Intelligence and Cognitive Development: Three Sides of the Same Coin

Abstract

Research on intelligence, mainly based on correlational and factor-analytical work, research on cognitive development, and research in cognitive psychology are not to be opposed as has traditionally been the case, but are pursuing the same goal, that is, understand how the human being adapts to his/her own, complex environment. Each tradition of research has been focusing on one source of variation, namely situational differences for cognitive psychology, individual differences for psychometrics, and age differences for developmental psychology, while usually neglecting the two other sources of variation. The present paper compares those trends of research with respect to the constructs of fluid intelligence, working memory, processing speed, inhibition, and executive schemes. Two studies are very briefly presented to support the suggestion that tasks issued from these three traditions are very similar, if not identical, and that theoretical issues are also similar. We conclude in arguing that a unified vision is possible, provided one is (a) interested in the underlying processes and not only in the experimental variations of conditions; (b) willing to adopt a multidimensional view according to which few general mechanisms are at work, such as working memory or processing capacity, inhibition, and executive schemes; and (c) granting a fundamental role to individual differences.

Keywords: attentional control; cognitive development; individual differences; inhibition; intelligence; processing capacity; working memory.

Figure 1

Regression and commonality analyses: Piagetian tasks. Assessment 1 for those tasks (Year 2 of the longitudinal study). Children aged 6–11 years, N = 100. Age and working memory tasks were used as predictors on each of the Piagetian tasks. Commonality analyses were then conducted to assess the variance due uniquely to each predictor and the shared variance. The figure displays the average value across the Piagetian tasks, for the total variance (Panel a) and for the age-related variance only (Panel b).

Figure 2

Regression and commonality analyses: Raven’s task (Children and young adults). Children aged 8–12 years and young adults (20–30 years of age), N = 262. Age, as well as working memory, processing speed and inhibition tasks were used as predictors on the Raven task. Commonality analyses were then conducted to assess the variance due uniquely to each of the four groups of predictors and to their shared variance (two by two, three by three and all four predictors). (Panel a): total variance. Only variance accounted by several predictors together was very important, in particular Age and Speed together (6%), Speed and Working Memory (WM) (5%), Age, Speed and WM (34%), all four groups (10%). (Panel b): Age-related variance: Speed and WM together explained about two thirds of the age-related variance (66%).