Introduction to Special Issue on Incentive Relativity

Abstract

In 1996, Charles Flaherty opened the prologue of his book Incentive Relativity with these words: “We compare. Many of the pleasures and irritations of life are related to the match between an event and our expectancies. We compare meals, composers, presidents, books, performances, salaries, and many other events that have some interest or value” (Flaherty, 1996, p. 1). The capacity of organisms to acquire reward expectations based on prior experience and to contrast them with their immediate reality is referred as incentive relativity. Incentive relativity implies not only a mechanism for processing information, but also an emotional component resulting from such comparison. Our passions, feelings, and emotions are often based on a comparison of relative outcomes, and, when such comparison results in what is appraised as a significant loss, a state of stress, anxiety, aggression, depression, and substance abuse can follow, among other psychopathological states. Almost two decades after Flaherty’s words, the analysis of incentive relativity effects continues to engage specialists in behavior, cognition, clinical psychology, pharmacology, and neuroscience. Nonhuman animals also compare incentives and exhibit affective responses to the outcome of such comparisons. This characteristic allows researchers coming from different disciplines to approach the scientific study of incentive relativity using animal models of human behavior. We now know a large variety of paradoxical learning effects based on the presentation of different reward values (contrast effects) or reward contingencies (partial reinforcement and extinction). The behavioral, environmental, hormonal, pharmacological, neurobiological, and genetic characterizations of these phenomena are part of a field of basic research of great tradition and, simultaneously, of current importance given their clinical and applied implications. In this special issue, leading experts review incentive relativity from a multidisciplinary perspective. Research on different approaches is presented, including empirical articles and critical reviews. A key focus of the present special issue is to highlight the contribution of animal research to extend our knowledge of some basic principles of learning and their emotional correlates in a variety of organisms, including humans. The first paper by Bueno, Judice-Daher, and Deliberato (pp. 410-419) investigates a phenomenon related to reward loss: the reinforcement omission effect. Bueno and co-authors aim to clarify the relationship between reinforcement magnitude and the reinforcement omission effect manipulating the magnitude linked to discriminative stimuli in a partial reinforcement fixed interval schedule. The empirical and theoretical implications of the results are discussed.