“Paul Broca, for example, was a famous French craniologist in the nineteenth century whose name is given to Broca’s area, the part of the frontal lobe involved in the generation of speech (which is wiped out in many stroke victims). Among his other interests, Broca used to measure brains, and he was always rather perturbed by the fact that the German brains came out a hundred grams heavier than French brains. So he decided that other factors, such as overall body weight, should also be taken into account when measuring brain size: this explained the larger Germanic brains to his satisfaction. But for his prominent work on how men have larger brains than women, he didn’t make any such adjustments. Whether by accident or by design, it’s a kludge.”