Toward an understanding of adult intellectual development: investigating within-individual convergence of interest and knowledge profiles.

To further our understanding of the role interests play in the development of adult intellect, this study examines the relationship between intraindividual differences in interest and knowledge profiles. On the basis of a sample of 330,154 individuals, results show a moderate, positive average intraindividual correlation between interest and knowledge that increases as individuals age and is stronger for men than for women. Consistent with recent theories regarding the development of adult intelligence, expertise, and talent, these results demonstrate that noncognitive intraindividual differences can add to one's understanding of the acquisition of knowledge and skills. The current findings regarding the intraindividual convergence of interests and knowledge substantiate K. Murphy's (1998) call for renewed research on interests and point to the usefulness of an intraindividual perspective in applied psychology.