Abstract
A central feature of autism spectrum disorder (ASD) is an impairment in ‘social attention’ — prioritized processing of socially-relevant information. For example, people with ASD do not show the same visual interest in (and biased processing of) the eyes and face. Beyond such specific cues, however, socially relevant stimuli are preferentially attended in a broader categorical sense: in particular, observers orient preferentially to people and animals (compared to inanimate objects) in complex natural scenes (New, Cosmides, & Tooby, 2007, PNAS). To determine the scope of social attention deficits in autism, we explored whether this bias was evident in people with ASD (both children and adults, with IQs ranging from 56 to 140). In each trial, observers both with and without ASD viewed alternating versions of a natural scene, and had to ‘spot the difference’ between them. This difference involved either an animate object (a person or animal) or an inanimate object (a plant or artifact) that either reversed its orientation or repeatedly disappeared and reappeared. Participants were not made aware of these categories, and change detection performance (in terms of both speed and accuracy) was measured as an index of automatic attentional prioritization. Control participants without ASD showed prioritized attention to people and animals, replicating previous work. This could not be explained by lower-level visual factors, since the effect disappeared when using blurred or inverted images. Our primary discovery was that individuals with ASD also showed the same prioritized social attention for animate categories. This prioritized social attention increased slightly with age, and was generally unrelated to their clinically-evaluated social abilities. These results suggest that social attention — and its impairment in autism — is not a unitary phenomenon: specific impairments in processing faces and eyes may occur despite the intact categorical prioritization of visual social information.