Environmental & Science Education, STEM, Nature, Wildlife, Biodiversity, Behavior, Nature of Science
Ed Hessler
Bird brains continue to surprise. Two recent studies published in the journal Science, reported on in Scientific American find that "birds actually have a brain that is much more similar to our complex primate (brain) than previously thought." Bret Stetka and experienced writer on neurology walks us through both papers.
I've read only two or three other accounts reporting on this but Stetka seems to me to stick close to the science and what it claims, eschewing the sensational. Some highlights.
The assumption of a lack of a neocortex in bird brains--the seat of complex thinking and creativity--limited brain function in birds "The new findings,"from one of the papers, writes Stetka, " show that birds' do, in fact, have a brain structure that is comparable to netocortex despite taking a different shape. It turns out at a cellular level, the brain region is laid out much like the mammal cortex, explaining why many birds exhibit advanced behaviors and abilities that have long befuddled scientists.
The other paper, "lends still more insight into the avian brain, suggesting that birds have some ability for sensory consciousness," a feature "long thought to be localized in the cerebral cortex of smart primates--namely chimps, bonobos and us humans. The crows studied--Carrion crows--"appear to have at least a rudimentary form of sensory consciousness."
The researchers trained "two carrion crows...to recall a previous experiment to guide their behavior." Here is the sequence.
Upon completion of the training the carrion crows "went through a testing phase in which a gray square might appear followed by either a red or blue square 2.5 seconds later. In this exercise, the crows were trained to move their head if they saw a gray square and then a red one. And they learned to keep their head still if they saw a gray square and then a blue one. When the birds saw no stimulus followed by the appearance of a colored square, the sequence was reversed: blue signaled them to move their head, and red told them not to. So to correctly respond to the colored squares, the crows had to recall whether or not they had seen a gray one first—equating to a past subjective experience.
"It was crucial to the experiment to present the gray square in six different intensities, including at the threshold of the birds’ perception. This way," the research team," could confirm that the crows were not simply carrying out conditioned responses to stimuli but instead drawing on a subjective experience.
The activity was also recorded and monitored through implanted electrodes in the brain.
Neato!
The researchers make no claim about whether the "crows have the self-conscious existence and self-awareness of apes but simply that the birds can partake in a unique, multipart sensory experience in response to a stimulus." Stetka includes a powerful, on the money quote from the team's lead researcher: “I am generally not a big fan of ascribing complex humanlike cognitive states to animals and prefer to maintain a conservative attitude. Humans easily start to project their own mental states to other living (or even nonliving) beings. But in terms of sensory consciousness in other species, it is probably fair to assume that advanced vertebrates, such as mammals and birds, possess it.”
Bird brains not as simple as once thought!
Here is a link to the original papers: the first (consciousness in crows) and the second (cortex-like circuit in avians). You can learn more about the authors, the institutions and details about the research.
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