousness), even when presented with stimuli that elicit other kinds of response ā with the human subjects consistently describing themselves as merely guessing. Finally, higher order cognitive processes such as episodic memory and self-recognition, can yield insights into animal awareness. These have not been studied in S.P.U.D. subjects, and this would likely be impossible, but are arguably reliant on perceptual consciousness. We review each of these below, and also outline how they could be modified to now address questions about sentience: the ethically relevant dimension of P-consciousness at the heart of the fish pain debate. We also suggest how their validity as indicators of sentience could be assessed.
In addition, tasks involving endogenous/āvoluntary attention, like Posnerās spatial cueing task, as discussed in Nieder (2022).
Iām assuming you mean behavioural research?
All of the above tasks look into behaviour. However, passing them would be stronger evidence for sentience than passing tasks that have been passed by SPUDs (spines disconnected from brains, humans in unaware states, decerebrate mammals and birds, or organisms lacking a nervous system like plants and protozoa).
I think this kind of research is helpful to reduce uncertainty but doesnāt necessarily address fundamental questions about how brains work.
Note that research looking for the neural correlates of consciosness (NCCs) in animals relies on studying the behaviour of humans. In particular, to understand which states of the human brain are responsible for consciousness. Nieder (2022) says there is no evidence for the neural correlates of consciousness in animals besides mammals and birds.
My apologies @Vasco Grilošø I was lazy there and didnāt read the whole article properly. Thanks for pointing out the important areas. Working memory and operant conditioning donāt carry any weight with me personally, I struggle to connect those with a meaningfully increased chance of pain experience. For example the portia spider has a very advanced working memory for very specific tasks which makes sense evolutionary, as do many other organisms, but i canāt imagine why these specific evolutionary advantages would also lead to sentience?
āFinally, higher order cognitive processes such as episodic memory and self-recognition, can yield insights into animal awareness. These have not been studied in S.P.U.D. subjects, and this would likely be impossibleā
These higher order processes would be most convincing for me than the memory stuff, especially deeper levels of self recognition which I feel like could maybe be tested?
Perhaps a silly question, but I thought the mirror/āparasite mirror test was related to āself recognitionā, but you seem to mention that as something different.
My apologies @Vasco Grilošø I was lazy there and didnāt read the whole article properly. Thanks for pointing out the important areas.
No worries. I could have highlighted them more too. So thanks for asking. I linked to the relevant section in this comment, but I have now linked to it at the top of the post too. āThe article has a section discussing promising ways of assessing sentience (here is some brief context [my comment just above])ā.
Nitpick. I get email notifications of comments on my posts, and replies to my comments even if I am not tagged. I think this is the default setting on the EA Forum. If I am tagged in those cases, I get 2 email notifications, although this does not bother me.
Working memory and operant conditioning donāt carry any weight with me personally, I struggle to connect those with a meaningfully increased chance of pain experience.
I would also give them the least weight among the 4 indicators, but I am not confident they should have negligible weight. I think negligible weight makes more sense for classical/ārespondant conditioning, as SPUDs are capable of this.
In addition, I believe some types of working memory and operant conditioning should have more weight than others. Here is some brief context from the post.
More stringently, it could be that not all operant learning requires sentience [it demonstrably does not require consciousness of the rewards and punishments], but that only some sub-types do. Thus, it could be that Ginsburg and Jablonkaās (37) hypothesis about second-order conditioning [context] is correct: again something not yet known, but amenable to empirical test. If their hypothesis is supported [it may not be], then again there are already some cases demonstrating conditioned responses to secondary reinforcers by fish.
These higher order processes would be most convincing for me than the memory stuff, especially deeper levels of self recognition which I feel like could maybe be tested?
Perhaps a silly question, but I thought the mirror/āparasite mirror test was related to āself recognitionā, but you seem to mention that as something different.
Both the mirror test and āmirror test with biting parasiteā test self-recognition, but the latter offers stronger evidence for sentience. I asked Gemini 3.5 Flash to contrast the 2 tests with respect to this given the articleās description of the āmirror test with biting parasiteā. The answer is below. I think it is good, except that it is overconfident (as it is often the case with LLMs). Words like āprovesā and ādemonstratesā should be replaced with āoffers stronger evidence (relative to the standard mirror test) forā.
The standard mirror test is widely used to check for self-awareness, but it doesnāt tell us if an animal can actually feel things like pleasure or pain.
Mason and Lavery (2022) proposed a modified version to bridge this gap. Here is how the two tasks contrast and why the new one offers stronger evidence for sentience.
The Two Tasks Contrasted
The Standard Mirror Test (Affectively Neutral): An animal is marked with a spot (like a dot of odorless, painless paint) in a place it can only see using a mirror (like its forehead). If the animal looks in the mirror and then grooms, touches, or scrapes its own body where the mark is, it passes. This proves the animal understands that the reflection is āmeā rather than another animal, showing a baseline of physical and visual self-awareness. However, because the mark doesnāt feel like anything, the task is affectively neutralāit doesnāt involve emotions or feelings.
The āMirror Test with a Biting Parasiteā (Affectively Charged): This version introduces feelings. Instead of a neutral dot, the animal is trained to associate different visual marks with physical comfort or discomfort. For example:
The animal is exposed to a black triangle mark that is physically uncomfortable or painful (simulating a biting parasite).
It is also exposed to a white circle mark that causes no discomfort at all.
Finally, the researchers place these marks on the animalās body without any actual pain or discomfort attached, in a spot the animal can see directly or via a mirror. The test checks if the animal reacts with greater urgency, anxiety, or scraping behaviors toward the ānastyā black triangle than the ābenignā white circle, purely based on what it looks like.
Why the Parasite Test Provides Stronger Evidence for Sentience
To understand why the parasite version is stronger, it helps to separate two concepts: awareness and sentience.
Passing the standard mirror test proves awarenessāspecifically, the cognitive ability to map visual reflections to oneās own physical body. But critics argue that a highly complex, non-sentient robot or AI could theoretically pass this test using pure geometry and visual processing, without experiencing any inner feelings.
The biting parasite test targets phenomenal consciousness (P-consciousness) and affective statesāthe actual capacity to subjectively feel pain, fear, or distress.
By showing that an animal doesnāt just recognize a mark, but specifically anticipates and reacts to the remembered emotional and painful quality of that mark, the test demonstrates that the animal experiences the world through a lens of āgoodā and ābadā feelings. It links visual self-recognition directly to an inner emotional state (the desire to avoid pain), providing much sturdier proof that the animal is truly sentient and capable of suffering.
Hello.
I speculate carp have around 50 % (= (0.70 + 0.40)/ā2) chance of being sentient, but I have little reason to expect my intuitions are calibrated. I feel like anything from 0.1 % to 90 % is reasonable. In any case, I can see the welfare of fish being very close to 0 even if they are sentient. So I would rather prioritise decreasing uncertainty about their sentience and intensity of their experiences over investing in interventions helping fish.
Here is some additional context you may be interested in about the likelihood of fish being sentient. Bob Fischerās book about comparing welfare across species presents an estimate of 70 % for the sentience of carp. Among the people surveyed in Zipple et al. (2024), as illustrated in Figure 1 below, around 40 % guessed āmostā or āall or nearly allā fish are conscious. Importantly, āwe defined consciousness for respondents, using a āself-consciousnessā or āself-awarenessā definition (an animal being aware of its own existence [33ā35])ā.
Anesthesia awareness is a real (though rare) phenomenon. However, note that people who are awake would no longer qualify as unconscious under the definition of the article.
I appreciate this paragraph, especially the extreme uncertainty and the welfare of fish being potentially close to zero even if sentient.
āI speculate carp have around 50 % (= (0.70 + 0.40)/ā2) chance of being sentient, but I have little reason to expect my intuitions are calibrated. I feel like anything from 0.1 % to 90 % is reasonable. In any case, I can see the welfare of fish being very close to 0 even if they are sentient. So I would rather prioritise decreasing uncertainty about their sentience and intensity of their experiences over investing in interventions helping fish.ā
What kind of research do you think could decrease uncertainty about their sentience? Iām assuming you mean behavioural research? I think this kind of research is helpful to reduce uncertainty but doesnāt necessarily address fundamental questions about how brains work.
Hi Nick.
The kind of research described in this section of the article. Tasks involving working memory, aspects of operant conditioning, self-report of sensation, or higher order consciousness (like the āmirror test with biting parasiteā, which offers stronger evidence for sentience than the standard mirror test). Below is some context from the article about why these tasks are promising. I bolded the 4 types of tasks.
In addition, tasks involving endogenous/āvoluntary attention, like Posnerās spatial cueing task, as discussed in Nieder (2022).
All of the above tasks look into behaviour. However, passing them would be stronger evidence for sentience than passing tasks that have been passed by SPUDs (spines disconnected from brains, humans in unaware states, decerebrate mammals and birds, or organisms lacking a nervous system like plants and protozoa).
Note that research looking for the neural correlates of consciosness (NCCs) in animals relies on studying the behaviour of humans. In particular, to understand which states of the human brain are responsible for consciousness. Nieder (2022) says there is no evidence for the neural correlates of consciousness in animals besides mammals and birds.
My apologies @Vasco Grilošø I was lazy there and didnāt read the whole article properly. Thanks for pointing out the important areas. Working memory and operant conditioning donāt carry any weight with me personally, I struggle to connect those with a meaningfully increased chance of pain experience. For example the portia spider has a very advanced working memory for very specific tasks which makes sense evolutionary, as do many other organisms, but i canāt imagine why these specific evolutionary advantages would also lead to sentience?
āFinally, higher order cognitive processes such as episodic memory and self-recognition, can yield insights into animal awareness. These have not been studied in S.P.U.D. subjects, and this would likely be impossibleā
These higher order processes would be most convincing for me than the memory stuff, especially deeper levels of self recognition which I feel like could maybe be tested?
Perhaps a silly question, but I thought the mirror/āparasite mirror test was related to āself recognitionā, but you seem to mention that as something different.
No worries. I could have highlighted them more too. So thanks for asking. I linked to the relevant section in this comment, but I have now linked to it at the top of the post too. āThe article has a section discussing promising ways of assessing sentience (here is some brief context [my comment just above])ā.
Nitpick. I get email notifications of comments on my posts, and replies to my comments even if I am not tagged. I think this is the default setting on the EA Forum. If I am tagged in those cases, I get 2 email notifications, although this does not bother me.
I would also give them the least weight among the 4 indicators, but I am not confident they should have negligible weight. I think negligible weight makes more sense for classical/ārespondant conditioning, as SPUDs are capable of this.
In addition, I believe some types of working memory and operant conditioning should have more weight than others. Here is some brief context from the post.
Both the mirror test and āmirror test with biting parasiteā test self-recognition, but the latter offers stronger evidence for sentience. I asked Gemini 3.5 Flash to contrast the 2 tests with respect to this given the articleās description of the āmirror test with biting parasiteā. The answer is below. I think it is good, except that it is overconfident (as it is often the case with LLMs). Words like āprovesā and ādemonstratesā should be replaced with āoffers stronger evidence (relative to the standard mirror test) forā.