Unity and diversity of the executive functions in early adolescents from Iran: alternative factor structures and invariance across age and socioeconomic status

Abstract

Executive functions (EFs) are cognitive skills that regulate thoughts and behavior. The unity and diversity model of EF, one of the most prominent frameworks in this field, proposes the existence of three correlated but separable EF domains (inhibition, updating and switching). This fractionation of EF has been shown from adolescence on in some, but not all studies, which usually only reported a few of many possible factor structures. Additionally, age and socioeconomic status (SES) effects in these studies were unreliable due to lack of invariance testing, necessary to ensure that participants of different ages/SES perform tasks similarly so that these effects can be estimated. Hence, we tested this framework in 407 9-15-year-old Iranians of variable SES using a test battery that includes two tasks for each EF domain and allows cultural adaptations regarding language and stimuli. We tested various alternative model configurations (one, two and three factor, nested and bifactor-S-1 models) using Confirmatory Factor Analyses and, for the selected best fitting model, performed invariance testing (across age and SES) with Multiple Indicators, Multiple Causes model. The best fitting model solution (three-correlated factors) replicated prior results in early adolescent samples from different countries, speaking to the universality of the separability of the three EF domains at this age. Furthermore, this model exhibited differential item functioning for only one of 7 indicators (for age and SES) allowing us to reliably show that all three EF latent traits improve with age, while SES exerts only minimal positive effects on shifting and updating.