The factorial structure of executive functions in preschool and elementary school children and relations with intelligence.

The timing of structural changes in executive functions (EFs) across development is a matter of controversy; whereas some studies suggest a uniform structure of EFs in early childhood, findings in middle and late childhood are mixed. There are results indicating uniformity of EFs as well as several studies suggesting multidimensionality of the construct. In addition, studies demonstrate an age-related differentiation of the relation between EFs and intelligence. We conducted a comparative analysis of the EF structure and relations with fluid intelligence in two distinct age groups. A sample of n = 145 preschool children (5.2-6.7 years of age) and n = 109 elementary school children (8.8-11.8 years) completed measures of working memory, inhibition, cognitive flexibility, and fluid intelligence. Confirmatory factor analysis (CFA) revealed that a single-factor model best represented performance on EF tasks in both preschool and elementary school children. Multi-group CFA indicated equivalent and strong relations between EFs and intelligence across both age groups (r = .64 in preschool and elementary school children). Our results confirm that EFs are significantly related to fluid intelligence but might not underlie a uniform pattern of successive differentiation into multiple EF components in childhood. We discuss how methodological artifacts such as simultaneous interference might have contributed to previous findings on differentiation in middle and late childhood.