Preference for Social Motion in Autistic Adults

Autism is often linked to attenuated social attention, including a lowered looking preference for biological motion in autistic compared to non-autistic children. This looking preference has been suggested as an autism marker in childhood. However, few studies have investigated whether this bias persists into adulthood. Furthermore, the underlying cognitive mechanism of this group difference is largely unknown. Pupillary responses have been established as an index of salience processing and are thus a promising measurement of the cognitive bases of looking preference. The present study examined differences in looking preference and pupillary responses to social versus geometric motion between autistic and non-autistic adults (N = 66). In terms of preference, autistic adults demonstrated a reduced spontaneous looking toward social stimuli compared to the non-autistic group. Whereas the former displayed no clear preference for either motion type, the latter showed a strong preference for social motion. In terms of pupillary responses, the autistic group showed faster and larger pupil dilation for social motion compared to the non-autistic group, which indicated heightened cognitive effort and arousal. These results suggest persistent differences in social attention across the developmental lifespan in autism.