Autism and Hierarchical Models of Intelligence

Area of Science:

• Psychometrics
• Neurodevelopmental Disorders
• Child Psychology

Background:

• The Wechsler Intelligence Scale for Children (WISC) uses a hierarchical model with statistically independent index scores.
• The independence of WISC index scores in autistic samples is not well-established.

Purpose of the Study:

• To investigate the statistical independence of WISC index scores in children with autism.
• To compare data-driven factor analyses with WISC manual-derived index scores in autistic and typically developing children.

Main Methods:

• Factor analysis was performed on WISC-IV and WISC-V subtest data from children with autism.
• Exploratory factor analysis results were compared to manual-derived index scores.
• A typically developing WISC-IV cohort was included for comparison.

Main Results:

• The WISC-IV typically developing cohort demonstrated expected factor-score independence.
• Autistic samples (WISC-IV and WISC-V) showed reduced independence between data-driven factors and manual index scores.
• Working memory significantly influenced multiple index scores in autistic individuals, unlike in the normative sample.

Conclusions:

• WISC index scores lack the desired statistical independence in autistic samples.
• Working memory significantly impacts multiple WISC index scores in autistic children, particularly in the WISC-V.
• Findings suggest caution when interpreting WISC scores for autistic individuals.