Factor analyses on the validity of the Wechsler measures of cognitive functioning
Beginning over a century ago, intelligence has been and currently is one of the most widely studied phenomena in the field of psychology. Still, there is a lack of consensus in the field on the definition and conceptualization of intelligence with researchers developing numerous theories to better understand it. Corollary to the debate over the concept of intelligence itself, methods of reliably measuring intelligence are also of concern. The widespread use of intelligence testing in a variety of settings, including educational, clinical, and private practice puts this point in sharp relief. Given the widespread use of intellectual assessments, it is imperative that practitioners utilizing such assessments are well-versed in the instruments, including what cognitive abilities are measured and how to interpret the results. The Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V), the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV), and the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) are three related cognitive assessment measures developed to assess general intelligence and a combination of several broad abilities: verbal comprehension (Gc), visual-spatial processing (Gv), fluid reasoning (Gf), short-term working memory (Gwm), and processing speed (Gs). The Wechsler cognitive assessment instruments were developed with theories and cognitive models from several domains, including cognitive psychology, neuropsychology, and specific cognitive abilities such as memory, attention, and executive functioning. However, it is debated whether the factor structure of the Wechsler instruments measures the cognitive abilities as outlined by the test publishers. The primary purpose of the present study was to examine the factor structure of the Wechsler cognitive assessment instruments against two models of cognitive abilities. The models examined were the CHC Theory of Intelligence and the Functional-CHC Model of Cognitive Ability to determine which model best fits the sample data from the Wechsler standardization samples. The data analyses included multiple exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) of the Wechsler standardization samples for each instrument. The present study attempted to provide a more comprehensive understanding of general intelligence and cognitive abilities in children, adolescents, and adults. Results of the present study provided support for some of the hypothesized broad abilities posited by both the F-CHC model and the CHC theory, particularly Gc, Gr/Gf, Gcm/Gwm, Gv, and Gs. Results also provided partial support for some of the hypothesized narrow abilities. However, the Wechsler instruments utilized do not appear robust enough to truly investigate the validity of the full F-CHC model and all the narrow abilities. This limitation and others are discussed as well as implications and future research directions.