VALUE TRANSFER IN A SIMULTANEOUS DISCRIMINATION BY PIGEONS - THE VALUE OF THE S+ IS NOT SPECIFIC TO THE SIMULTANEOUS DISCRIMINATION CONTEXT

During simultaneous discrimination training, there is evidence that so me of the value of the S' transfers to the S-. When the value of the S + is altered outside the context of the simultaneous discrimination, t wo very different predictions are made concerning its effect on its S- , depending on whether one views the S+ as an occasion setter or as a stimulus capable of transferring value. In four experiments, pigeons w ere trained with two similar simultaneous discriminations, A(+)B(-) an d C+D-, and two single-stimulus trial types, A and C, (in which A alwa ys had greater nominal value than C). According to value transfer theo ry, on test trials, B should always be preferred over D, because B and D should be affected by the net values of A and C, respectively. Acco rding to an occasion setting account, however, D should be preferred o ver B because the presence of D signals a higher probability of reinfo rcement for responding to C than when C is alone, and/or the presence of B signals a lower probability of reinforcement for responding to A than when A is alone. In all four experiments, the pigeons preferred B over D, a result consistent with value transfer theory. Thus, an S- c an acquire value from an S+ even when that value is conditioned in a ' 'context'' different from that of the simultaneous discrimination.