Intelligence Evolved at Least Twice in Vertebrate Animals

Summary

The findings emerge in a world enraptured by artificial forms of intelligence, and they could teach us something about how complex circuits in our own brains evolved. Perhaps most importantly, they could help us step “away from the idea that we are the best creatures in the world,” said Niklas Kempynck, a graduate student at KU Leuven who led one of the studies. “We are not this optimal solution to intelligence.” Birds got there too, on their own. Pecking Disorder For the first half of the 20th century, neuroanatomists assumed that birds were simply not that smart. The creatures lack anything resembling a neocortex — the highly ordered outermost structure in the brains of humans and other mammals where language, communication and reasoning reside. The neocortex is organized into six layers of neurons, which receive sensory information from other parts of the brain, process it and send it out to regions that determine our behavior and reactions. In the 1960s, the neuroanatomist Harvey Karten’s research into avian neural circuits changed how the field viewed bird intelligence. “For the longest time, it was thought that this is the center of cognition, and you need this kind of anatomy to develop advanced cognitive abilities,” said Bastienne Zaremba, a postdoctoral researcher studying the evolution of the brain at Heidelberg University. Rather than neat layers, birds have “unspecified balls of neurons without landmarks or distinctions,” said Fernando García-Moreno, a neurobiologist at the Achucarro Basque Center for Neuroscience in Spain. These structures compelled neuroanatomists a century ago to suggest that much of bird behavior is reflexive, and not driven by learning and decision-making. This “implies that what a mammal can learn easily, a bird will never learn,” Güntürkün said. The conventional thinking started to change in the 1960s when Harvey Karten, a young neuroanatomist at the Massachusetts Institute of Technology, mapped and compared brain circuits in mamm...