Fossil study: vision, not frontal lobe, drove primate brain evolution

A Duke-led fossil study finds primates' neocortex expansion was driven by vision, not frontal-lobe growth, overturning a long-held idea about brain evolution. Published in Science, researchers used virtual endocasts from skulls of living and extinct primates. They found frontal lobes scaled with overall brain size, while visual regions expanded disproportionately alongside larger optic nerves. The findings date anthropoids' large brains to at least 33 million years ago, linked to high-acuity vision. Potential drivers include social communication or foraging efficiency.