Reward Anticipation and Processing of Social Versus Nonsocial Stimuli in Children with and without Autism Spectrum Disorders

Background:  How children respond to social and nonsocial rewards has important implications for understanding both typical and atypical social cognitive development. Individuals with autism spectrum disorders are thought to process rewards differently than typically developing individuals. Specifically, previous theories suggest that children with autism may have less motivation to engage in social interactions because social stimuli are not rewarding. However, there is little direct evidence to support this claim, and previous studies have not controlled for reward or stimulus properties.

Objectives:  The current study was designed to measure reward anticipation and processing in children with and without autism while controlling for both reward and stimulus properties. We wished to clarify whether children with autism demonstrated deficits in reward anticipation and processing to both social and nonsocial stimuli, or whether these deficits were confined to social stimuli only.

Methods:   We utilized event-related potentials (the stimulus-preceding negativity, SPN and feedback-related negativity, FRN) to measure differences in reward anticipation and processing during a guessing game in 6-10-year-olds with (N = 20) and without (N = 23) a diagnosis of autism. Children were presented with reward indicators accompanied by incidental face or non-face stimuli. Non-face stimuli were comprised of scrambled faces in the shape of arrows, controlling for low level properties of the two conditions.

Results:  Children with autism showed significantly smaller responses while both anticipating and processing social rewards compared to typically developing children. However, reward anticipation and processing on nonsocial rewards was intact. Correlations between severity of autism symptomology and brain activity measures suggested that children who experienced more reward anticipation for nonsocial stimuli had more severe autism symptoms. 

Conclusions: While typically developing children find a face stimulus more rewarding than a non-face stimulus, children with autism do not. This is the first study to measure both reward anticipation and processing in children with and without autism while controlling for reward properties across conditions. These findings provide evidence that children with autism have reward anticipation and processing deficits for social stimuli only, rather than global reward deficits. Further, while our electrophysiological results suggest a lack of reward value to social stimuli in autism, our correlational findings reveal that perhaps children who are overly rewarded by nonsocial stimuli have more severe symptoms of autism. Thus, it might be the case that an overabundance of nonsocial motivation may occur at the expense of social motivation in children with autism.