From Actions to Faces : Studies of Social Perception in Typical and Atypical Development

Sammanfattning: This thesis consists of three eye-tracking studies of social perception in children. Study I and Study II investigated action perception in typically developing infants and preschoolers with Autism Spectrum Disorder (ASD), respectively. Study III investigated face perception in children with ASD.Do infants come to understand others’ actions by a Mirror Neuron System (MNS) that maps others’ actions onto motor plans for similar actions? In Study I, we measured the eye movements while participants observed video clips of an actor's hand placing toys into a bucket. Adults and twelve-month-old infants looked at the bucket before the hand reached it, predicting the goal of the action. This predictive performance was linked to seeing a hand-object interaction. Six-month-olds failed to predict the goal of the action. The development in prediction skills coincides with the age at which infants learn to perform the action themselves. This supports the view that the MNS forms the basis of important social competences such as predicting others' actions.According to the MNS theory of ASD, a failure to map others’ actions onto motor plans for similar actions underlies the social symptoms defining the disorder. In Study II, children with ASD as well as typically developing children and adults were shown the same stimuli as used in Study I. At odds with the theory, all groups used strikingly similar predictive eye movements in action observation. Gaze was reactive in a self-propelled condition, suggesting that prediction is linked to seeing a hand-object interaction. This study does not support the view that ASD is characterized by a global dysfunction in the MNS.Face processing is another core social competence, and research has suggested that many individuals with ASD have face processing impairments. In Study III, we showed faces to young children with ASD and related their looking performance to their behavioural symptoms. Our findings suggest that the socio-communicative information transmitted from faces is processed in a piecemeal fashion in young children with ASD. Much of the variability in face scanning could be explained by individual differences in socio-communicative skills.