(Maybe this comment would be more appropriate on another one of the posts of the series, perhaps this one or this one, but I’ve decided to leave it here since this is the most recent post about sentience across species. This is mostly speculative and suggestive of areas for further research and questions that could inform our credences in consciousness.)
I haven’t been able to find the paper, unfortunately, but I thought this might be pretty good evidence for consciousness:
Another way to tap into an animal’s emotions is to train them to communicate how they feel. A group of researchers from London taught pigs to give one response when they felt normal and a different response when they were anxious (in this case they were given a drug designed to induce temporary anxiety). Not only could the pigs discriminate between these two states, but later they made the same “anxious” response when exposed to novel events such as an unfamiliar pig or a new pig pen. It seems that, since pigs are smart enough to tell researchers how they feel, they could be trained to understand that although a routine husbandry procedure might be frightening, it could be over relatively quickly and painlessly.
If an animal can discriminate between their own emotions and be taught to react to them in different ways (and not just to external stimuli or representations thereof), is this a sign of some kind of higher-order consciousness? Their learning systems are taking their own emotions as input to learn about, rather than just as final signals (e.g. reinforcers) for learning, and their emotions are being passed through their learning systems and not just directly to changes outside their brains (tail wagging, growling, stress hormones in the blood, etc.).
Together (although I’m generalizing between species), this may suggest these animals can:
1. learn about their own emotional reactions, and
2. react emotionally to their own learning.
I suppose learning does not imply “knowing” or “thinking”, though, which should involve consciousness. So the pigs and dog seem to be able to learn about their emotions, but do they “know” or “think about” their emotions? The cows seem to react to their own learning/progress, but do they “know” that they’re learning/making progress?
On the other hand, how far is this kind of behaviour from nonhuman primates being able to communicate using sign language and how good was that as evidence for nonhuman primate consciousness? Nonhuman primates may have learned to communicate more than just their emotions, including perhaps past events (skepticism here, though), which would be evidence for episodic memory.
But maybe even rats have episodic memory and perform mental time.[1][2] It seems worth investigating whether or not these memory replays are associated with emotions similar to the original events; if that’s the case, that would be a good sign that they’re actually experiencing the “simulation”. I’d imagine that when a dog runs in their sleep, they’re simulating experiences and actually experiencing the simulation, emotions and all, although the claim that dreams are actually experienced while they’re happening in humans if not lucid—rather than just at recall after waking up—is debated in philosophy. Some related reading: [3][4][5]
It also seems worth looking into intentionality here: do they ever consider alternatives (e.g. run multiple simulations) and then make a decision based on the outcomes of the simulations? Can they choose to recall or run simulations in the first place?
An excerpt on gorilla sign language for emotions and memories from this paper (bold mine):
Which nonhuman animals may be near-persons like Jenny? Reviewing the evidence, Varner argues that the category includes great apes, cetaceans, elephants, and, perhaps, corvids and parrots. To defend his claim that great apes do not have the kind of episodic memory required to have a biographical sense of one’s past, he examines the evidence provided for believing that Koko, the gorilla, has narrative and uses it to communicate deeply emotional personal memories from the distant past.
Koko was five years old in July, 1976. According to Francine “Penny” Patterson, who worked more closely with Koko than anyone, in 1976 Koko narrated an event that had happened three days prior:
(P = Patterson; K = Koko)
P: What did you do to Penny?
K: BITE.
P: You admit it? (Koko had earlier called the bite a SCRATCH.)
K: SORRY BITE SCRATCH. (Penny shows the mark on her hand; it does resemble a scratch.)
K: WRONG BITE.
P: Why bite?
K: BECAUSE MAD.
P: Why mad?
K: DON’T KNOW
(Patterson & Cohn, 1994, p.282)
Koko’s one and two word responses here, drawn from her knowledge of more than a thousand American Sign Language (ASL) signs, clearly show an understanding of concepts, words, and causal relations (What did you do to Penny? BITE). However, as Varner notes, there is no evidence here of episodic memory, in which one remembers oneself at a particular place at a particular time. Koko is using ASL which, Varner tells us, does not include tenses. Consequently, he observes, “temporal references must generally be inferred from the context, and in these studies, that context is provided by the English sentences uttered by the human trainers” (Varner, 2012, p.155). Varner has his doubts about whether Koko is here communicating a conscious memory of what happened three days ago. Rather, Koko may simply be making signs she knows will succeed in eliciting the responses Koko desires from Patterson.
But if Koko is not capable of expressing memories of events three days in the past, she is able to communicate her emotions. When asked, “How do you feel?” she will respond appropriately, for example, with FINE, or HUNGRY, or SAD. In children, internal immediate-state language reporting one’s mood emerges in the third and fourth years. We are on firm ground, then, in thinking Koko has words and concepts, social communication, rationality in the sense of cause and effect thinking, emotions, awareness, and beliefs and desires. But she does not seem to have the second-order desires, executive control, or autonomy required for a biographical sense of self.
Varner is similarly cautious about long-term memories allegedly recounted by a gorilla, Michael, who was captured by poachers as an infant. Patterson made a video of Michael allegedly recounting this memory of the incident in which Michael’s mother was killed. In the recording we see Michael’s signings rendered in the following captions provided by Patterson: “SQUASH MEAT GORILLA. MOUTH TOOTH. CRY SHARP-NOISE LOUD. BAD THINK-TROUBLE LOCK-FACE. CUT/NECK LIP(GIRL) HOLD” (The Gorilla Foundation, n.d.). Varner, noting the ambiguity of the string of words, observes that “even Patterson’s sympathetic co-author Eugene Linden doubts her claim that Michael was telling the story about his mother’s death” (Ibid, pp.155–156). Varner concludes that in spite of such anecdotes and Patterson’s claim that Michael told her this story on several occasions, there is “no good evidence that apes understand or use language to express thoughts about the non-immediate past” (Ibid, pp.156). If Varner is wrong and Michael is recounting an episodic memory, Michael has an important claim to personhood. If Varner is right, perhaps Michael is just making signs he thinks Patterson is subconsciously nudging him to make, perhaps in Clever Hans fashion. In that event, Michael may not have episodic memories of the traumatic events. Rather, he may only be signing in sequences he has learned satisfy Patterson’s promptings.
Also, for another comparison, children only really start passing the mirror test at around 2 years old.
EDIT: On further consideration, “In children, internal immediate-state language reporting one’s mood emerges in the third and fourth years” seems suspiciously late to me.
Also interesting here to reflect on what it’d mean for consciousness & intentionality to be (mostly) orthogonal, though that heads down a different road.
Thanks for the interesting comment and many useful references. Speaking for myself and not for the rest of the team, I am very confident that dogs, pigs, cows, rats, and apes are all sentient and have the capacity for valenced experience. (That is, there is something it is like to be these animals and that experience includes pleasures and pains.) Whether or not these creatures are capable of higher-order conscious thought (that is, reflecting on their own first-order beliefs, desires, or emotional states) is debatable. I don’t think higher-order conscious thought is a necessary condition for sentience, but I do think it may be relevant to moral status. In fact, many of the features mentioned in your comment (e.g., episodic memory, emotional complexity and awareness, social communication, cause-and-effect thinking, executive control, autonomy, biographical sense of self) plausibly help determine a creature’s moral status. (Even if you are suspicious of degrees of moral status, you might think that these features contribute to the range and types of experiential states a creature can undergo and thus are important for determining a creature’s welfare.) So I think it would be good for the animal welfare movement to have a decent grasp of which of these features (as well as the other features that plausibly affect moral status) are exhibited by which animals. In the coming months, Rethink Priorities might have something more concrete to say about the topic.
I do agree that higher-order consciousness is unlikely to be necessary for sentience, but some disagree (not any of the authors here, AFAIK), and showing them that there’s a good chance many animals are capable of higher-order consciousness could lead to further consideration for these animals’ interests. Unfortunately, this may neglect many animals whom we think aren’t capable of higher-order consciousness or even entrench the view that higher-order consciousness is necessary.
Also, pigeons and rats seem to be able to answer unexpected questions about what they’ve just done. See the section “The unexpected question” here. This is, of course, different from reporting an internal state, though.
(Maybe this comment would be more appropriate on another one of the posts of the series, perhaps this one or this one, but I’ve decided to leave it here since this is the most recent post about sentience across species. This is mostly speculative and suggestive of areas for further research and questions that could inform our credences in consciousness.)
I haven’t been able to find the paper, unfortunately, but I thought this might be pretty good evidence for consciousness:
If an animal can discriminate between their own emotions and be taught to react to them in different ways (and not just to external stimuli or representations thereof), is this a sign of some kind of higher-order consciousness? Their learning systems are taking their own emotions as input to learn about, rather than just as final signals (e.g. reinforcers) for learning, and their emotions are being passed through their learning systems and not just directly to changes outside their brains (tail wagging, growling, stress hormones in the blood, etc.).
More recently, there’s the dog who was trained to press buttons that play words. At about 4:00, after a button didn’t work, the dog pressed “No” and “Help”.
And then cows may be able to react emotionally to their own learning, specifically, to their progress on a problem. Maybe this kind of learning is distinct from the kind of learning pigs and dogs seem to do about their own emotions.
Together (although I’m generalizing between species), this may suggest these animals can:
1. learn about their own emotional reactions, and
2. react emotionally to their own learning.
I suppose learning does not imply “knowing” or “thinking”, though, which should involve consciousness. So the pigs and dog seem to be able to learn about their emotions, but do they “know” or “think about” their emotions? The cows seem to react to their own learning/progress, but do they “know” that they’re learning/making progress?
On the other hand, how far is this kind of behaviour from nonhuman primates being able to communicate using sign language and how good was that as evidence for nonhuman primate consciousness? Nonhuman primates may have learned to communicate more than just their emotions, including perhaps past events (skepticism here, though), which would be evidence for episodic memory.
But maybe even rats have episodic memory and perform mental time.[1][2] It seems worth investigating whether or not these memory replays are associated with emotions similar to the original events; if that’s the case, that would be a good sign that they’re actually experiencing the “simulation”. I’d imagine that when a dog runs in their sleep, they’re simulating experiences and actually experiencing the simulation, emotions and all, although the claim that dreams are actually experienced while they’re happening in humans if not lucid—rather than just at recall after waking up—is debated in philosophy. Some related reading: [3][4][5]
It also seems worth looking into intentionality here: do they ever consider alternatives (e.g. run multiple simulations) and then make a decision based on the outcomes of the simulations? Can they choose to recall or run simulations in the first place?
An excerpt on gorilla sign language for emotions and memories from this paper (bold mine):
Also, for another comparison, children only really start passing the mirror test at around 2 years old.
EDIT: On further consideration, “In children, internal immediate-state language reporting one’s mood emerges in the third and fourth years” seems suspiciously late to me.
Also interesting here to reflect on what it’d mean for consciousness & intentionality to be (mostly) orthogonal, though that heads down a different road.
Hi Michael,
Thanks for the interesting comment and many useful references. Speaking for myself and not for the rest of the team, I am very confident that dogs, pigs, cows, rats, and apes are all sentient and have the capacity for valenced experience. (That is, there is something it is like to be these animals and that experience includes pleasures and pains.) Whether or not these creatures are capable of higher-order conscious thought (that is, reflecting on their own first-order beliefs, desires, or emotional states) is debatable. I don’t think higher-order conscious thought is a necessary condition for sentience, but I do think it may be relevant to moral status. In fact, many of the features mentioned in your comment (e.g., episodic memory, emotional complexity and awareness, social communication, cause-and-effect thinking, executive control, autonomy, biographical sense of self) plausibly help determine a creature’s moral status. (Even if you are suspicious of degrees of moral status, you might think that these features contribute to the range and types of experiential states a creature can undergo and thus are important for determining a creature’s welfare.) So I think it would be good for the animal welfare movement to have a decent grasp of which of these features (as well as the other features that plausibly affect moral status) are exhibited by which animals. In the coming months, Rethink Priorities might have something more concrete to say about the topic.
Agreed!
I do agree that higher-order consciousness is unlikely to be necessary for sentience, but some disagree (not any of the authors here, AFAIK), and showing them that there’s a good chance many animals are capable of higher-order consciousness could lead to further consideration for these animals’ interests. Unfortunately, this may neglect many animals whom we think aren’t capable of higher-order consciousness or even entrench the view that higher-order consciousness is necessary.
Also, apparently the theories of higher-order consciousness are pretty broad (pdf, see especially table 1 there). Maybe most animals we suspect are conscious in the RP report would meet at least one definition of HOT.
Also, pigeons and rats seem to be able to answer unexpected questions about what they’ve just done. See the section “The unexpected question” here. This is, of course, different from reporting an internal state, though.