Evaluating the Neural Correlates of Intention Understanding in Autism Spectrum Disorder

Background:  Deficits in high level social cognitive skills such as joint attention and theory of mind are well documented in children with Autism Spectrum Disorder (ASD). However, the behavioral literature is equivocal to whether children with ASD have the ability to engage in lower level social cognitive skills such as recognizing others as acting intentionally. These equivocal findings may be partially explained by the varying methodology used to assess the construct termed ‘intention’ across studies. When children with ASD are simply required to attend to actions on an object to infer another’s intention, studies reliably find intact intention understanding abilities. In contrast, when tested using paradigms that require children with ASD to attend to social-communicative cues (e.g., facial expressions, gaze, etc.) to draw conclusions regarding intention, impairment in intention understanding is identified. This study uses Event-Related Potentials (ERPs), a measurement of brain activity with millisecond resolution, to build upon the behavioral literature to better understand how different types of intention are processed at a neurological level in individuals with ASD.

Objectives:  The purpose of this study was to use ERPs to assess, for the first time, the neural correlates of intention understanding in children with ASD and controls. Given behavioral research suggesting that ASD is associated with impaired intention understanding only when cued using social stimuli (e.g., facial expressions, gaze, etc.), this study compared differences in neural processing between groups across social and non-social stimuli.

Methods:  We examined neural indices of social and non-social intention understanding in 22 school-age ASD children and 22 controls (age, gender, and IQ matched). Participants viewed picture sequences depicting either social or non-social intention. The final picture of the sequence varied such that an actor either completed the intended action (expected) or performed an unintended action (unexpected). We evaluated the P600 as it has been linked to expectancy violations in visual scene processing. Participants made button press responses to intended condition only.

Results:  Social stimuli: Both groups demonstrated similar ERP responses, characterized by a greater (positive) P600 to unintended vs. intended condition. Response accuracy was significantly worse for the ASD group. Non-social stimuli: No group differences were identified in either response accuracy or ERP responses (greater P600 to unintended vs. intended condition).

Conclusions:  Accuracy data concord with previous behavioral findings of a dissociation between social and non-social intention understanding, such that social intention alone is functionally impaired in ASD. However, no group differences were observed for either stimuli type at a neurological level. This is a particularly novel finding, as it demonstrates that observed behavioral impairments are independent from the neural processes supporting basic social intention understanding. Additional work is necessary to characterize this newly identified gap between neurological functioning and overt behavior.