Abnormal electrodermal reactivity to novel visual stimuli in autistic children.

Skin conductance responses and eye-fixation behavior to visual stimuli were measured in high-functioning autistic children, normal children, children with externalizing disorders, and children with internalizing disorders. Novelty, complexity, and subjective significance of the stimuli were manipulated. Autistic children were electrodermally hyporesponsive to novel stimuli. In all groups, manipulation of stimulus complexity only influenced fixation time. Manipulation of subjective significance influenced fixation time as well as skin conductance response in all groups. In the autistic group, adding subjective significance to a stimulus changed electrodermal nonresponders into responders, indicating that nonresponsiveness or hyporesponsiveness in autistic children does not imply a loss of (novel) stimulus detection, filtering, or orientation reaction capability, per se.