• Robb G. Best

Bird Brains: The Secret of Parrot Intelligence

Parrots: at times, they seem almost suspiciously smart. It’s not just about the talking and the mimicry; the Harvard Gazette reports that an adult parrot can routinely outperform a human four-year-old in a variety of cognition tests, including judging the relative volume of liquids. (Pour equal amounts of juice into a tall thin cup and a short stout one and your average preschooler will opt for the taller cup, while your average parrot won’t be fooled.)

How can a creature with a brain so noticeably different than our own seem to think so clearly? And why is parrot or crow intelligence (or, for that matter, octopus intelligence) so unsettling, compared to say, chimpanzee intelligence? What is it about a smart bird that seems a little spooky?

Science has yet to address the latter questions, but as to that first point, it appears that a breakthrough has been made. University of Alberta neuroscientists Cristián Gutiérrez-Ibáñez, Andrew N. Iwaniuk and Douglas R. Wylie have been hard at work, studying the brain structures in 98 different avian specimens.

Here's what they found. It’s true that the pontine nuclei, a brain area strongly connected to intelligence in primates like us, is very small in birds. However, as the University of Alberta paper notes, “In recent years, it has been increasingly recognized that complex cognitive abilities (or any behavior) cannot be assigned to a single brain structure; rather they arise from distributed neural systems.”

In this case, the neural systems in parrots appear to owe a lot to the medial spiriform nucleus (SpM). Compared to the pontine nuclei in primates, the SpM in birds is similar in structure and connectivity, but located in a different spot. Still, like the primate’s pontine nuclei, it circulates information from the cortex to the cerebellum and back again.

What’s happening here appears to be a case of convergent evolution. Consider how birds and bats both have wings. This is not because birds and bats share a common winged ancestor, but instead because flight is very advantageous, and wings are the most efficient way to achieve it. Parrots and primates each independently and over millennia developed a brain region that circulates data between the cortex and the cerebellum because that is an efficient way to support higher brain functions.

And in the same way that humans have an unusually developed pontine nuclei, parrot brains feature an enlarged SpM.

Viewing brain complexity as a function of an overall system instead of the product of a single fixed brain region might also explain octopus intelligence. (They carry most of their neurons distributed among their eight legs.) Considering all the stuff your feet come in contact with on a daily basis, let’s be glad convergent evolution didn’t wind up giving us limb-brains, too. We just have to deal with the ego blow of watching a parrot outsmart the darling four-year-olds in our lives--and dominate us when it comes to impressions.

#animals #biology

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