Study offers new look at why our brains evolved to be so big

This 1885 photo shows a side view of a human brain. In relation to body size, our brains are huge, about six times larger than one would expect from other mammals. And this three-pound organ sucks up fully 20 percent of the body’s energy needs. (Oscar G. Mason/J.C. Dalton/Philadelphia, Lea Brothers & Co. via AP)

NEW YORK — Why do people have such big brains? Some researchers asked a really powerful brain — a computer — and got back a surprising answer.