Executive functions and intelligence from the CHC theory perspective: Investigating the correspondence between the WAIS-IV and the NAB Executive Functions Module.

Substantial overlap between executive functions (EFs) and intelligence has been reported. Yet further research is required with respect to how the specific components of the two constructs are interrelated. The present study was aimed at exploring the relationship between EFs and intelligence by examining the latent structure of the Wechsler Adult Intelligence Scale (WAIS-IV) and the Executive Functions Module from the Neuropsychological Assessment Battery (NAB). The aim was also to test the correspondence of the two measures to the Cattell-Horn-Carroll (CHC) theory. 205 healthy participants, aged 18-89 years, were administered the NAB and WAIS-IV. Confirmatory factor analysis (CFA) was employed to explore the latent constructs underlying the two test batteries. Models based on the current WAIS-IV index structure showed worse model fit than models based on the CHC theory. In particular, factors representing broad CHC abilities comprehension knowledge (Gc), fluid reasoning (Gf), visual processing (Gv), processing speed (Gs), and working memory capacity (Gwm) proved model fit improvement. The best model fit, however, provided a five-factor model combining the Gf and Gwm abilities into one factor and additionally including a retrieval fluency (Gr) factor. The results demonstrate strong relationships between the WAIS-IV and the NAB Executive Functions Module and suggest substantial overlap between EFs and intelligence within the CHC framework. Nevertheless, according to the recent update of the CHC theory, the NAB fluency tasks may represent a distinct EF factor comprising Gr abilities independent from the WAIS-IV.