Biological Aspects of a High Socio-Economic Group

Data are presented on the social backgrounds and IQs of a sample of scientists, their male sibs and their fathers. The range of IQ in the scientists is similar to the range of scores expected of the higher 25% of a representative general population sample. The IQs of the scientists showed a positive correlation with social class. Differences in IQ between the scientists and their fathers in each social class are related to the distance the scientists have moved up the social scale. In the twenty-two families in which the IQs of the father and two male sibs are known the upwardly mobile sibs tend to have higher IQs than the non-mobile or downwardly mobile sibs. In Class II there is evidence that stabilizing selection operates on IQ to maintain the mean IQ level. The effect on social stratification of such selection, together with increased educational opportunity, is discussed.