This study was aimed at evaluating acquisition of responding on microswitches and awareness of contingency with 3 adolescents who had profound multiple disabilities. Their favorite stimulation was used contingently and noncontingently on their responding on microswitches. Analysis showed that they acquired and maintained high responding frequencies only with contingent stimulation, indicating that such responding reflected an awareness of contingency rather than stimulation-related arousal and activity. Implications of the findings are discussed.