Stimulus control by part of a complex SΔ

Abstract

Pigeons were trained to peck at each of four stimuli projected onto a response key. Subsequently, responding was reinforced in the presence of a compound stimulus composed of two of these stimuli (red background with horizontal white bar) and extinguished in the presence of a compound stimulus composed of the other two stimuli (green background with vertical white bar). In an extinction session following this discrimination training, each of the four stimuli were again presented separately. Differential responding was found to the components associated with reinforcement and to the components associated with nonreinforcement. These results replicate earlier demonstrations of selective control by part of a complex SD and add a demonstration of selective control by part of a complex SΔ.