Factor structure of nonverbal cognition

The unity and diversity of executive functions: A systematic review and re-analysis of latent variable studies

Confirmatory factor analysis (CFA) has been frequently applied to executive function measurement since first used to identify a three-factor model of inhibition, updating, and shifting; however, subsequent CFAs have supported inconsistent models across the life span, ranging from unidimensional to nested-factor models (i.e., bifactor without inhibition). This systematic review summarized CFAs on performance-based tests of executive functions and reanalyzed summary data to identify best-fitting models. Eligible CFAs involved 46 samples (N = 9,756). The most frequently accepted models varied by age (i.e., preschool = one/two-factor; school-age = three-factor; adolescent/adult = three/nested-factor; older adult = two/three-factor), and most often included updating/working memory, inhibition, and shifting factors. A bootstrap reanalysis simulated 5,000 samples from 21 correlation matrices (11 child/adolescent; 10 adult) from studies including the three most common factors, fitting seven competing models. Model results were summarized as the mean percent accepted (i.e., average rate at which models converged and met fit thresholds: CFI ≥ .90/RMSEA ≤ .08) and mean percent selected (i.e., average rate at which a model showed superior fit to other models: ΔCFI ≥ .005/.010/ΔRMSEA ≤ -.010/-.015). No model consistently converged and met fit criteria in all samples. Among adult samples, the nested-factor was accepted (41-42%) and selected (8-30%) most often. Among child/adolescent samples, the unidimensional model was accepted (32-36%) and selected (21-53%) most often, with some support for two-factor models without a differentiated shifting factor. Results show some evidence for greater unidimensionality of executive function among child/adolescent samples and both unity and diversity among adult samples. However, low rates of model acceptance/selection suggest possible bias toward the publication of well-fitting but potentially nonreplicable models with underpowered samples. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

What can be localized in the brain? Toward a "factor" theory on brain organization of cognition

A theoretical integration attempt among the lesional (neuropsychological), physiological (functional), and psychometric models of cognition is presented in this article. Recent neuroimaging techniques particularly fMRI have shown that there are some brain functions (i.e., simple) that can be localized into single brain areas whereas there are others (i.e., complex) that cannot. Clinical neuropsychology has been able to propose some "cognitive factors" based on empirical observations in patients with brain lesions. Factor analysis in psychometry may provide an additional tool to extract some constitutive elements of psychological functions (factors). "Factors" in factor analysis, however, may have different levels of specificity. Some times they refer to functional systems (complex cognition); in other occasions to elements of cognition ("cognitive factors"). It is emphasized that the very same brain areas (and cognitive factors) may be potentially involved in different types of cognition. It is proposed that complex cognition depends on specific patterns of activation of different brain areas and specific circuitries ("modules"), each one making its own contribution to the whole system (functional system). Impairment in a specific cognitive factor, on the other hand, may result in diverse types of impairments. At the moment, it seems feasible to suppose some cognitive factors responsible for normal neuropsychological performance. Theoretically, the impairment in any of these factors could be responsible for some specific neuropsychological syndromes.