The stay/switch model of concurrent choice.

This experiment compared descriptions of concurrent choice by the stay/switch model, which says choice is a function of the reinforcers obtained for staying at and for switching from each alternative, and the generalized matching law, which says choice is a function of the total reinforcers obtained at each alternative. For the stay/switch model two schedules operate when at each alternative. One arranges reinforcers for staying there and the other arranges reinforcers for switching from there. Rats were exposed to eight or nine conditions that differed in the arrangement of the values of the stay and switch schedules. The generalized matching law described preferences when arrangements were similar to those found when using two concurrently running interval schedules. It did not, however, describe all preferences when using different arrangements. The stay/switch model described all preferences in one analysis. In addition, comparisons of selected conditions indicated that changing the ratio of obtained reinforcers was neither necessary nor sufficient for changing preference as measured by response ratios. Taken together these results provide support for the stay/switch model as a viable alternative to the generalized matching law and that the critical independent variable is allocation of stay and switch reinforcers.