ASYMMETRICAL INTERACTIONS BETWEEN THIRST AND HUNGER IN PAVLOVIAN-INSTRUMENTAL TRANSFER

Pavlovian-instrumental transfer experiments have demonstrated that a s timulus paired with a sucrose solution under hunger will increase inst rumental performance under thirst relative to a stimulus previously pa ired with food pellets. In Experiment 1 it was demonstrated that this difference is, in part, produced by suppression induced by the pellet stimulus, which, it was found, acted to reduce instrumental performanc e under thirst. In Experiment 2, the reverse shift was examined, compa ring the effects of stimuli paired with either a saline solution or a sucrose solution under thirst on instrumental performance under hunger . Although the sucrose stimulus was found to elevate performance when hungry, the saline stimulus was found to be without effect. This asymm etry in the interaction between hunger and thirst is discussed in term s of the way motivational states control the interaction between senso ry and affective components of the reinforcer.