"Suboptimal choice": The incentive salience of the stimuli and the role of conditional inhibition

Abstract

In the “suboptimal choice” procedure, pigeons, but not rats, systematically choose an alternative associated with stimuli that indicate the presence or absence of a reward and with a smaller probability of reinforcement, over another option associated with noninformative stimuli, and a higher probability of reinforcement. To explain these opposite preferences, it has been proposed that rats and pigeons have a differential sensitivity to the conditioned inhibition that emerges from the stimulus that predicts non-reinforcement: While it does not have an impact in pigeons, it strongly influences rats’ preferences. Alternatively, it was recently proposed that there is not a fundamental difference in the behavior of rats and pigeons, but that the procedure employed to evaluate each of these species has generated the difference; in particular, it was proposed that both species prefer the discriminative alternative when the discriminative stimuli have incentive salience. In this paper we review the theoretical assumptions underlying these proposals because the evidence regarding the incentive salience of the stimuli has found contradictory results. Finally, future theoretical suggestions are made to resolve these differences in results in the theoretical proposals to explain the differences between species in the "suboptimal choice" procedure.