Testing can facilitate forgetting of tested items

Previous research has shown that taking a test facilitates memory retention on later retesting, although facilitation is stronger when retesting is delayed. On the basis of the finding that testing prevents later forgetting without affecting memory recovery, we investigated immediate effects of taking a test on retrievability of a tested item. In two experiments, forty participants recalled studied items, then performed a retest of the studied items (test condition) and a non-episodic-memory task (distractor condition), and immediately afterward re-recalled the items. The test condition elicited more item losses (i.e. forgetting) than the distractor condition, whereas there were no condition differences in the number of item gains (i.e. remembering) and recall clustering. These results suggest that taking a test on a target item facilitates forgetting of the very same item for a short interval of time, a possible reason for the late appearance of the testing effect.