In the face of little concrete evidence, it wasn’t totally unreasonable to assume that the bigger the brain, the more intelligent the head that held it.
Gradually, though, doubts about that simple equation have begun to creep in. The brains of Neanderthal man were larger than the brains of Homo sapiens. Surely they couldn’t have been smarter than we are, could they? And then we’ve been discovering that dumb animals can do all sorts of things that we can’t. Birds can navigate half-way around the world without getting lost and without the help of even an old-fashioned compass. Dogs can hear things we can’t, and bees can see colors we don’t. Dolphins can communicate with each other. So even can trees. Then we discovered that some parrots can correctly use as many words as the average two-year old.
And now, using MRI scans, scientists have found that female brains are more efficient than male brains. The brain of the average woman is 8% smaller than the average male brain. But research isn’t suggesting that men are 8% smarter. Research from both the Universities of California and Madrid have found that on the whole men have better spatial intelligence than women. (So when they won’t stop and ask for directions, maybe they aren’t as lost as we women think they are.) Women, however, outperform men in inductive reasoning, are better at keeping track of a changing situation and at some numerical tasks.
Ah, but not to worry: Trevor Robbins, professor of cognitive neuroscience at Cambridge University in England says that the finding was fascinating, but controversial.