A series of experiments was carried out to evaluate the notion that rats given a sequence of massed daily trials on the radial maze reset working memory at the end of each trial by deleting its contents. Although curves presented by D. S. Olton [Scientific American, 1977, 236, 82-98: In S. H. Hulse, H. Fowler, & W. K. Honig (Eds.), Cognitive processes in animal behavior, 1978, Hillsdale, N.J.: Erlbaum] show that rats return to errorless performance at the beginning of each trial after the first, the fact that accuracy falls less rapidly over choices on Trial 1 than on subsequent trials suggests a proactive inhibition (PI) effect. In Experiment 1, Olton’s findings were replicated, and a PI effect was observed on Days 1-2 of testing. On Days 3-5, overall accuracy improved significantly and was associated with the development of a strong tendency for rats to enter adjacent alleys, which became particularly marked on the final trials of a day’s testing. In order to prevent rats from achieving accurate performance by using an adjacent alleys pattern, a procedure was used in Experiment 2 which involved initial forced random choices followed by a retention test consisting of free choices. Repeated daily trials with this procedure yielded a significant PI effect, which was more marked at a 60-sec delay than at a 0-sec delay. Experiments 3 and 4 showed this PI effect to be robust and resistant to manipulations designed to produce release from PI. Both the PI effect and a strong tendency found in Experiment 1 for animals to avoid on the initial choices of Trial n those alleys most recently entered on Trial n - 1 argue that rats do not reset working memory between trials.
NOTICE: this is the author’s version of a work that was accepted for publication in Learning and Motivation. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Learning and Motivation, Volume 12, Issue 3, (August 1981), DOI: http://dx.doi.org/10.1016/0023-9690(81)90009-6