Implicit Learning of Children With and Without Developmental Language Disorder Across Auditory and Visual Categories

The current study examined implicit sound- and visual-meaning-mappings of children with and without Developmental Language Disorder (DLD). One child with DLD and 29 children with typical language development (TLD) were included in the study, based on results from a hearing screening and standardized assessments of cognitive and expressive language skills. Participants completed two computer-based experiments, which were designed to investigate: 1) sound discrimination (pitch and duration), implicit mapping of sound stimuli to objects; 2) visual discrimination, implicit mapping of visual stimuli to objects. The current study showed that children with TLD who implicitly learned pitch categories showed better mapping of sound stimuli to objects than children with TLD who implicitly learned duration categories. The one child with DLD who learned pitch categories showed implicit learning in the mapping task. The child also showed implicit learning of visual stimuli in the visual experiment. An association between sound-discrimination scores and sound mapping performance in multivariate analyses of covariance (MANCOVAs) was not found in the TLD group. An interaction between visual discrimination and phase in the test block was found. Correlation tests revealed a negligibly positive association between visual discrimination and visual learning of the second phase in the test block in the TLD group, suggesting that links were starting to appear as children learned the categories. Findings are discussed in the context of recruitment challenges, and potential experimental design adjustments are suggested for future work