Two groups of children with autistic-type behavior problems were compared to a group of normal children with respect to their autonomic response patterns observed during the performance of an attention-demanding task. Heart rate, blood pressure, and respiratory activity were measured during periods of rest and of task performance. Applying a quantitative model of the baroreflex, we were able to demonstrate qualitative differences among the groups with respect to their vagally controlled response patterns, whereas sympathetic responsiveness did not differ. In terms of our model, the groups with autistic-type behavior showed a decrease in central vagal tone during task performance, while vagal gain appeared to be unaffected or even increased. In contrast, the children in the control group showed the expected pattern of a decrease in vagal gain while vagal tone appeared to be increased. Implications of our findings are discussed in the light of Damasio's somatic marking hypothesis.