Proceedings of the Annual Meeting of the Cognitive Science Society

Attention Deficit and Hyperactivity Disorder (ADHD) is a neuropsychiatric condition with a neurodevelopmental coursethat often persists in adulthood. Although it is conceptualised as a categorical disorder, ADHD traits are present in thegeneral population. ADHD constitutes an important paradigm because its aetiology is related to both frontal and striatalcircuits, but it is unclear what localised operations could be at fault when ADHD symptoms arise. We present a study where50 adults, of which 14 had a diagnosis of ADHD, performed a speeded and unspeeded variation of the Wisconsin CardSorting Test (WCST) and completed a set of questionnaires, including the Conners Adult ADHD Rating Scales (CAARS).Results indicate that sorting errors on the WCST did not differ between groups. However, when response times werecharacterised in terms of parameterised ex-Gaussian distributions for the unspeeded part of task, moderate correlationswere found between the parameter corresponding to the thickness of the tail of the distribution and subscales of theCAARS measuring inattention and impulsivity. This suggests that inattention and/or impulsivity explain the occasionalslower responses of ADHD participants. We consider the results in the context of an existing computational model thatsimulates cortical and basal ganglia operation in the WCST, where a qualitative exploration supports a distinction betweencortical and striatal components of the psychological processes that lead to performance of participants with ADHD traits.