>The distinctness of g from many other valued personal characteristics was clearly recognized within ten years after Spearman discovered it. In 1915, one of Spearman’s doctoral students, E. Webb, published a factor analysis of a matrix of correlations including a number of highly g-loaded tests and a number of ratings of character, or personality. The particular personality traits chosen for study and obtained from ratings by students’ teachers and associates were actually selected because they were expected to be related to g, and hence to show significant loadings on the g factor. This expectation, however, was completely contradicted by Webb’s analysis, which yielded two wholly distinct factors— g and a general “character” factor, which Webb labeled w and characterized as “will” and “persistence of motives.” The types of items most highly loaded on the w factor were described as: perseverance, as opposed to willful changeability; perseverance in the face of obstacles; kindness on principle; trustworthiness; and conscientiousness. It seemed puzzling that this cluster of traits would emerge independent of g. Teachers’ and other people’s subjective impressions of any given person’s level of intelligence create a “halo effect” which biases the observers’ ratings of that person’s personality traits. Despite this bias of the personality ratings by halo effects, Webb’s factor analysis, because it included objective tests of g, gave a clean-cut separation of the two domains. What Webb’s study and subsequent studies seemed to indicate was that g, even as fallibly measured by psychometric tests, is an entirely cognitive variable.
Later studies of the relationship between personality factors and g have fully substantiated this conclusion.<