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,withcascading consequencesforbothsocialdevelopment and the lifelong impairments in social interaction that are a hallmark of autism spectrum disorders 8 . Here we show that two-year-olds withautismfailtoorienttowardspoint-lightdisplaysofbiological motion, and their viewing behaviour when watching these pointlight displays can be explained instead as a response to non-social, physicalcontingencies—physicalcontingenciesthataredisregarded by control children. This observation has far-reaching implications for understanding the altered neurodevelopmental trajectory of brain specialization in autism 9 . Preferentialattentiontobiologicalmotionisafundamentalmechanism facilitating adaptive interaction with other living beings. It is present throughout a wide range of species, from humans 10,11 to monkeys 12 to birds 13 . Developmentally, it can be found in newly hatched chicks 14 and in human infants as young as 2days old 1 . Recognitionofbiologicalmotionremainsintactinavarietyofforms, from degraded presentations, through varying states of occlusion, and in cases when information-bearing components are reduced to