The aim of this study was to determine whether displays of negative emotions are more aversive to young children with autism than displays of neutral emotions. The attention, behavioral reactions, facial affect, and cardiac responses of 22 autistic and 22 mentally retarded 3-5-year-old children were compared when an experimenter pretended to hurt herself and showed strong distress in contrast to when the experimenter pretended to hurt herself but showed only neutral affect. The children in both diagnostic groups looked more at the experimenter and appeared more interested and concerned when she displayed strong distress than when she showed neutral affect. The heart rate of the mentally retarded children decreased during the distress condition relative to a baseline condition, but the heart rate of the children with autism did not change across conditions. In summary, the children with autism gave no evidence of being overly aroused by or avoiding the distressed experimenter.