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ON THE NATURE OF DEFICITS IN EMPATHY IN AUTISM

Geraldine Dawson, Andrew Meltzoff, Julie Rinaldi, and Julie Osterling

Psychology Department, Box 351525 University of Washington, Seattle, Washington 911195

A cluster of impairments characterizes young autistic children. This cluster includes of a failure to attend to other people and impairments in imitation, joint attention, and empathy. Recent studies have shed light on the neuropsychological basis of autism, demonstrating impairments on prefrontal tasks (McEvoy et al., 1993). More recently, studies of young autistic children have discovered deficits on medial temporal lobe tasks (Barth & Fein, m press). The latter findings have led some investigators to suggest that frontal lobe impairments in autism may be caused by “downstream” effects of medial temporal lobe dysfunction. Autopsy studies in autism have consistently found neuronal abnormalities in the medial temporal lobe, particularly the hippocampus and amygdala (Bauman & Kemper, 1985, 1988). Moreover, Bachevaher (1991, 1994) has demonstrated that nonhuman primates with early lesions of the hippocampus and amygdala exhibit social impairments similar to the autistic syndrome. Dawson, Meltzoff, Osterling & Rinaldi (1995) have discovered that young autistic children’s performance on a medial temporal lobe task (delayed non-matching to sample) is predictive of the severity of early autistic symptoms, including impairments in social orienting, motor imitation, and joint attention.

In the present study, we sought to understand autistic children’s impairment in the area of empathy. First, are deficits in empathy related to autistic children’s difficulties in performing medial temporal lobe tasks? The ability to recognize emotions has been linked to the amygdala based on tests conducted with an adult with a bilateral lesion of the amygdala (Adolphs et al., 1994). Second, are deficits in empathy related to autistic children’s difficulties in imitating others ? It has been argued that imitation may provide a bridge that allows the emotional state of another to be transmitted to another (Meltzoff & Gopnik, 1993; Dawson & Lewy, 1989).

Participants were 20 children with autism, 18 children with Down syndrome, and 20 normally- developing children who were matched in terms of receptive language ability (M’s on the Preschool Language Scale were 28.1, 30.3, 31.8 mos.. , respectively). Clinical groups were also matched on CA (M’s were 64.6 and 65.3 mos.). The paradtgm used to assess empathy was one used by Sigman et al. (1992). The child was seated at a table across from the experimenter who showed the child how to use a wooden pounding toy and hammer. During this demonstration, the experimenter pretended to hurt herself and displayed facial and vocal expressions of distress. Attention, play behavior, and degree of concern (affect and comforting behavior) were coded by naive reliable coders. The medial temporal lobe task was the delayed non-matching to sample task (DNMS) which assesses visual recognition memory. DNMS. performance is impaired in monkeys following lesions of the medial temporal lobe and in amnesic patients. The frontal lobe task was the delayed response task which requires working memory and inhibition and has been firmly linked to prefrontal cortex. The imitation battery consisted of 15 items, 10 immediate imitation tasks and 5 deferred imitation tasks. A range of imitation tasks was used, including gestures that the subjects could or could not see themselves perform, and novel and familiar acts.

Results showed that, in response to the experimenter’s distress, autistic children spent less time looking at the experimenter (p c .OOOl), spent more time looking at (p < .005) and playing with the toy (p < .0002), and showed less concern (p < .Ol). Only for autistic children, medial temporal lobe task performance was found to be predictive of empathic responding in terms of both the degree of concern they displayed (p < .05) and the percentage of time they played with the toy (p < .05). Empathicrespondmg was not related to performance on the frontal task. Furthermore, only for autistic children, imitation ability was found to be predictive of degree of concern (p < .05) and of the percentage of time spent looking at the experimenter (p < .05). These results provide further support for the role of the medial temporal lobe in the early social deficits found in autism, and highlight the role of imitation in the development of empathy.