Strategies of Simultaneous Discrimination Learning in the Pigeon

Abstract

In Experiment I pigeons were trained on a simultaneous discrimination between red and orange. After they had overcome their position habits and mastered the problem they were presented on occasional test trials with two red or with two orange stimuli. On those test trials when both stimuli were positives the birds tended to peck always to one key; this key was the preferred key during the position habit phase of acquisition. On trials with two negative stimuli the birds chose the other key. These results suggest that the pigeons use the presence of the S− on their preferred side as a cue for pecking to the other side. Experiment II investigated the role of the S+. Transfer tests involving the introduction of a neutral stimulus suggested that pigeons vary in the extent to which they rely upon the S+. Some birds showed no preference for the S+ over the neutral stimulus. However, when required to learn a discrimination between the old S+ and the neutral stimulus, birds given the old S+ as the positive learned more rapidly than those given the neutral stimulus as the positive.