JOURNAL OF THE EXPERIMENTAL ANALYSIS OF BEHAVIOR THREE-CONFIGURATION MATCHING-TO-SAMPLE IN THE PIGEON'

Pigeons were trained on a zero-delay matching-to-sample procedure during which only three of the four possible stimulus configurations were presented. Subsequently, all birds were exposed to all four configurations as a transfer test. A high degree of negative transfer from the three training configurations was obtained in Experiment 1. The re-sults of Experiment 2 indicated that three-configuration training produced differential position-preference effects. During the transfer test, responding after one sample stimulus was apparently based on position, while responding after the other sample was based on color. In the usual two-stimulus, three-key match-ing-to-sample experiment (Cumming and Ber-ryman, 1961) there are four possible stimulus configurations that can be presented to the subject on any particular trial. For example, when red (R) and green (G) are used as stimuli, the four configurations on the thre