Memory in the pigeon: Proactive inhibition in a delayed matching task

Abstract

Proactive inhibition in a pigeon was studied, using a modified delayed matching-to-sample task. Proactive inhibition was defined as disruption in matching performance produced by the presentation of a stimulus prior to the sample stimulus (relative to control trials without prior stimulus presentation). In Experiment I, with a prior stimulus which was not presented as one of the comparison stimuli, temporary disruption in matching performance was found with a 5-sec delay between sample and comparison stimuli but not with a 0-sec delay. In Experiment II, with a prior stimulus which was later presented as the incorrect comparison stimulus, long-lasting disruption was found with a 5-sec delay, but again not with a 0-sec delay. Experiment III demonstrated a direct relation between the magnitude of proactive inhibition and length of the delay. These results offer some support for an interference theory of forgetting, but also suggest that it may not be the identity of the two stimuli but, rather, the order of the two stimuli which is lost.