Today's human brain is 10% smaller than that of our Cro-Magnon ancestors, but scientists are divided on whether that means we are getting smarter or dumber. Some say it does represent a dumbing down, but that our increasingly complex society means individuals don't need as much intelligence to survive and reproduce. Others think it's a sign of domestication and lower aggression, pointing to cases of shrinking brain mass among some species as they become less violent, reports NPR. "Another way to say that is an increase in tolerance," said a Duke anthropologist.
One study compared the brains of chimpanzees and bonobos, noting that chimps have bigger brains, but bonobos are less aggressive and better at cooperating and teamwork. "The nice thing about studying animals and human nature is that it helps us design or think of some strategies that deal with our darker sides," said the anthropologist. (And in other fluffier brain-related news...)