Brain size and intelligence in man.
The relationship between brain size and intelligence was investigated in two ways. Cranial capacity was measured in people with known IQs. A very small correlation was found between cranial capacity and intelligence; but this was shown to be the result of the confounding effects of height. A large series of brains was also investigated, data being obtained on occupation from the case notes. When the effects of body height and weight were controlled for, it was possible to demonstrate a statistically significant, but very slight, relation between brain size and occupational group.