Behavioural flexibility of children with Autism Spectrum Disorder on a card-sorting task with varying task difficulty

Inflexibility is taken to be a key characteristic of Autism Spectrum Disorder (ASD), although it is unclear which aspect of cognitive functioning is critical in this context. The current study investigated task-switching problems and inflexibility with a group of children with ASD, and a mental-aged matched control group. Participants (n = 50; mean age = 7 years) completed two card-sorting tasks, which involved learning to sort by either two or three possible dimensions, and then the sorting rule was switched although the number of dimensions required to sort the cards remained the same. Following the sorting rule change, the ASD group made more errors compared to controls. Errors were also related to task type (two or three dimensions), but this was not found to interact with ASD. If poor performance were solely dependent on executive function (working memory) problems in ASD, then a steeper decrease in performance with an increase in task difficulty for one group, compared to another group, would be expected. The current results suggest that task difficulty is an aspect of importance in set-shifting, but shifting is not differentially affected by this component.