I do think blindsight is pretty compelling evidence for conscious visual sensation in species with regular sight and blindsight, as well as important evidence against conscious visual sensation in fish, frogs and reptiles, but I’m not sure what to make of it overall.
In mammals, there are two main pathways from the eye to the brain: an evolutionarily ancient one – the descendant of the visual system used by fish, frogs and reptiles – that goes to the optic tectum in the mid-brain, and a newer one that goes up to the cortex. In Helen, the older visual system was still intact. If a frog can see using the optic tectum, why not Helen?
So, fish, frogs and reptiles rely on a visual system that exists in humans (and other mammals and birds) that is not enough to generate conscious visual sensation in humans. The primary visual cortex seems necessary for conscious visual perception in mammals, and birds seem to have a functional analogue. (Are there studies of blindsight in birds?) On the other hand, fish, frogs and reptiles seem not to have any analogue. So, whatever functions or processes are necessary for conscious visual sensation in humans (and other mammals and birds) don’t seem to be realized in fish, frogs and reptiles.
However, I can imagine some possibilities that could undermine this argument:
The ancient system could have functions in fish, frogs and reptiles that the primary visual cortex in mammals has taken on, in a kind of evolutionary migration of some functions.
Whatever happens in the ancient system is not available in the “global workspace” in humans and so doesn’t result in conscious visual sensation, but it could be in fish, frogs and/or reptiles. It might be that the primary visual cortex and the cortex in general added extra layers before the global workspace and executive function, and there was no need for the ancient system to keep feeding directly into the global workspace in mammals and birds. So those connections were lost or replaced with connections that run through the primary visual cortex, which are lost or inactive in blindsight.
On the other hand, maybe fish, frogs and reptiles don’t have any global workspace at all, either. Nieder, 2022 writes “In contrast, reptiles and amphibians show no sign of either working memory or volitional attention. Surprisingly, some species of teleost fishes exhibit elementary working memory and voluntary attention effects suggestive of possibly rudimentary forms of subjective experience. With the potential exception of honeybees, evidence for conscious processing is lacking in invertebrates.” That being said, I don’t think he cites any negative results, so this is not evidence of absence, just absence of evidence. And the fact that some fish seem to have working memory and voluntary attention suggests those fish do have something like a global workspace, despite no cortex and these functions being realized in the human cortex.
Blindsighted humans do have conscious visual sensation, just not accessible for report.
Also related is Mason, G., & J. Michelle Lavery. (2022). What Is It Like to Be a Bass? Red Herrings, Fish Pain and the Study of Animal Sentience. Frontiers in Veterinary Science, 9. https://doi.org/10.3389/fvets.2022.788289
From the abstract:
After reviewing key consciousness concepts, we identify “red herring” measures that should not be used to infer sentience because also present in non-sentient organisms, notably those lacking nervous systems, like plants and protozoa (P); spines disconnected from brains (S); decerebrate mammals and birds (D); and humans in unaware states (U). These “S.P.U.D. subjects” can show approach/withdrawal; react with apparent emotion; change their reactivity with food deprivation or analgesia; discriminate between stimuli; display Pavlovian learning, including some forms of trace conditioning; and even learn simple instrumental responses. Consequently, none of these responses are good indicators of sentience. Potentially more valid are aspects of working memory, operant conditioning, the self-report of state, and forms of higher order cognition. We suggest new experiments on humans to test these hypotheses, as well as modifications to tests for “mental time travel” and self-awareness (e.g., mirror self-recognition) that could allow these to now probe sentience (since currently they reflect perceptual rather than evaluative, affective aspects of consciousness). Because “bullet-proof” neurological and behavioral indicators of sentience are thus still lacking, agnosticism about fish sentience remains widespread.
Humphrey’s argument fish aren’t conscious doesn’t only rest on their not having the requisite brain structures, because as you say, it is possible consciousness could have developed in their own structures in ways that are simply distinct from our own. But then, Humphrey would ask, if they have visual sensations, why are they uninterested in play? When you have sensations, play can teach you a lot about your own sensory processes and subsequently use what you’ve learned to leverage your visual sensations to accomplish objectives. It seems odd that an organism that can learn (as almost all can) would evolve visual sensations but not a propensity to play in a way that helps them to learn about those sensations.
Perhaps fish just don’t benefit from learning more about their visual sensations. The sensations are adaptive, but learning about them confers no additional adaptive advantage. That seems a stretch to me, because it’s hard for me to imagine sensations being adaptive without learning and experimenting with them conferring additional advantage.
You could also respond by citing examples where fish can play, and are motivated to sensation-seek, as you already have, and I think if Humphrey believes your examples he would find that persuasive evidence about those organisms consciousness.
Does he spell out more why it’s useful to learn more about your own sensations? Also, couldn’t this apply to any perception that feeds into executive functions/cognitive control, conscious or not?
What if sensory play is just very species-specific? Do the juveniles of every mammal and bird species play? Would he think the species without play aren’t conscious, even if they have basically the same sensory neural structures?
A motivation to engage in (sensory) play has resource costs. Playing uses energy and time, and it takes energy to build the structures responsible for the motivation to play. And the motivation could be risky without a safe environment, e.g. away from predators or protection by parents and with enough food. Fish larvae don’t seem to get such safe environments.
I guess a thesis he’s stated elsewhere is that it’s the function of consciousness to matter. This is the adaptive belief it causes. So, conscious sensations should just be interesting to animals with them, and maybe without that interest, there’s no benefit to conscious sensation. This doesn’t seem crazy to me, and it seems pretty plausible with my sympathies to illusionism. Consciousness illusions should be adaptive in some way.
But, this only tells me about conscious sensation. Animals without conscious sensation could still have conscious pleasure, unpleasantness and desires, which realize the mattering and interest. And animals don’t engage in play to explore unpleasantness and aversive desire. So what are the benefits of unpleasantness and aversive desire being conscious as opposed to unconscious? And could there be similar benefits for conscious sensation? If there are, then sensory play may not be (evolutionarily) necessary for consciousness in general or conscious sensation in particular after all.
To me “conscious pleasure” without conscious sensation almost sounds like “the sound of one hand clapping”. Can you have pure joy unconnected to a particular sensation? Maybe, but I’m sceptical. First, the closest I can imagine is calm joyful moments during meditation, or drug-induced euphoria, but in both cases I think it’s at least plausible there are associated sensations. Second, to me, even the purest moments of simple joy seem to be sensations in themselves, and I don’t know if there’s any conscious experience without sensations.
Humphrey theorises that the evolutionary impulse for conscious sensations includes (1) the development of a sense of self (2) which in turn allows for a sense of other, and theory of mind. He thinks that mere unconscious perception can’t be reasoned about or used to model others because, being unconscious, it is inaccessible by the global workspace for that kind of use. in contrast, conscious sensations are accessible in the global workspace and can be used to imagine the past, future, or what others are experiencing. The cognitive and sensory empathy that allows can enable an organism to behave socially, to engage in deceit or control, to more effectively care for another, to anticipate what a predator can and can’t see, etc.
I would add that conscious sensation allows for more abstract processing of sensations, which enables tool use and other complex planning like long term planning in order to get the future self more pleasurable sensations. Humphrey doesn’t talk about that much, perhaps because it’s only a small subset of conscious species that have been observed doing those things, so perhaps mere consciousness isn’t sufficient to engage in them (some would argue you need language to do good long term planning and complex abstraction).
Humphrey believes that mammals in general do engage in play, which he thinks all (but not only) conscious animals do, and that they also engage in sensation-seeking (e.g. sliding down slopes or moving fast through the air for no reason), which he thinks only (but not all) conscious animals do. And he’d say the same thing about birds, and the fact that those behaviors’ distribution over species lines up nicely with the species with neural structures he thinks generates consciousness he treats as additional confirmation of his theory.
Animals do engage in play with unpleasant experiences, e.g., playfighting can include moderately unpleasant sensations. I suppose the benefits of those experiences being conscious might be to form more sophisticated strategies of avoiding them in future. It isn’t that Humphrey thinks play is necessary for conscious to emerge, it’s that he thinks all conscious animals are motivated to engage in play.
I feel this last answer maybe hasn’t answered all your questions but I was a bit confused by your last paragraph, which might have arisen out of an understandable misunderstanding of the claim about consciousness and play.
Can you have pure joy unconnected to a particular sensation? Maybe, but I’m sceptical. First, the closest I can imagine is calm joyful moments during meditation, or drug-induced euphoria, but in both cases I think it’s at least plausible there are associated sensations. Second, to me, even the purest moments of simple joy seem to be sensations in themselves, and I don’t know if there’s any conscious experience without sensations.
I would say thinking of something funny is often pleasurable. Similarly, thinking of something sad can be unpleasant. And this thinking can just be inner speech (rather than visual imagination). Inner speech is of course sensory, but it’s not the sensations of the inner speech, and instead your high-level interpretation of the meaning that causes the pleasure. (There might still be other subtle sensations associated with pleasure, e.g. from changes to your heart rate, body temperature, facial muscles, or even simulated smiling.)
Also, people can just be in good or bad moods, which could be pleasant and unpleasant, respectively, but not really consistently simultaneous with any particular sensations.
I would add that conscious sensation allows for more abstract processing of sensations, which enables tool use and other complex planning like long term planning in order to get the future self more pleasurable sensations. Humphrey doesn’t talk about that much, perhaps because it’s only a small subset of conscious species that have been observed doing those things, so perhaps mere consciousness isn’t sufficient to engage in them (some would argue you need language to do good long term planning and complex abstraction).
Maybe some other potential capacities that seem widespread among mammals and birds (and not really investigated much in others?) that could make use of conscious sensation (and conscious pleasure and unpleasantness):
episodic(-like) memory (although it’s not clear this is consciously experienced in other animals)
working memory
voluntary attention control
short-term planning (which benefits from the above)
FWIW, mammals seem able to discriminate anxiety-like states from other states.[1]
Animals do engage in play with unpleasant experiences, e.g., playfighting can include moderately unpleasant sensations.
I don’t think they are motivated to explore things they find unpleasant or aversive, or unpleasantness or aversion themselves. Rather, it just happens sometimes when they’re engaging in the things they are motivated to do for other reasons.
I suppose the benefits of those experiences being conscious might be to form more sophisticated strategies of avoiding them in future.
Ya, this seems plausible to me. But this also seems like the thing that’s more morally important to look into directly. Maybe frogs’ vision is blindsight, their touch and hearing are unconscious, etc., so they aren’t motivated to engage in sensory play, but they might still benefit from conscious unpleasantness and aversion for more sophisticated strategies to avoid them. And they might still benefit from conscious pleasure for more sophisticated strategies to pursue pleasure. The conscious pleasure, unpleasantness and desire seem far more important than conscious sensations.
Carey and Fry (1995) show that pigs generalize the discrimination between non-anxiety states and drug-induced anxiety to non-anxiety and anxiety in general, in this case by pressing one lever repeatedly with anxiety, and alternating between two levers without anxiety (the levers gave food rewards, but only if they pressed them according to the condition). Similar experiments were performed on rats, as discussed in Sánchez-Suárez, 2016, in section 4.d., starting on p.81. Rats generalized from hangover to morphine withdrawal and jetlag, from high doses of cocaine to movement restriction, from an anxiety-inducing drug to aggressive defeat and predator cues. Of course, anxiety has physical symptoms, so maybe this is what they’re discriminating, not the negative affect or aversive desire, although non-anxiolytic anticonvulsants didn’t block the effects, so convulsions in particular seem unlikely to explain the difference.
I would say thinking of something funny is often pleasurable. Similarly, thinking of something sad can be unpleasant. And this thinking can just be inner speech (rather than visual imagination)....Also, people can just be in good or bad moods, which could be pleasant and unpleasant, respectively, but not really consistently simultaneous with any particular sensations.
I think most of those things actually can be reduced to sensations; moods can’t be, but then, are moods consciously experienced, or do they only predispose us to interpret conscious experiences more positively or negatively?
(Edit: another set of sensations you might overlook when you think about conscious experience of mood are your bodily sensations: heart rate, skin conductivity, etc.)
But this also seems like the thing that’s more morally important to look into directly. Maybe frogs’ vision is blindsight, their touch and hearing are unconscious, etc., so they aren’t motivated to engage in sensory play, but they might still benefit from conscious unpleasantness and aversion for more sophisticated strategies to avoid them. And they might still benefit from conscious pleasure for more sophisticated strategies to pursue pleasure.
They “might” do, sure, but what’s your expectation they in fact will experience conscious pleasantness devoid of sensations? High enough to not write it off entirely, to make it worthwhile to experiment on, and to be cautious about how we treat those organisms in the meantime—sure. I think we can agree on that.
But perhaps we’ve reached a sort of crux here: is it possible, or probable, that organisms could experience conscious pleasure or pain without conscious sensation? It seems like a worthwhile question. After reading Humphrey I feel like it’s certainly possible, but I’d give it maybe around 0.35 probability. As I said in OP, I would value more research in this area to try to give us more certainty.
If your probability that conscious pleasure and pain can exist without conscious sensation is, say, over 0.8 or so, I’d be curious about what leads you to believe that with confidence.
I think most of those things actually can be reduced to sensations
What do you mean by “reduced to”? It’s tricky to avoid confounding here, because we’re constantly aware of sensations and our experiences of pleasure and unpleasantness seem typically associated with sensations. But I would guess that pleasure and unpleasantness aren’t always because of the conscious sensations, but these can have the same unconscious perceptions as a common cause.
Apparently even conscious physical pain affect (unpleasantness) can occur without pain sensation, but this is not normal and recorded cases seem to be the result of brain damage (Ploner et al., 1999, Uhelski et al., 2012).
moods can’t be, but then, are moods consciously experienced, or do they only predispose us to interpret conscious experiences more positively or negatively?
I’m not sure, and that’s a great question! Seems pretty likely these are just dispositions. I was also thinking of separation anxiety as an unpleasant experience with no specific sensations in other animals (assuming they can’t imagine their parents, when they are away), but this could just be more like a mood that disposes them to interpret their perceptions or sensations more negatively/threatening.
They “might” do, sure, but what’s your expectation they in fact will experience conscious pleasantness devoid of sensations? (...) If your probability that conscious pleasure and pain can exist without conscious sensation is, say, over 0.8 or so, I’d be curious about what leads you to believe that with confidence.
Thanks for pushing on this. There are multiple standards at which I could answer this, and it would depend on what I (or we) want “conscious” to mean.
With relatively high standards for consciousness like Humphrey seems to be using, or something else at least as strict as having a robust global workspace (with some standard executive functions, like working memory or voluntary attention control), I’d assign maybe 70%-95% probability to the in principle possibility based on introspection, studies of pain affect without pain sensation, and imagining direct stimulation of pleasure systems, or with drugs or meditation. However, I’d be very surprised (<15%) if there’s any species with conscious pleasure or unpleasantness without the species generally also having conscious sensations. It doesn’t seem useful for an animal to be conscious of pleasure or unpleasantness without also being conscious of their causes, which seems to require conscious sensation. Plus, whatever mechanisms are necessary for consciousness per se could be used for both perceptions/sensations and pleasure.
With low standards, e.g. a sensation is a perception + a belief that the perception matters, and pleasure is a positive judgement (as a belief), and low standards for what counts as a belief, I’d be less confident either way for both the in principle and in practice questions. I’d mostly have in mind similar intuitions, arguments and other evidence as above, but the evidence just seems weaker and less reliable here. But I’d also be more confident that frogs, fish and invertebrates have conscious pleasure and unpleasantness and conscious sensations.
You could also mix low standards for one but high standards for the other, but I’d give these possibilities less weight.
But I would guess that pleasure and unpleasantness isn’t always because of the conscious sensations, but these can have the same unconscious perceptions as a common cause.
This sounds right. My claim is that there are all sorts of unconscious perceptions an valenced processing going on in the brain, but all of that is only experienced consciously once there’s a certain kind of recurrent cortical processing of the signal which can loosely be described as “sensation”. I mean that very loosely; it even can include memories of physical events or semantic thought (which you might understand as a sort of recall of auditory processing). Without that recurrent cortical processing modeling the reward and learning process, probably all that midbrain dopaminergic activity does not get consciously perceived. Perhaps it does, indirectly, when the dopaminergic activity (or lack thereof) influences the sorts of sensations you have.
But I’m getting really speculative here. I’m an empiricist and my main contention is that there’s a live issue with unknowns and researchers should figure out what sort of empirical tests might resolve some of these questions, and then collect data to test all this out.
I do think blindsight is pretty compelling evidence for conscious visual sensation in species with regular sight and blindsight, as well as important evidence against conscious visual sensation in fish, frogs and reptiles, but I’m not sure what to make of it overall.
From Humphrey’s Aeon article:
So, fish, frogs and reptiles rely on a visual system that exists in humans (and other mammals and birds) that is not enough to generate conscious visual sensation in humans. The primary visual cortex seems necessary for conscious visual perception in mammals, and birds seem to have a functional analogue. (Are there studies of blindsight in birds?) On the other hand, fish, frogs and reptiles seem not to have any analogue. So, whatever functions or processes are necessary for conscious visual sensation in humans (and other mammals and birds) don’t seem to be realized in fish, frogs and reptiles.
However, I can imagine some possibilities that could undermine this argument:
The ancient system could have functions in fish, frogs and reptiles that the primary visual cortex in mammals has taken on, in a kind of evolutionary migration of some functions.
Whatever happens in the ancient system is not available in the “global workspace” in humans and so doesn’t result in conscious visual sensation, but it could be in fish, frogs and/or reptiles. It might be that the primary visual cortex and the cortex in general added extra layers before the global workspace and executive function, and there was no need for the ancient system to keep feeding directly into the global workspace in mammals and birds. So those connections were lost or replaced with connections that run through the primary visual cortex, which are lost or inactive in blindsight.
On the other hand, maybe fish, frogs and reptiles don’t have any global workspace at all, either. Nieder, 2022 writes “In contrast, reptiles and amphibians show no sign of either working memory or volitional attention. Surprisingly, some species of teleost fishes exhibit elementary working memory and voluntary attention effects suggestive of possibly rudimentary forms of subjective experience. With the potential exception of honeybees, evidence for conscious processing is lacking in invertebrates.” That being said, I don’t think he cites any negative results, so this is not evidence of absence, just absence of evidence. And the fact that some fish seem to have working memory and voluntary attention suggests those fish do have something like a global workspace, despite no cortex and these functions being realized in the human cortex.
Blindsighted humans do have conscious visual sensation, just not accessible for report.
Also related is Mason, G., & J. Michelle Lavery. (2022). What Is It Like to Be a Bass? Red Herrings, Fish Pain and the Study of Animal Sentience. Frontiers in Veterinary Science, 9. https://doi.org/10.3389/fvets.2022.788289
From the abstract:
Humphrey’s argument fish aren’t conscious doesn’t only rest on their not having the requisite brain structures, because as you say, it is possible consciousness could have developed in their own structures in ways that are simply distinct from our own. But then, Humphrey would ask, if they have visual sensations, why are they uninterested in play? When you have sensations, play can teach you a lot about your own sensory processes and subsequently use what you’ve learned to leverage your visual sensations to accomplish objectives. It seems odd that an organism that can learn (as almost all can) would evolve visual sensations but not a propensity to play in a way that helps them to learn about those sensations.
Perhaps fish just don’t benefit from learning more about their visual sensations. The sensations are adaptive, but learning about them confers no additional adaptive advantage. That seems a stretch to me, because it’s hard for me to imagine sensations being adaptive without learning and experimenting with them conferring additional advantage.
You could also respond by citing examples where fish can play, and are motivated to sensation-seek, as you already have, and I think if Humphrey believes your examples he would find that persuasive evidence about those organisms consciousness.
Does he spell out more why it’s useful to learn more about your own sensations? Also, couldn’t this apply to any perception that feeds into executive functions/cognitive control, conscious or not?
What if sensory play is just very species-specific? Do the juveniles of every mammal and bird species play? Would he think the species without play aren’t conscious, even if they have basically the same sensory neural structures?
A motivation to engage in (sensory) play has resource costs. Playing uses energy and time, and it takes energy to build the structures responsible for the motivation to play. And the motivation could be risky without a safe environment, e.g. away from predators or protection by parents and with enough food. Fish larvae don’t seem to get such safe environments.
I guess a thesis he’s stated elsewhere is that it’s the function of consciousness to matter. This is the adaptive belief it causes. So, conscious sensations should just be interesting to animals with them, and maybe without that interest, there’s no benefit to conscious sensation. This doesn’t seem crazy to me, and it seems pretty plausible with my sympathies to illusionism. Consciousness illusions should be adaptive in some way.
But, this only tells me about conscious sensation. Animals without conscious sensation could still have conscious pleasure, unpleasantness and desires, which realize the mattering and interest. And animals don’t engage in play to explore unpleasantness and aversive desire. So what are the benefits of unpleasantness and aversive desire being conscious as opposed to unconscious? And could there be similar benefits for conscious sensation? If there are, then sensory play may not be (evolutionarily) necessary for consciousness in general or conscious sensation in particular after all.
To me “conscious pleasure” without conscious sensation almost sounds like “the sound of one hand clapping”. Can you have pure joy unconnected to a particular sensation? Maybe, but I’m sceptical. First, the closest I can imagine is calm joyful moments during meditation, or drug-induced euphoria, but in both cases I think it’s at least plausible there are associated sensations. Second, to me, even the purest moments of simple joy seem to be sensations in themselves, and I don’t know if there’s any conscious experience without sensations.
Humphrey theorises that the evolutionary impulse for conscious sensations includes (1) the development of a sense of self (2) which in turn allows for a sense of other, and theory of mind. He thinks that mere unconscious perception can’t be reasoned about or used to model others because, being unconscious, it is inaccessible by the global workspace for that kind of use. in contrast, conscious sensations are accessible in the global workspace and can be used to imagine the past, future, or what others are experiencing. The cognitive and sensory empathy that allows can enable an organism to behave socially, to engage in deceit or control, to more effectively care for another, to anticipate what a predator can and can’t see, etc.
I would add that conscious sensation allows for more abstract processing of sensations, which enables tool use and other complex planning like long term planning in order to get the future self more pleasurable sensations. Humphrey doesn’t talk about that much, perhaps because it’s only a small subset of conscious species that have been observed doing those things, so perhaps mere consciousness isn’t sufficient to engage in them (some would argue you need language to do good long term planning and complex abstraction).
Humphrey believes that mammals in general do engage in play, which he thinks all (but not only) conscious animals do, and that they also engage in sensation-seeking (e.g. sliding down slopes or moving fast through the air for no reason), which he thinks only (but not all) conscious animals do. And he’d say the same thing about birds, and the fact that those behaviors’ distribution over species lines up nicely with the species with neural structures he thinks generates consciousness he treats as additional confirmation of his theory.
Animals do engage in play with unpleasant experiences, e.g., playfighting can include moderately unpleasant sensations. I suppose the benefits of those experiences being conscious might be to form more sophisticated strategies of avoiding them in future. It isn’t that Humphrey thinks play is necessary for conscious to emerge, it’s that he thinks all conscious animals are motivated to engage in play.
I feel this last answer maybe hasn’t answered all your questions but I was a bit confused by your last paragraph, which might have arisen out of an understandable misunderstanding of the claim about consciousness and play.
Thanks, this is helpful!
I would say thinking of something funny is often pleasurable. Similarly, thinking of something sad can be unpleasant. And this thinking can just be inner speech (rather than visual imagination). Inner speech is of course sensory, but it’s not the sensations of the inner speech, and instead your high-level interpretation of the meaning that causes the pleasure. (There might still be other subtle sensations associated with pleasure, e.g. from changes to your heart rate, body temperature, facial muscles, or even simulated smiling.)
Also, people can just be in good or bad moods, which could be pleasant and unpleasant, respectively, but not really consistently simultaneous with any particular sensations.
Maybe some other potential capacities that seem widespread among mammals and birds (and not really investigated much in others?) that could make use of conscious sensation (and conscious pleasure and unpleasantness):
episodic(-like) memory (although it’s not clear this is consciously experienced in other animals)
working memory
voluntary attention control
short-term planning (which benefits from the above)
FWIW, mammals seem able to discriminate anxiety-like states from other states.[1]
I don’t think they are motivated to explore things they find unpleasant or aversive, or unpleasantness or aversion themselves. Rather, it just happens sometimes when they’re engaging in the things they are motivated to do for other reasons.
Ya, this seems plausible to me. But this also seems like the thing that’s more morally important to look into directly. Maybe frogs’ vision is blindsight, their touch and hearing are unconscious, etc., so they aren’t motivated to engage in sensory play, but they might still benefit from conscious unpleasantness and aversion for more sophisticated strategies to avoid them. And they might still benefit from conscious pleasure for more sophisticated strategies to pursue pleasure. The conscious pleasure, unpleasantness and desire seem far more important than conscious sensations.
Carey and Fry (1995) show that pigs generalize the discrimination between non-anxiety states and drug-induced anxiety to non-anxiety and anxiety in general, in this case by pressing one lever repeatedly with anxiety, and alternating between two levers without anxiety (the levers gave food rewards, but only if they pressed them according to the condition). Similar experiments were performed on rats, as discussed in Sánchez-Suárez, 2016, in section 4.d., starting on p.81. Rats generalized from hangover to morphine withdrawal and jetlag, from high doses of cocaine to movement restriction, from an anxiety-inducing drug to aggressive defeat and predator cues. Of course, anxiety has physical symptoms, so maybe this is what they’re discriminating, not the negative affect or aversive desire, although non-anxiolytic anticonvulsants didn’t block the effects, so convulsions in particular seem unlikely to explain the difference.
I think most of those things actually can be reduced to sensations; moods can’t be, but then, are moods consciously experienced, or do they only predispose us to interpret conscious experiences more positively or negatively?
(Edit: another set of sensations you might overlook when you think about conscious experience of mood are your bodily sensations: heart rate, skin conductivity, etc.)
They “might” do, sure, but what’s your expectation they in fact will experience conscious pleasantness devoid of sensations? High enough to not write it off entirely, to make it worthwhile to experiment on, and to be cautious about how we treat those organisms in the meantime—sure. I think we can agree on that.
But perhaps we’ve reached a sort of crux here: is it possible, or probable, that organisms could experience conscious pleasure or pain without conscious sensation? It seems like a worthwhile question. After reading Humphrey I feel like it’s certainly possible, but I’d give it maybe around 0.35 probability. As I said in OP, I would value more research in this area to try to give us more certainty.
If your probability that conscious pleasure and pain can exist without conscious sensation is, say, over 0.8 or so, I’d be curious about what leads you to believe that with confidence.
What do you mean by “reduced to”? It’s tricky to avoid confounding here, because we’re constantly aware of sensations and our experiences of pleasure and unpleasantness seem typically associated with sensations. But I would guess that pleasure and unpleasantness aren’t always because of the conscious sensations, but these can have the same unconscious perceptions as a common cause.
Apparently even conscious physical pain affect (unpleasantness) can occur without pain sensation, but this is not normal and recorded cases seem to be the result of brain damage (Ploner et al., 1999, Uhelski et al., 2012).
I’m not sure, and that’s a great question! Seems pretty likely these are just dispositions. I was also thinking of separation anxiety as an unpleasant experience with no specific sensations in other animals (assuming they can’t imagine their parents, when they are away), but this could just be more like a mood that disposes them to interpret their perceptions or sensations more negatively/threatening.
Thanks for pushing on this. There are multiple standards at which I could answer this, and it would depend on what I (or we) want “conscious” to mean.
With relatively high standards for consciousness like Humphrey seems to be using, or something else at least as strict as having a robust global workspace (with some standard executive functions, like working memory or voluntary attention control), I’d assign maybe 70%-95% probability to the in principle possibility based on introspection, studies of pain affect without pain sensation, and imagining direct stimulation of pleasure systems, or with drugs or meditation. However, I’d be very surprised (<15%) if there’s any species with conscious pleasure or unpleasantness without the species generally also having conscious sensations. It doesn’t seem useful for an animal to be conscious of pleasure or unpleasantness without also being conscious of their causes, which seems to require conscious sensation. Plus, whatever mechanisms are necessary for consciousness per se could be used for both perceptions/sensations and pleasure.
With low standards, e.g. a sensation is a perception + a belief that the perception matters, and pleasure is a positive judgement (as a belief), and low standards for what counts as a belief, I’d be less confident either way for both the in principle and in practice questions. I’d mostly have in mind similar intuitions, arguments and other evidence as above, but the evidence just seems weaker and less reliable here. But I’d also be more confident that frogs, fish and invertebrates have conscious pleasure and unpleasantness and conscious sensations.
You could also mix low standards for one but high standards for the other, but I’d give these possibilities less weight.
This sounds right. My claim is that there are all sorts of unconscious perceptions an valenced processing going on in the brain, but all of that is only experienced consciously once there’s a certain kind of recurrent cortical processing of the signal which can loosely be described as “sensation”. I mean that very loosely; it even can include memories of physical events or semantic thought (which you might understand as a sort of recall of auditory processing). Without that recurrent cortical processing modeling the reward and learning process, probably all that midbrain dopaminergic activity does not get consciously perceived. Perhaps it does, indirectly, when the dopaminergic activity (or lack thereof) influences the sorts of sensations you have.
But I’m getting really speculative here. I’m an empiricist and my main contention is that there’s a live issue with unknowns and researchers should figure out what sort of empirical tests might resolve some of these questions, and then collect data to test all this out.