PRIMACY, RECENCY, AND THE VONRESTORFF EFFECT IN RATS NONSPATIAL RECOGNITION MEMORY

In 2 experiments, nonspatial memory was investigated. Hungry rats obtained food in a Y maze with a continuous nonmatching-to-sample procedure, which used objects placed in goalboxes as stimuli. Rats visited 5 goalboxes, each containing 1 object. After a retention interval, the rats were presented with a choice between a goalbox identical to one in the series and a novel goalbox. Of 11 subjects, 8 displayed both primacy and recency effects, 1 displayed only recency, and 2 displayed no systematic serial position effects. Subsequently, on some sessions, the 3rd goalbox in the list was accompanied by a salient stimulus. In 8 of the 11 subjects, this procedure led to enhanced recall of the goalbox that was associated with the stimulus change.