Appetitive contextual conditioning in rats: preliminary studies about the role of inter-sessions interval

Abstract

In three experiments in which the intersession interval was manipulated, there was no evidence that this variable would affect appetitive contextual conditioning in rats. The importance of this manipulation stems from a prediction of scalar. expectancy theory according to which contextual conditioning depends on a comparison of the reinforcer expectancy outside the training context with the expectancy in the training context. This theory moreover suggests that the magnitude of the reinforcer expectancy outside the training context is an inverse function of the length of the intersession interval. This effect was not found when the interval was manipulated by varying the number of sessions per day (Experiment 1) or more directly by varying the interval between sessions itself (Experiments 2 and 3). The experimens also involved a direct measurement of contextual conditioning by the responses elicited in anticipation of the reinforcer (Experiments 1 and 2), or a transfer test involving autoshaping acquisition after contextual conditioning (Experiment 3). These results give also no support for other theories based on similar comparator mechanisms, as well as the Rescorla-Wagner model based on competition for associative strength between the static elements collectively described as the context