Collect all the facts that can be collected about the life of Racine and you will never learn from them the art of his verse
Regardless of how wisely we may use our brains, there’s no disputing that they are extraordinarily big. The average human brain weighs in at about three pounds, or 1,350 grams. Our closest living relatives, the chimpanzees, have less than one-third as much brain—just 384 grams. And if you compare the relative size of brains to bodies, our brains are even more impressive.
As a general rule, mammal species with big bodies tend to have big brains. If you know the weight of a mammal’s body, you can make a fairly good guess about how large its brain will be. As far as scientists can tell, this rule derives from the fact that the more body there is, the more neurons needed to control it. But this body-to-brain rule isn’t perfect. Some species deviate a little from it. A few deviate a lot. We humans are particularly spectacular rule breakers. If we were an ordinary mammal species, our brains would be about one-sixth their actual size.
Competing theories seek to explain the value of a big brain. One idea, championed by psychologist Robin Dunbar of the University of Oxford, is that complicated social lives require big brains. A relatively large-brained baboon can make a dozen alliances while holding grudges against several rivals. Humans maintain far more, and more complicated, relationships.
