[Footnote 1: Cattell: "A Statistical Study of Eminent Men," _Popular Science Monthly_, vol. LXII. pp. 375-77.]
In the facts of higher variability among males, and the hitherto restricted social opportunities provided for women are to be found the chief reasons for the comparatively high achievement of the male sex as compared with the female. But on the average the difference between the two sexes with respect to mental capacity is slight.
THE INFLUENCE OF RACE. A second factor in determining individual differences in mental traits is race. There are certain popular presuppositions as to the inherent differences in the mental activity of different races. The Irishman's wit, the negro's joyousness, the emotionality of the Latin races, the stolidity of the Chinese, are all supposed to be fundamental. And in a sense they are. That is, in the life and culture of these groups, such traits may stand out distinctively. But most psychologists and anthropologists question seriously whether these traits are to be traced to radical differences in racial inheritance. For the most part they seem rather to be the result of radical differences in environment. "Many of the mental similarities of an Indian to Indians and of his differences from Anglo-Saxons disappear, if he happens to be adopted and brought up as an Anglo-Saxon."[1]
[Footnote 1: Thorndike _loc. cit._, p. 52.]
There have been various experimental studies made to determine how much divergences in the mental activity of different races are determined by differences in racial inheritance. Such experiments have been conducted chiefly upon very simple traits and capacities. The accuracy of sensory response among different races has, for example, been examined. There have proved to be, in regard to these, slight differences in the effectiveness and accuracy of response. There are racial differences in hearing, as tested by the ticking of a watch or clock artificially made. In this test, Papuans, to take an instance, were inferior to Europeans. The sense of touch has been similarly tested, and comparatively negligible differences have been found. In regard to the five senses, their efficiency seems to be about equal in all the races of mankind. The proverbial keenness of vision of the Indian, for example, is found to be due to a superior training in its use, a training made imperative by the conditions of Indian life. In reaction time tests--that is, tests in the speed of simple mental and motor performances--the time consumed in response has been found to be about the same for all races tested. The results have been similar with regard to certain simple processes of judgment or inference: