Relationship between Working Memory and Externalizing Behaviors in Children from a Clinical Population: an Exploration of the Role of Expressive Language and Anxiety

Abstract Objective This study investigated the role of expressive language and anxiety in the relationship between working memory and externalizing behaviors in the pediatric clinical population. Method 80 archived cases were randomly selected from a private practice (Male: 73.7%; Age M = 4.75, SD = 1.57). All participants were diagnosed with at least one neurodevelopmental disorder (e.g., ASD: 47.5%; ADHD: 33.8%; GDD: 16.3%). The Externalizing Problems Index and Anxiety Subscale Scores from BASC-3, the Working Memory Index Score from SB-5, and the Expressive Language Subscale Score from Vineland-3 were used. A moderated mediation model was proposed, with expressive language mediating working memory and externalizing behaviors, anxiety moderating the relationship between working memory and expressive language, and gender and age being covariate variables. The analysis was performed by using the Hayes’ PROCESS Model 7 for SPSS. Results The full moderated mediation model was statistically significant (ω = 0.005, 95% CI [0.001, 0.009]). Specifically, expressive language mediated the relationship between working memory and externalizing behavioral problems for children with low anxiety (ωLow = −0.191, 95% CI [−0.330, −0.058]) and moderate anxiety (ωModerate = −0.144, 95% CI [−0.248, −0.044]), but not in those with high anxiety (ωHigh = −0.059, 95% CI [−0.139, 0.002]). Conclusion The study provided empirical evidence for the mediating effect of expressive language on the relationship between working memory and externalizing behaviors, which was moderated by anxiety in children. It suggested that improving expressive language skills may help reduce externalizing behaviors in children with low to moderate anxiety.