Abstract

Inhibitory processes are widely acknowledged to be critical in the brain and in cognition (e.g., sensation, attention, motor control)—yet, there has been, and is, a reluctance to postulate the role of inhibition in memory. Some have argued, however, that inhibition is a critical and necessary component of the human memory system. Information becomes irrelevant and outdated, and without some means of forgetting or setting aside such information, accessing new and relevant information would become increasingly difficult. A context in which inhibition appears to be particularly important is that of retrieval. In searching for an item in memory, other items that are related, but incorrect, can vie for access. Inhibition functions to decrease the accessibility of such interfering items, thereby facilitating access to the target item. This inhibition may explain a rather unintuitive empirical observation—that retrieving some items from memory causes the forgetting of other related items in memory, a phenomenon known as retrieval-induced forgetting. Although inhibition may seem like a reasonable explanation of this phenomenon, retrieval-induced forgetting can also be explained by other factors, such as associative interference. The experiments reported here were designed to test three assumptions of the inhibitory account of retrieval-induced forgetting. First, that because inhibition resolves competition, items that fail to compete for retrieval should not be forgotten. Second, that it is the attempt to retrieve, and not the retrieval per se, that causes forgetting. And third, that although inhibited items may become less accessible, they should retain their general, or overall, strength in memory. Taken together, the results support and refine the inhibitory account of retrieval-induced forgetting—and, more generally, offer additional evidence that inhibition plays an active and adaptive role in human memory.