Humans have more brain neurons than any other primate—but these extra neurons come at a price. Our brains consume 20% of our body's energy when resting, compared with 9% in other primates. Scientists have suggested that cooking may have helped humans get that extra energy while spending less time foraging—because cooking effectively predigests food, making it easier for our guts to absorb calories. Now, a new study supports this idea, finding that raw food alone wouldn't have allowed our ancestors' brains to grow: They would have had to spend more than 9 hours a day eating to get enough energy.
Join us for a live chat at 3 p.m. EST on Thursday, 8 November, on this page to discuss how cooked food might relate to bigger brains. You can leave your questions in the comment box below before the chat starts. The full text of the chat will be archived on this page.
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Suzana Herculano-Houzel is an associate professor at the Federal University of Rio de Janeiro, Brazil, where she heads the Laboratory of Comparative Neuroanatomy, and a scholar of the James McDonnell Foundation and of the Brazilian National Research Council (CNPq). Her main research interests are the evolutionary and developmental origins of the diversity of the nervous system across all sorts of animals, including humans.
Richard Wrangham is a professor of biological anthropology at Harvard University interested in chimpanzee behavioral ecology, the evolution of violence, the influence of cooking on human evolution, and the conservation of chimpanzees and other apes. He has studied wild chimpanzee behavior since 1987 as director of the Kibale Chimpanzee Project in Uganda.
Ann Gibbons is a correspondent for Science magazine, where she has covered human evolution for more than a decade.