OVERT “MEDIATING” BEHAVIOR DURING TEMPORALLY SPACED RESPONDING1
A rat was trained on a schedule that programmed reinforcements only when a minimum waiting time between successive responses was exceeded (DRL schedule). It was observed to fill much of the pause between lever presses with a stereotyped behavioral chain: it would take its tail in its mouth and nibble it. This behavior was shown to be functionally related to the efficiency with which the subject spaced its responses. It is thought to have served as mediating behavior, providing discriminating stimuli for appropriate lever presses.