Reading Intention in Action: The Case of Autism Spectrum Disorder

Background:  Autistic traits span a wide spectrum of behavioral departures from typical function including impairments in communication, presence of restricted behaviors and difficulties in social interaction. It is a common experience that effective interaction with others often relies on the ability to decode others’ intention. Recent evidence suggests that individuals with ASD have difficulties in anticipating the subsequent part of an action chain. To note, these anticipation difficulties emerge not only when performing the action (Fabbri-Destro et al., 2009), but also when observing someone else performing it (Cattaneo et al., 2007).

Objectives:  The aim of the present study was twofold: 1. To test whether ASD children would be able to read someone else’s intention from movement kinematics; 2. To test whether ASD children would be better at generating predictions about actions that are similar to their own.

Methods:  Nineteen high functioning children with ASD (17 boys) as well as 17 TD children (13 boys) matched on age, IQ full scale and handedness participated in the study. The participants with ASD fulfilled DSM-5 (APA, 1994) criteria for autistic disorders. All participants were requested to observe video-clips of a hand reaching and grasping a bottle to either place it into a container or pour its content into a glass. Participants had to identify the intention underlying the observed movement. Crucially, video-clips were edited as to occlude the final part of the action, therefore participants could rely only on visual kinematics of the initial part of the action. To examine whether TD and ASD children use knowledge of their own kinematics to generate predictions, we manipulated the degree of similarity between the kinematics of the observer and the kinematics of the observed agent. Thus, in two separate blocks, we administered video-clips of movements performed by either TD or ASD children. In each block, video-clips for both pouring and placing action (50%-50%) were presented randomly. Block order was counterbalanced across participants. We assessed children’s performance using t-tests on signal detection theory measures.

Results:  The analyses revealed that ASD children’s performance was at chance level in identifying the underlying intention. In contrast, a significantly above-chance identification rate was found for TD children (p<.05). Indeed, TD children were able to predict how the action would have unfolded even if presented only with its initial part. When contrasting performance for the two blocks separately, results indicated that neither TD nor ASD children were significantly better in predicting their own compared to others’ movement (p_s<.05)

Conclusions:  Overall, these findings are consistent with the idea that impaired social skills in ASD may - at least partially – be explained by anomalies in intention recognition from movement observation. Further analyses will test whether these anomalies correlate with motor execution abilities or with the severity of social symptoms in the attempt to shed light on the complex relationship between action execution, intention understanding and social skills in autism.