Understanding Social Versus Private Intention: Exploring the Neural Correlates of Intention Understanding Based on Intentional Content

Background:   Given that children with ASD demonstrate impairment in social-cognition, developing a comprehensive understanding of intention understanding in ASD is important as it is believed to be a foundational skill upon which higher level social-cognition is built. Recent behavioral work in young children with significant ASD symptomatology suggests that while deficits are not present on tasks requiring intent to be inferred from an actor’s action on an object (private intention), impairment is evident on tasks in which intent must be inferred from the actor’s social-communicative behavior such as eye gaze, vocalizations, or facial expressions (social intention). However, it is unclear whether the neural correlates supporting each type of intention are distinct. 

Objectives:  The purpose of this study was to validate a novel ERP paradigm to assess the neural correlates of private and social intention understanding that could be used to examine these constructs in children with ASD. As part of this validation process, we examined the relationship between the neural correlates of each type of intention understanding and autistic traits. 

Methods:   We examined neural indices of attention to social and non-social intention understanding in 35 typically developing young adults, exploring modulation of each type of intention understanding by level of autistic traits. Participants viewed a sequence of pictures depicting either social or private intention with the final picture of the sequence varying such that sometimes the actor completed the intended action and sometimes he performed an unintended action. Participants made a response only if the actor did what he intended to do; no responses were made to unintended actions. Autistic traits in this non-clinical sample were quantified using the Broader Autism Phenotype Questionnaire.

Results:   Across participants, there was a main effect of trial type, such that unintended actions resulted in greater allocation of attention — as indexed by larger P3 amplitude — compared to intended actions, and a main effect of intentional content, such that private intention stimuli resulted in greater allocation of attention — as indexed by larger P3 amplitude —  compared to social intention stimuli. An interaction between trial type and intentional content was also observed, which indicated that the difference in P3 amplitude between intended and unintended actions was greater for private than for social stimuli. Higher expression of autistic traits, specifically aloofness, was correlated with an attenuated allocation of attention — as indexed by smaller P3 amplitude — for social intention understanding, but was unrelated to private intention understanding. 

Conclusions:  Neuroelectric indices of attention concord with behavioral findings of a dissociation between social and private intention understanding, and highlight that it is the processing of social intention in particular that is related to ASD traits. Notably, the attenuated allocation of attention for social intention understanding observed at higher levels of autistic traits seems to suggest that social intention stimulus cues (i.e., eye gaze and head turn) fail to induce a strong sense of expectancy for these individuals. This finding demonstrates that attenuated responsiveness to social-communicative cues extends to autistic characteristics within the range of typical functioning.