The assessment of the effects of varying interpellet intervals on schedule induced polydipsia using mass-food and no-food controls

Since Falk's original demonstration of schedule-induced polydipsia (SIP), various studies have been conducted on this phenomenon. One area of interest has been the effects of varying the interpellet interval (IPI) length on absolute water consumption. Studies have generally reported a bitonic function of SIP with increasing IPIs. Such a conclusion, however, can be made only if SIP is clearly measured and defined. It has been suggested that controls be used to determine that SIP is in fact induced under each of the schedule conditions. The present study measured absolute water intake in food-deprived rats on a number of intermittent fixed-time (FT) schedules and compared the resulting SIP to consumption under mass-food and no-food control conditions. Subjects drank more under all FT conditions than under the two controls, indicating that SIP was induced at each schedule value. Further, when consumption under the FT conditions was analyzed in relation to its controls, consumption still displayed a bitonic function with changes in the IPI.Chairman: Anthony Riley.