Competition and suppression as forgetting mechanisms in episodic recall

Both the storage of new episodes and the retrieval of already stored episodes can cause interferences in episodic recall. In the past 25 years these interferences have often been explained by means of the concept of strength-dependent competition. According to this concept episodes associated to a common cue - for instance, having been observed in the same spatial-temporal context - compete for access to conscious recall when that cue is presented. If new episodes are stored or already stored episodes are strengthened through their retrieval, competition is increased and forgetting of episodes may occur. The results of experiments from the past five years suggest that this theory is inadequate and interferences are not caused by strength-dependent competition. Rather the data indicate that some types of interference are the result of a non-strength-dependent competition mechanism, whereas others are the result of a suppression mechanism. Some practical consequences of these findings for close questioning situations, like interviews of witnesses for legal evidence, are discussed.