Visual input, not frontal lobes, drove primate brain growth

A new study finds that increased visual information, not frontal lobe expansion, drove brain growth in monkeys, apes, and humans. Led by Duke's Richard Kay, researchers used CT scans of fossil skulls to show the frontal lobe grew predictably with overall brain size, while vision-processing regions expanded disproportionately, matching larger optic openings in monkeys, apes, and tarsiers. The finding challenges prior beliefs that frontal lobes drove primate intelligence. Kay suggests social communication or foraging efficiency as possible evolutionary drivers behind the vision-brain connection.