THE INFLUENCE OF AN IRRELEVANT STIMULUS ON 2 DISCRIMINATIONS

In 3 experiments, the effect of adding an irrelevant stimulus to a discrimination was examined. In Experiment 1, a group of pigeons received autoshaping with an A+ A.Bo discrimination in which 1 stimulus signaled food, A+, and a simultaneous compound of A with another stimulus, B, signaled the absence of food, ABo. A second group received similar training, except that a third stimulus, C, was present in both types of trials, AC+ ABCo. The A+ ABo discrimination was acquired more readily than the AC+ ABCo discrimination. Experiments 2 and 3 used a negative-patterning design, A+ ABo B+. In both experiments, this problem was mastered more readily than when an irrelevant stimulus was used to create an AC+ ABCo BC+ discrimination. The results fail to confirm predictions derived from elemental theories of conditioning.