Toward an Account of Habituation Patterns in Young Children with Autism

Abstract

Habituation is a critical process in infant development that if improperly acquired, will result in inadequate environmental control over a child's behavior and could have important implications for future acquisition of emotional repertoires, language, and cognitive development. The current investigation was designed to examine whether children with autism demonstrate patterns of habituation to repeating auditory stimuli that differ from typically developing peers. In Experiment 1, three dyads consisting of a child with autism and a typically developing peer matched on age and gender were exposed to repeating pulsating tones of 500, 2000, and 12,000 Hz at a constant intensity of 60 dB while playing a computer game. Subsequently, the children were exposed to repeating 60 dB tones while being read to by the experimenter. In Experiment 2, an additional dyad was exposed to 500, 2000, and 8000 Hz tones at 70 dB during a game condition, and subsequently exposed to tones in both reading and no-activity conditions. The effects of repeated stimulus exposure on orienting response, auditory brainstem response, galvanic skin response, and operant response accuracy were measured to conduct within-subject, within-session, and within-dyad comparisons. Results suggest that compared to typically developing peers, some children with autism exhibit 1) reliably different patterns of OR decrement that presented either as overresponsiveness or perceptual inconstancy depending on the stimulus conditions, 2) greater operant performance reductions, and 3) in some stimulus conditions, significantly greater response variability as measured on both orienting response and operant performance. The implications of these findings are discussed, and recommendations for further investigation are outlined.