Development of Excitatory Backward Associations during the Establishment of Forward Associations in a Delayed Conditional Discrimination by Pigeons

The development of excitatory backward associations in pigeons was demonstrated in three experiments involving conditional discriminations with differential outcomes. In Phase 1 of all three experiments, correct comparison choicesfollowing one sample were followed-by-food, whereas correct comparison choices followingthe other sample were followedby-presentation-of-an-einpty feeder. In Phase 2, the food and no-food events that served as outcomes in Phase 1 replaced the samples. Whenthe associations tested in Phase 2 were consistent with the comparison-outcome associations developed in Phase 1, transfer performance was significantly better than when the Phase 2 associations were inconsistentwith the Phase 1 associations. In Experiment 1, an identity matching-to-sample task was used with red and green samples and red and green compari- sons. In Experiment 2, a symbolic matching task was used with shape samples and hue-conipari-- sons, and it was shown that the backward associations formed were between the trial outcome (food or no food) and the correct comparison. In Experiment 3, it was determined that the transfer effects observed in these experinients didnot dependon either the similarity of behaviordirected toward the samples in the training and test phases, or the similarity of food and no-food expec.. tancies generated by the samples in Phase 1 to food and no-food events presented as samples in Phase 2.