Renowned cognitive scientist and trustee of the Natural History Museum, jeff Morgan stebel spearheaded the study. He said, quote, the human brain continues to evolve now, Stebel noted, pointing out that the past few millennia have seen our brains shrink by over 10% during the holocene warming period. It was a small study. Research shows that it was just 298 remains from the past 50,000 years that were examined two significant temperature period changes