Associative and occasion-setting properties of contextual cues in flavor-nutrient learning in rats

This article studied the role of contextual cues, present at the time flavor conditioning occurs, on intake behavior in rats. In three experiments animals were given flavor-sucrose pairings in one distinctive context (Context A) whereas the flavor was presented unreinforced in an alternative context (Context B). Experiments 1 and 2 used a simple Pavlovian discrimination procedure (A: X+, B: X-) and tested consumption of flavor X in each context. Consumption of the flavor was higher in Context A than in Context B. In Experiment 2 rats were given a treatment (exposure to water in the context) designed to extinguish associations between the context and the reinforcer. This procedure did not affect the ability of the context to control intake of flavor X. Experiment 3 used a biconditional discrimination procedure (A: X+, Y-: B: X-, Y+; where X and Y were different flavors) in which no single context or flavor predicted reinforcement. The rats learned this discrimination, consuming more of each flavor in the context in which it had previously been reinforced. The results are interpreted in terms both of the effects of direct associations between context and events presented in them, and in terms of the modulatory or occasion-setting properties of the context. (C) 2012 Elsevier Ltd. All rights reserved.