In Experiment I rats deprived of either food or water were given free access to food or water respectively, and their behaviour was observed during self-imposed pauses in feeding or drinking. In Experiment II food or water were delivered according to fixed-time 30-s and fixed-time 60-s schedules, and the behaviour of the rats was observed during the interreinforcement intervals imposed by these schedules. In both experiments the temporal pattern of those activities that occurred during pauses in eating differed from the pattern of activities occurring during pauses in drinking; and with both food and water the temporal pattern of activities during self-imposed pauses in consummatory behaviour in Experiment I proved a good predictor of the pattern of activities during schedule-imposed interreinforcement intervals in Experiment II. This suggests that intermittent schedules permit the occurrence of those activities that are normally closely associated with the consummatory behaviour in question. In Experiment II certain activities that occurred towards the end of the interreinforcement interval were found to be enhanced relative to baseline level, but there was no enhancement of activities occurring near the beginning of the interval. This is contrary to Staddon's (1977) account of schedule-induced behaviour, and suggests that schedule-induction is not as common as has sometimes been supposed.
Quasi-periodic response solutions in forced reversible systems with Liouvillean frequencies
