III. THE IMPORTANCE OF GENERAL INTELLIGENCE FOR SCHOOL PROGRESS
If we examine mentally the large numbers of retardates in any public school where attendance is compulsory, we find that by far the majority of them are inferior in general intelligence. A child of superior general intelligence (IQ) is seldom found among retardates. Of children of 120 IQ and over, Terman reports that they are almost invariably at least up to grade. Whatever the vicissitudes of fate—illness, absence, special disability—a child of superior general capacity manages to hold his own, at least.
It is not true, however, that the superior child is allowed, under the undifferentiated curriculum, to make full use of his power. He is compelled to slow down to the typical progress of his group, and to use only a portion of his capacity for learning. It is rare to find a superior child who is doing “a full day’s work” in school, because the tasks assigned do not call for maximum effort. Superior children could easily do much more than is allowed.
General intelligence is, then, the single most important factor for school progress. The same may be said of progress in vocational careers. The life success of a human being may be said to depend upon general intelligence, character, health, and opportunity (including the factor of sex). If any of these factors is reduced to zero, so that the individual is totally lacking in intelligence, character, health, or opportunity there can be no achievement. The order of importance of the various factors is probably that in which they have been mentioned, with general intelligence certainly at the top of the list. Intelligence may create character, opportunity, and even health, but none of these can create intelligence.