Intelligence and Specific Cognitive Abilities in Children

This community-based study investigated the relationships between measures of specific cognitive functions (such as working memory [WM] and interference control) and intelligence in 283 8- to 11-year-old children, including 124 children who fulfilled criteria for a psychiatric diagnosis. A hierarchical regression analysis was used to overcome issues of overlapping predictor constructs. The results generally showed that measures of processing speed, WM, as well as inhibitory interference control entered in the order of presentation, each contributed uniquely to the explanation of fluid intelligence performance. The results for crystallized intelligence performance generally showed that the measures of processing speed, short-term memory ( STM), WM, and sustained attention-entered in that order-made significant independent contributions. While effect sizes varied somewhat for contributions in the whole sample compared with the subgroup not meeting criteria for a psychiatric diagnosis, there were no significant differences. The findings therefore should be broadly representative in indicating that the unique aspects of these cognitive functions are important in the explanation of intelligence. The findings also demonstrate important independent features of the functions used as predictors.