Perception/action coupling in children with autism: insights from looking time and pupil dilation measurements

The objective of this study was to characterize, through indices extracted from eye-tracking measurements, the spontaneous distinction of videos of daily actions with a variable perception/action coupling, depending on whether, for the same action, the video was presented in the forward reading direction (strong coupling), or in the backward reading direction (weaker coupling). 17 pairs of videos of daily actions performed by adults were viewed by 36 typically developing children and 28 children with ASD aged 7-18 years. During the exposure phase, they watched two videos of the same action (forward and backward) presented successively, before looking at these two videos in competition, in a second visual preference phase. During the exposure phase, all participants paid similar general attention to each of the videos. We found greater pupillary dilation for backward than forward actions in both groups, but significantly less in the ASD group. In the visual preference phase, both groups showed significantly greater looking times for backward actions over forward ones, with no difference between groups. If TD children perceived the kinematics of the backward videos as violating their expectations given the strong perception/action coupling they had already built over that action, on the contrary, the lower increased in pupil dilation found in ASD children could reflect altered perception/action coupling. This study confirms the validity of looking time and pupil dilation as behavioral and physiological markers that could be used in a 10-mn eye-tracking test to explore perception/action coupling in childhood and in ASD. Lay summaryPeople with ASD often have difficulty understanding the actions of others. The fine understanding of actions requires a coupling between the action we observe, and its representation stored in our memory. This process might be challenged in autism. Here we used a 10-mn eye-tracking test to explore perception/action coupling in ASD. Participants were watching videos of daily actions. Looking time and pupil dilation were measured while participants watched videos of daily actions, and were found to be relevant indexes.