Decomposing response times in Williams syndrome in separate cognitive processes

Abstract

Williams Syndrome (WS) is a rare neurodevelopmental disorder of genetic origin. The syndrome is characterised by a selective set of deficits in a number of cognitive domains. In spite of a wealth of studies, response times (RTs) of WS have attracted little attention. In the present study, we fill this gap by analysing data from a receptive vocabulary task using the Diffusion Decision Model (DDM). Our results show that the speed of accumulation, decision threshold and non-decision time parameters of WS individuals are similar to these of typically developing 5-year-old preschoolers. In addition, WS verbal intelligence scores were associated with the speed of accumulation of lexical information. Finally, the performance of WS and preschooler individuals was correlated across the vocabulary task and an additional orientation discrimination task only at the group but not at the individual level; therefore, pointing to domain-specific lexical and perceptual processing in WS.