Dissociation of short-term forgetting from the passage of time

In many theories, forgetting is closely linked to the passage of time. In the present experiments, recall in a short-term memory task was less accurate when the retention interval included a difficult arithmetic addition task, compared with an easy task. In a novel condition, the interfering task was switched from hard to easy partway through the retention interval. Recall accuracy at long retention intervals recovered from the level consistent with the hard interfering task to a more accurate level consistent with an easy interfering task. Such recovery is not in agreement with theories that link forgetting to the passage of time, such as trace decay. The reversed forgetting functions are more consistent with an account in which different levels of nonspecific retroactive interference in the retention interval just before the time of retrieval influence different levels of performance accuracy. With the uncoupling of interference levels from time, forgetting is dissociated from the passage of time.