Breadth of knowledge is the single factor within human control that contributes most to academic achievement and general cognitive competence. In contradiction to the theory of social determinism, breadth of knowledge is a far greater factor in achievement than socioeconomic status. The positive correlation between achieved ability and socioeconomic status is only half the correlation between achieved ability and the possession of general information. That is to say, being "smart" is more dependent on possessing general knowledge than on family background per se.10
