ITHACA, N. Y. — A recent study by researchers at Cornell University found that vertebrate brains differ in many ways, but that size is the key to developing a more advanced brain.
The authors of the study, Jordan Moore Ph.D., a postdoctoral fellow at Columbia University and Timothy DeVoogd, a professor of psychology at Cornell University, studied 58 species of songbirds and noted the differences in brain size and abilities.
They found that once a species developed a brain of a certain size, it could develop advanced pathways that gave it more advanced abilities. Brain regions that controlled the mouth and beak of some birds, and allowed for song making, for example, developed additional neural networks the larger they grew.
The authors tried to take their findings and apply them to human brain evolution, positing that perhaps humans developed a larger brain than any of our early competitors, then adapted enhanced regions that controlled different abilities, such as the universal human superpower: language.
“Most neuroscientists believe there is nothing special about the way that our brains have evolved, that what we need to do is understand the principles that underlie brain evolution in general, which is what this study involves,” explains DeVoogd in a news release. “The way you build a bigger brain is not just making everything bigger but rather slowing down or lengthening late pieces of development.”
Bigger brains generally have a more developed cortex, which is key for memory, attention, perception, higher thought, awareness, and other executive functions. The cortex is believed to have evolved last in the humanoid brain.
Before this study, two competing theories explained brain development and evolution in humans. One was that natural selection necessitated the progressive changes in certain areas of the brain to get a leg up on humanity’s early wild competitors and predators. The other, which DeVoogd and Moore’s study supports, posits that some species evolved a larger brain first, then enlisted different parts of it to perform certain actions.
While brain size explained some differences in different bird species’ abilities, there were other factors at play. Birds that could produce more complex and varied songs had larger areas of the brain that controlled songs. The brain areas that controlled the face and mouth were larger in bird species with short, fat beaks that eat primarily seeds than in birds with longer beaks that eat mostly insects.
The study was published in the Proceedings of the Royal Society B.