Sensitivity to communicative and non-communicative gestures in adolescents and adults with autism spectrum disorder: saccadic and pupillary responses.

Nonverbal communication using social cues, like gestures, governs a great part of our daily interactions. It has been proposed that people with autism spectrum disorder (ASD) show a deviant processing of social cues throughout their social cognitive development. However, social cues do not always convey an intention to communicate. Hence, the aim of this study was to test the sensitivity of adolescents and adults with ASD and neurotypical controls to social cues of high communicative (pointing) and low communicative values (grasping). For this purpose, we employed a spatial cueing paradigm with both Cue Types and compared saccadic reaction times (SRTs) between conditions in which the target appeared at a location which was congruent versus incongruent with the direction of the cue. Results showed that both adolescents and adults with ASD had slower SRTs for the incongruent relative to the congruent condition for both Cue Types, reflecting sensitivity to these cues. Additionally, mental effort during the processing of these social cues was assessed by means of pupil dilation. This analysis revealed that, while individuals with and without ASD required more mental effort to process incongruent compared to the congruent cues, cues with higher communicative value posed more processing load for the ASD group. These findings suggest that the perception of social gestures is intact in ASD but requires additional mental effort for gestures with higher communicative value.