Executive function in Williams and Down syndromes

► We examine executive function (EF) in Williams (WS) and Down (DS) syndromes. ► We employ analogous verbal and visuospatial EF tasks, across four EF domains. ► We compare the performance of the two groups with a typically developing group. ► The results for each group varied according to task modality and EF domain. ► Individuals with WS were more susceptible to the effect of task modality.