The primary objective of this work will first to characterize in typical childhood, visual exploratory behavior and pupillary response associated with salience of human social stimuli (faces and body movements), and then to evaluate these markers in children with autism.

The second objective of this work will be to achieve in a population of children with autism a longitudinal evaluation of these markers during development and therapeutics.

Patients with autism have significant social difficulties and communication alterations. It has been shown in these patients difficulties to understand some clues indispensable to social relations, for example, faces and their emotions and motion of human bodies. The faces and human movements are an important source of information helping to interact with others. Understanding the intentions of the others through facial expressions and gestures can help them to adapt their behavior and their interactions. While in healthy subjects, faces and human movements receive special attention, autistic patients seem to pay less attention to this kind of social stimuli. It has already been shown that children and healthy adults spend more time looking at faces and human movements (relative to objects), whereas the opposite behavior is observed in patients with autism. Studying gaze behavior seems to be essential for progress in the understanding of autism pathology. Eye-tracking systems allow to measure precisely what a subject looks on a picture. Moreover, eye-tracking systems permit the measurement of the pupil size which variations are correlated with cognitive processes. The objective of this study is to analyze the ocular behavior (ocular scan path and pupil diameter) of young patients with autism when viewing faces and human movements and to compare these measurements with those of chronologically age-matched healthy children. This work will identify attentional problems concerning exploration of human faces and movements that can be related to their social difficulties. These disorders should be manifested by an atypical ocular scan path and by changes in pupil variation in response to face and human motion. Then to follow the evolution of these indices will allow to evaluate the effect of therapies. These results will highlight new data essential to understanding disorders of social relations and to better adapt rehabilitative strategies.

Inclusion Criteria:

• For autistic children, diagnosis of autism spectrum disorders according to DSM IV-TR and ADI / ADOS criteria ; normal or corrected vision; no nervous system disease
• For healthy children, normal schooling and normal or corrected vision
• For all, parental consents

Exclusion Criteria:

• psychotropic treatment

Autistic children from the University Hospital of Tours Healthy children from the normal population