Eye movements reveal a dissociation between memory encoding and retrieval in adults with autism

Abstract

People with Autism Spectrum Disorder (ASD) exhibit subtle deficits in recollection, which have been proposed to arise from encoding impairments, though a direct link has yet to be demonstrated. In the current study, we used eye-tracking to obtain trial-specific measures of encoding (eye movement patterns) during incidental (natural viewing) and intentional (strategic) encoding conditions in adults with ASD and typical controls. Using this approach, we tested the degree to which differences in encoding might contribute to recollection impairments, or whether group differences in memory primarily emerge at retrieval. Following encoding of scenes, participants were asked to distinguish between old and similar lure scenes and provide 'remember'/'familiar' responses. Intentional encoding increased eye movements and subsequent recollection in both groups to a similar degree, but the ASD group were impaired overall at the memory task and used recollection less frequently. In controls, eye movements at encoding predicted subsequent correct responses and subsequent recollection on a trial-by-trial basis, as expected. In contrast, despite a similar pattern of eye movements during encoding in the two groups, eye movements did not predict trial-by-trial subsequent memory in ASD. Furthermore, recollection was associated with lower similarity between encoding- and retrieval-related eye movements in the ASD group compared to the control group. The eye-tracking results therefore provide novel evidence for a dissociation between encoding and recollection-based retrieval in ASD.