Drawing on research into social politics among chimpanzees, the cognitive development of children, and the ancient tools that have been found littered across the Rift Valley, in this program Dr. Alice Roberts explores how Homo sapiens developed such large brains—and asks why we are the only species of our kind left on the planet today. She also discusses how caring for large-brained offspring has shaped civilization, and the evolutionary adaptation that allows grandmothers to help raise their grandchildren.

A BBC Production.