SCHEDULE‐INDUCED POLYDIPSIA: ARE RESPONSE‐DEPENDENT SCHEDULES A LIMITING CONDITION? 1

Abstract

The collateral water intake of albino rats was measured when the inter‐pellet intervals in fixed‐ratio and fixed‐time schedules were equated. Fixed‐ratio and fixed‐time inter‐pellet intervals were equated by dividing the average fixed‐ratio session time of each subject by 150 (food pellets). The average inter‐pellet interval obtained then defined the subsequent fixed‐time schedule for each individual subject. Shifts to fixed‐time schedules followed the completion of each fixed‐ratio 20, 40, and 80 schedule. This procedure permitted an assessment of the extent to which excessive collateral drinking was associated with inter‐pellet interval length or adventitious food reinforcement. For both the fixed‐ratio and fixed‐time schedules, drinking progressively increased as a function of increasing the duration of the inter‐pellet interval and was a post‐pellet event under the control of variables other than adventitious food reinforcement.