Many neuroscience experiments rely on reporting from humans for their results. Some theories actually argue that what is conscious is almost defined by an ability to report it. This has been limiting for research with other species. A research group at the University of Tübingen trained some crows to report their conscious experiences by moving their heads in response to a stimulus and they have correlated the perception with the firing of brain cells.
Subjective experiences that can be consciously accessed and reported are associated with the cerebral cortex. Whether sensory consciousness can also arise from differently organized brains that lack a layered cerebral cortex, such as the bird brain, remains unknown. We show that single-neuron responses in the pallial endbrain of crows performing a visual detection task correlate with the birds’ perception about stimulus presence or absence and argue that this is an empirical marker of avian consciousness. Neuronal activity follows a temporal two-stage process in which the first activity component mainly reflects physical stimulus intensity, whereas the later component predicts the crows’ perceptual reports. These results suggest that the neural foundations that allow sensory consciousness arose either before the emergence of mammals or independently in at least the avian lineage and do not necessarily require a cerebral cortex.https://science.sciencemag.org/content/369/6511/1626
This isn’t surprising to me. The researchers conclude that sensory consciousness is not limited to “only primates or other mammals possessing a layered cerebral cortex.” If the capability derived from a common ancestor, this result “would date the evolution of consciousness back to at least 320 million years when reptiles and birds on the one hand, and mammals on the other hand, evolved from the last common stem-amniotic ancestor.” A short explanation of the study is here.
Like you I’m not particularly surprised. There’s been discussion of bird consciousness for years. It’s nice to have more evidence, but I find the attention this particular study is receiving a bit puzzling. Still, it’s an interesting study.
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Did you notice the sort of double check in the protocol? I don’t think it is explained well and I may be misinterpreting it, but it seems like the crows not only had to see the stimulus but they also had to react to a cue that told them whether they should report it or not. They not only had to see it but they had to know they were seeing it to react appropriately to the cue. It seems like you would really have to contort yourself to explain how it would be some kind of mindless reaction.
I did see that. I agree it does ensure that the crows aren’t reacting reflexively. (Although I’m not sure anyone still believed they would be.) It’s also a test that requires a high degree of intelligence.
I also found it interesting the the bird analogue of the prefrontal cortex, the nidopallium caudolaterale, is in the back of their pallium.
By the way, did you see this article on the claustrum?
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I hadn’t seen that but it is interesting. I don’t see the relationship to Salvinorin A since the salvia experience isn’t anything like sleeping. It could be that it is triggering a large number of slow waves that is modifying an overall more complex pattern without fully replacing the faster patterns.
In general, I’m thinking rhythmic neural patterns is just what neurons do but faster more complex patterns are associated with consciousness. The conscious patterns seem to be overlays of theta, alpha, beta, and gamma.
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I guess this study may be seen as a “baby steps” way to potentially help push the quite anthropocentric “self report” adherents, a bit closer to the rest of us. My favorite example of them comes in the form of Lisa Feldman Barrett’s popular “theory of constructed emotion”. It holds that we don’t feel things like sadness unless other humans teach us to. Of course we humans are sooo special! I’m instead of the opinion that “the blind watchmaker” added all sorts of phenomenal traits to get various qualia driven forms of life to function more effectively in their own domains.
As for speculation that birds might have independently evolved a capacity for consciously accessing and reporting their subjective experiences, and so their consciousness and our consciousness didn’t spring from the same well, I highly doubt this. I’m more in the Feinberg and Mallatt camp here. Maybe octopuses or spiders evolved their capacity for qualia independently, but not birds.
“I guess this study may be seen as a “baby steps” way to potentially help push the quite anthropocentric “self report” adherents, a bit closer to the rest of us”.
Oddly I didn’t see this called out in the paper unless I missed it. But that was what immediately struck me more so than the evidence of consciousness itself.
Regrading how it arose in evolution, I am with Llinás in that I think it is property of neurons and nervous systems, although it requires some critical mass (TBD) before it fully manifests. So I think it would be found in most arthropods as well as birds. cephalopods, mammals, and maybe others. The main requirement is locomotion that integrates information about the environment with senses.