Open material for Developmental trajectory of syntax comprehension by persons with intellectual disability

The aim was to investigate whether a progressive dissociation between the cognitive level and syntax comprehension occurs during the development of persons with intellectual disabilities (ID). Two cross-sectional developmental trajectory analyses were successively conducted. Study 1 comprised 615 typically developing participants and 615 participants with ID. Their total scores on a syntax comprehension test were regressed on a nonverbal cognitive measure and the slopes of the two groups’ regression lines were compared. In Study 2, logistic regression curves of the two groups for each of the 92 test items were compared. Results showed only negligible between-groups differences of developmental trajectories, whatever the level of analysis. The idea of a progressive dissociation between cognitive level and receptive syntactic skills of people with ID is not confirmed. However, a syntax test evaluating more complex sentences than those used in this study might show such a dissociation.