Newfound brain structure explains why some birds are so smart—and maybe even self-awa

Newfound brain structure explains why some birds are so smart—and maybe even self-aware

Virgina Morell

Never before has “bird brain” been such a compliment: In recent years, birds have been found to make tools, understand abstract concepts, and even recognize paintings by Monet and Picasso. But their lack of a neocortex—the area of the mammalian brain where working memory, planning, and problem solving happen—has long puzzled scientists. Now, researchers have found a previously unknown arrangement of microcircuits in the avian brain that may be analogous to the mammalian neocortex. And in a separate study, other researchers have linked this same region to conscious thought.

So, he and colleagues used a test similar to one that probes primates for signs of consciousness—a state of mind thought to arise with the sudden activation of certain neurons. They trained two lab-raised, 1-year-old carrion crows to move or stay still in response to a faint cue displayed on a monitor. When correct, the birds were rewarded. The scientists then implanted electrodes in the crows’ brains to record their neuronal signals as they responded. When the crows reacted, their neurons fired, suggesting they had consciously perceived the cue; but when they didn’t, their neurons were silent. The neurons that fired in agreement with the crows’ action were located in the pallia, the researchers report today, also in Science. Nieder calls this “an empirical marker of sensory consciousness in birds’ brains,” similar to that seen in primates.

That’s certain to stir debate, as “some researchers argue that consciousness is uniquely human,” says Irene Pepperberg, a comparative psychologist at Harvard University known for her work with Alex, an African gray parrot who communicated in English about abstract concepts. Pepperberg was not involved in these new studies but finds them “really exciting."

In more detail ->

A neural correlate of sensory consciousness in a corvid bird

Andreas Nieder et al

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.

Newfound brain structure explains why some birds are so smart—and maybe even self-aware

Virgina Morell

" They trained two lab-raised, 1-year-old carrion crows to move or stay still in response to a faint cue displayed on a monitor. When correct, the birds were rewarded. The scientists then implanted electrodes in the crows’ brains to record their neuronal signals as they responded. When the crows reacted, their neurons fired, suggesting they had consciously perceived the cue; but when they didn’t, their neurons were silent."

I find this conclusion by the researchers to be very puzzling. Surely at least some neurons in the crows' brains would be expected to fire if they respond as trained to the visual cue. Regardless of whether the crows are conscious or not. It theoretically could be just a neural but non-conscious stimulus/response circuit developed through the training. Even in humans such things are routine, for instance with a trained typist the pressing of the correct letter key based on the stimulus of seeing the letter written on the written sheet being transcribed. The response is non-conscious and automatic; it has to be in order for the typist to do 65 words per minute. 

And much more primitive animals have also been trained many times to respond to particular visual patterns. For instance fish. I think also reptiles and amphibians. Operant conditioning like that used to be the stock and trade of behaviorists, who mostly believed animals are not conscious.  

A deeper problem with this: the researchers evidently believe that the crows aren't conscious unless they (the researchers) can detect neurons firing in the crows' brains. That looks like a case of deep materialist neuroscientific conditioning on the part of the researchers.  

This is not to say that the crows aren't conscious - I think that they almost certainly are, but this research doesn't seem to reveal anything important about it. 

I share your concerns, @nbtruthman. A digital camera can respond to a cue such as subject motion and cause the firing of an autofocus circuit, adjusting the setting of the lens as a result. This is of a similar class to the light inside a fridge coming on when the door is opened. It is nonsensical to suggest that such stimulus-response actions represent consciousness on the part of the camera or the refrigerator.

The difficulty with consciousness always comes back to the same thing, we know what it is, and what it isn't, but tracing it to any cause is not particularly practical. Interpretation of such things as apparent correlations seems mostly dependent on prior expectations.