Gist-based illusions within and across stimulus modalities in autism spectrum disorder

Some studies have reported a low rate of False Recognition (FR) in individuals with Autism Spectrum Disorder (ASD) relative to non-autistic comparison participants. This finding however, has not always been replicated and the source of the discrepancy remains unknown. We hypothesised that poor episodic memory functions may account for this finding. We used an adapted version of the DRM paradigm which presents lists of Words, Pictures or Word-Picture Pairs to obtain measures of performance which reflect episodic (Hits and False Alarms - FA) and semantic (FR) memory functions. Results showed a decreased rate of FR in ASD individuals with lists of Words which rose above the rate seen in non-autistic comparison participants with lists of Word-Picture pairs. This increased rate of FR in ASD was accompanied by a parallel increase in Hits and a decrease in FA which reached a similar level in the two groups. Poor episodic memory functions may prevent individuals with ASD from acquiring item information which in turn precludes the formation of semantic links between items. This could render them less prone to FR.