The motivational properties of schedule-induced polydipsia.

Schedule-induced polydipsia occurred during initial magazine training to Noyes pellets (45 mg), disappeared when lever-pressing was acquired on a continuous reinforcement schedule (CRF), and reappeared when the food contingency was changed to a 1-min variable interval schedule (VI 1 min). Polydipsia also developed under a VI 1 min food schedule when water was concurrently available on various fixed ratios (FR), rather than being freely available. The level of the polydipsia and its motivating properties allow it to be classified as a form of adjunctive behavior.