Statistical Learning in Specific Language Impairment and Autism Spectrum Disorder: A Meta-Analysis

TLDR

Statistical learning deficits may underlie phonological and syntactic difficulties in SLI and could be a shared deficit with ASD, as suggested by the procedural deficit hypothesis. This meta‑analysis tested whether statistical learning deficits are common to individuals with SLI and ASD. The authors pooled effect sizes from 14 SLI and 13 ASD studies across six statistical‑learning tasks to compare diagnoses. SLI participants exhibited significant deficits (g = .47, 95 % CI .28–.66), whereas ASD participants performed comparably to controls (g = –.13, 95 % CI –.34 to .08), with no task‑ or age‑related moderation, indicating distinct underlying mechanisms for their social‑communicative difficulties.

Abstract

Impairments in statistical learning might be a common deficit among individuals with Specific Language Impairment (SLI) and Autism Spectrum Disorder (ASD). Using meta-analysis, we examined statistical learning in SLI (14 studies, 15 comparisons) and ASD (13 studies, 20 comparisons) to evaluate this hypothesis. Effect sizes were examined as a function of diagnosis across multiple statistical learning tasks (Serial Reaction Time, Contextual Cueing, Artificial Grammar Learning, Speech Stream, Observational Learning, Probabilistic Classification). Individuals with SLI showed deficits in statistical learning relative to age-matched controls g = .47, 95% CI [.28, .66], p < .001. In contrast, statistical learning was intact in individuals with ASD relative to controls, g = –.13, 95% CI [–.34, .08], p = .22. Effect sizes did not vary as a function of task modality or participant age. Our findings inform debates about overlapping social-communicative difficulties in children with SLI and ASD by suggesting distinct underlying mechanisms. In line with the procedural deficit hypothesis (Ullman & Pierpont, 2005), impaired statistical learning may account for phonological and syntactic difficulties associated with SLI. In contrast, impaired statistical learning fails to account for the social-pragmatic difficulties associated with ASD.