Failure to demonstrate schedule-induced hyperphagia with a fixed time 1-minute water delivery schedule

The reduction of an animal's body weight to 80% of its Free Feeding Weight (FFW) is purported to be an important factor in the generation of schedule-induced behaviour. However, the importance of this factor in schedule-induced hyperphagia is unclear. Experimental studies in schedule-induced hyperphagia reported conflicting results. The aim of the present series of five experiments was to clarify the several conflicting factors in the generation of schedule-induced hyperphagia. Rats reduced to 80% FFW by water restriction and on a Fixed Time (FT) 1-min water delivery schedule showed that body weight reduction, water delivery schedule, size and distance of pellets, and order of schedule presentation were not important factors in the generation of schedule-induced hyperphagia. The failure of the present series of experiments to demonstrate schedule-induced hyperphagia suggests that this behaviour may be a specific class of schedule-induced behaviour that can only be demonstrated under the Bellingham, Wayner and Barone experimental paradigm.