Two-year-olds with autism orient to non-social contingencies rather than biological motion

Typically developing human infants preferentially attend to biological motion within the first days of life(1). This ability is highly conserved across species(2,3) and is believed to be critical for filial attachment and for detection of predators(4). The neural underpinnings of biological motion perception are overlapping with brain regions involved in perception of basic social signals such as facial expression and gaze direction(5), and preferential attention to biological motion is seen as a precursor to the capacity for attributing intentions to others(6). However, in a serendipitous observation(7), we recently found that an infant with autism failed to recognize point-light displays of biological motion, but was instead highly sensitive to the presence of a non-social, physical contingency that occurred within the stimuli by chance. This observation raised the possibility that perception of biological motion may be altered in children with autism from a very early age, with cascading consequences for both social development and the lifelong impairments in social interaction that are a hallmark of autism spectrum disorders(8). Here we show that two-year-olds with autism fail to orient towards point-light displays of biological motion, and their viewing behaviour when watching these point-light displays can be explained instead as a response to non-social, physical contingencies-physical contingencies that are disregarded by control children. This observation has far-reaching implications for understanding the altered neurodevelopmental trajectory of brain specialization in autism(9).