Associations between Simple and Complex Executive Function skills and adaptive function in a sample of 3‐year‐olds enriched for variation in autism and ADHD traits

BACKGROUND: Adaptive Functioning-including communication, socialization, and daily living skills-predicts outcomes and quality of life for individuals who are autistic or have ADHD, yet its cognitive underpinnings in early development remain poorly understood. Executive Functions (EFs) are a plausible mechanism linking developmental level or IQ to Adaptive Functioning, but prior work in preschoolers has relied largely on parent-reported EF measures, which are vulnerable to shared method variance with parent-reported Adaptive Functioning. Here, we examine associations between performance-based EF and parent-reported Adaptive Functioning among 3-year-olds enriched for variation in autism and ADHD traits. METHODS: One hundred and twenty-nine children (109 with a family history of autism and/or ADHD) completed six EF tasks, reduced through factor analysis to scores for Simple EF (pertaining to simple response inhibition, holding information in mind, and applying a rule) and Complex EF (involving complex response inhibition, shifting response in accordance with a new task set, and updating information). Adaptive Functioning was assessed using the Vineland Adaptive Behavior Scales-Second Edition. Autism traits, ADHD traits and developmental level were measured using the SRS-2, CBCL-Preschool, and MSEL, respectively. Hierarchical regression models tested whether each EF index was positively associated with Adaptive Functioning, and whether these effects remained after controlling for developmental level, autism traits, and ADHD traits. RESULTS: Both Simple and Complex EF were positively associated with Adaptive Functioning (β = .293, .316). While associations between Simple EF and Adaptive Functioning were accounted for by general developmental level, Complex EF showed associations with Adaptive Functioning above and beyond developmental level, autism, and ADHD traits. CONCLUSIONS: EFs in general, and Complex EF in particular, represent a promising, developmentally-sensitive target for early support in the toddler or preschool years, which could positively impact the day-to-day functioning of children with a family history of autism/ADHD, or already showing elevated autism traits.