efficiency, the animals need to sample both options to develop a sense of the yield of each alternative and to learn when and how often it is advantageous to switch away the more profitable option to the one that normally leads to a poorer revenue of reward. In fact, in the particular version of the task used by Kennerley and colleagues (2006), rewards are obtained at the highest rate if the fraction of responses of a given type is equal to, or “matches”, the fraction of total rewards that are earned by making that response.
