Social perception and social abilities: Relationships between action perception and autistic traits

Vision scientists have historically motivated their studies of the perception of human movement by asserting that successful social behavior depends upon it. But does it? Five psychophysical studies were performed to address this question. To the extent that social capabilities are related to visual sensitivity to human motion, observers with deficits in social function should show selective decrements in their visual sensitivity to human movement. Autism Spectrum Disorder (ASD) is characterized by impairments in social function and autistic traits extend into the general population. Thus, the magnitude of observers' autistic traits can serve as a measure of their social skills. The experiments reported here utilized a point-light target detection task in which observers reported whether a display contained coherent human, animal, or object movement. Overall, typical observers were consistently most sensitive to the presence of coherent human movement. In Experiments 1--3, both typically developing children and typically developed adults exhibited this pattern of performance. In contrast, observers with ASD and typical observers with increased autistic traits demonstrated equivalent sensitivity to human and object motion. Experiment 4 examined the specificity of this effect by testing relative sensitivity to animal motion. The results of this study indicated that typical adult observers were better able to detect the presence of coherent human motion relative to animal or object motion. Furthermore, autistic traits only correlated with detection of human motion. Experiment 5 tested whether a previously documented perceptual effect; namely, enhanced sensitivity to angry human motion, was related to social abilities. The results of this study indicated that enhanced detection of potentially threatening, angry, human movement decreased as the magnitude of an observer's autistic traits increased. Overall, the results of these studies support a tight coupling of laboratory studies of visual sensitivity to the presence of coherent human movement and social behavior outside of the laboratory. Furthermore, these studies illustrate the promise of measuring autistic traits along a continuum of typical and atypical observers to study social behavior and its relation to performance on psychophysical tasks.