Risk-Sensitivity in Rats (Rattus norvegicus): Effect of the magnitude and probability of reinforcement

Abstract

Using a free-choice experimental task with rats (Rattus norvegicus), the effect of the magnitude and the probability of reinforcement was studied. Both variables were manipulated in two different alternatives of response, being equal the quantity of reinforcer on each alternative at the end of the experimental session. Initially, the rats were sequentially trained on two alternatives of response (forced-choice): 1) to get with high probability of reinforcement less magnitude of reinforcer (risk aversion) and 2) to get with low probability of reinforcement more quantity of reinforcer (risk prone). After the training, both alternatives of response were simultaneously presented (free-choice). In general, rats were risk averse. Nevertheless, a fine-grain analysis shows an interaction effect between both variables considered. This effect conveys about the possible risk propensity of the rats when these variables are combined into the same experimental preparation.