Influence of Nonmemorial Factors on Manifestation of Short-Sample Biases

in Choice and Successive Matching-To-Duration Tasks with Pigeons

Ronald Kelly, Marcia L. Spetch, and Douglas S. Grant

University of Alberta

The effects of procedural modifications of choice and successive matching tasks on retention of event duration (2- and 10-s presentations of light) was examined. In accord with prior results, retention testing revealed that accuracy on short- and long-sample trials declined symmetrically in standard successive matching but asymmetrically (i.e., markedly on long-sample trials, and very little on short-sample trials) in standard choice matching. Moreover, asymmetrical retention functions were also obtained in (a) a modified successive task in which all trials ended in reinforcement and (b) a modified choice task in which the penalty for incorrect responding was substantially reduced. It was concluded that pigeons code duration analogically in both standard choice and successive matching tasks, and that such coding is manifest in asymmetrical retention functions only in the absence of a response bias engendered by the standard successive procedure.