Strategies for Social and Nonsocial Visual Information Processing in Autistic Children and Adolescents

Background: Individuals with Autism Spectrum Disorder (ASD) present both an atypical and distinctive visuo-perceptual profile (Mottron et al., 2006; Bertone et al., 2010).  Despite marked social and behavioural impairments, individuals with ASD often excel at tasks requiring the local analysis of detailed information and preferentially attend to the constituent parts of a stimulus rather than its whole form. It remains unknown, however, whether a bias for such local analysis is at the origin of other aspects of the social cognitive phenotype in ASD, such as facial information processing (Behrmann et al., 2006; Bertone et al., 2010, Weigelt 2012). 

Objectives: To assess local and global visual processing strategies used during social (face identity discrimination task - Exp 1) and non-social (Navon task - Exp 2) visuo-perceptual tasks in the same group of autistic and non-autistic children and adolescents.

Methods: 30 autistic and 31 non-autistic children and adolescents (6-15 years) performed a face identity discrimination (Exp 1) and Navon task (Exp 2) under conditions favouring either a local or global analysis. In Exp 1, participants completed a socially-laden, facial identity discrimination task using synthetic, computer-generated face images (Wilson et al., 2002). These face images consisted of simplified (hair and skin texture removed), ecologically-validated stimuli, extracted from traditional face photographs in both frontal (“front”) and 20° side (“side”) viewpoints. Performance was measured using face identity discrimination thresholds for conditions where the target and choice faces were presented in the same view, biasing a local analysis (front-front or same-view condition), and in different views, biasing a global analysis (front-side or view-change condition) (Morin et al., 2012). Local and global visual processing for nonsocial information was assessed for the same participants in Exp 2 using the Navon task (Navon 1977): a local and global hierarchical, compound letter task. Participants completed a focused attention version of the task, where they responded to either local or global features of the stimuli in two separate conditions. Performance was measured in terms of accuracy and reaction time.

Results:  Comparable between-group performances were found for the social, face identity discrimination task (Exp 1) in both local and global conditions. For the non-social, Navon task (Exp 2), the autism group performed significantly worse in the global condition, reflected by a higher error rate and slower average reaction time. When performance was assessed for the same participants across social and nonsocial tasks, decreased performance in the view-change condition of the face identity discrimination task was significantly correlated with increased error rate in the global condition of the non-social, Navon task.

Conclusions:  While the findings reveal a pattern of local precedence for non-social information processing only (Exp 2), correlations across social and nonsocial tasks suggest that autistics may use a similar strategy for the processing of both social and nonsocial information during childhood and adolescence. With ongoing data collection, we aim to further assess the role that development and/or experience may play in this relationship from the school-age years through to adulthood.