Primary and Secondary Motivational Properties of a Light Stimulus

Abstract

Rats were trained on a continuous reward schedule (CRF) in a 2-bar test box with or without light contingency associated with food reward. During extinction trials with the light contingency presented on CRF, the light contingency was shown to facilitate extinction on the basis of response totals (energizing effect) and percentage of responses on the reward bar (directional effect). For these extinction trials, no evidence was obtained for secondary reinforcing (Sr) properties of the light contingency. However, a second experiment found a strong Sr energizing effect when the light contingency was presented on a FR-5 or FR-10 schedule during extinction trials. These energizing effects were also obtained for rats trained without the light contingency, but to a lesser degree than for rats trained with the light contingency. Presentation of the light contingency on a FR schedule during extinction trials also resulted in a strong directional effect for all groups, regardless of the training condition. A moderately durable energizing effect of Sr was obtained which was an increasing function of partial periodic Sr during extinction trials.