Simultaneous Discrimination Learning in Pigeons: Value of S - Affects the Relative Value of its Associated S+

Abstract

In a simple simultaneous discrimination involving a positive stimulus (S+) and a negative stimulus (S−), it has been hypothesized that positive value can transfer from the S+ to the S− (thus increasing the relative value of the S−) and also that negative value can transfer from the S− to the S+ (thus diminishing the relative value of the S+ Fersen, Wynne, Delius, & Staddon, 1991). Evidence for positive value transfer has been reported in pigeons (e.g. Zentall & Sherburne, 1994). The purpose of the present experiments was to determine, in a simultaneous discrimination, whether the − diminishes the value of the S+ or the Sis contrasted with the S+ (thus enhancing the value of the S+). In two experiments, we found evidence for contrast, rather than value transfer, attributable to simultaneous discrimination training. Thus, not only does the S+ appear to enhance the value of the S−, but the S− appears to enhance rather than reduce the value of the S+.