Spaced food but not electrical brain stimulation induces polydipsia and air licking.

An attempt was made to induce polydipsia in rats whose lever pressing was reinforced with food pellets or electrical brain stimulation. Nine food-deprived, water-sated rats drank water excessively during sessions in which food pellets were delivered. When brain stimulation was substituted for food, drinking immediately ceased. Delivering brain stimulation according to a variety of schedules, pairing brain stimulation with food reinforcement, and substituting an air stream for water, each failed to produce polydipsic licking. These results show that polydipsia is not induced by all reinforcers.