Intentional Forgetting: The Role of Retrieval in Encoding

Abstract

Intentional remembering and intentional forgetting are adaptive processes that permit us to exert control over the contents of our memories. These abilities ensure that memory preserves the most goal-relevant information, and that goal-irrelevant information is discarded. Often studied in the literature using the item-method directed forgetting paradigm, research continues to debate the cognitive mechanisms that individuals use to intentionally remember and forget information. In this paradigm, during the study phase each presented item receives its own instructional cue—either to-be-forgotten (F) or to-be-remembered (R). The typical finding during the test phase is that memory is poorer for F items than for R items—the directed forgetting effect. In this dissertation, in Chapter 2, I tested the assumptions of a prominent and longstanding account of the directed forgetting effect: the selective rehearsal account. To do so, I manipulated the time available for rehearsal and time-based decay. Four experiments investigated the influence of instructional cue durations of 1, 5, and 10 seconds. Experiments 1a and 1b, with the order of cue durations randomized, showed no effect of cue duration on recognition of either R or F single words. Experiment 2, using unrelated word pairs, again showed no effect of cue duration, here on associative recognition. Experiments 3 and 4 blocked cue duration and showed enhanced recognition of both R and F single words and word pairs with increasing cue duration. To explain this set of findings, I suggested that better memory for R items than for F items across cue duration depends on (1) a rapid retrieval check engaged for R items only and (2) a rapid removal process implemented for F items only. Additionally, any post-cue rehearsal is carried out only when cue duration is predictable and is equally likely for F items and R items. In Chapter 3, I set out to test this rapid retrieval check mechanism by inducing an act of retrieval for F items. I predicted that if a rapid retrieval check of R items drives the directed forgetting effect, then inducing such a retrieval check mechanism for F items should reduce the magnitude of the directed forgetting effect. Experiment 5 demonstrated that simply repeating an F item in the encoding list did not force the retrieval of that item. However, in Experiment 6, incorporating a button press for the participant to indicate noticing the repetition of an item revealed that, for items where this repetition was noticed, the directed forgetting effect was eliminated. Experiment 7 induced an act of retrieval using an immediate recognition task following the R/F cue presentation. Results indicated that a retrieval check was successfully induced for F items where the target on the recognition task matched the preceding item, eliminating the directed forgetting effect and confirming the critical role of retrieval in item-method directed forgetting. Experiment 8 replicated these findings while also demonstrating that the removal of F items from working memory did not depend on an active inhibitory mechanism, framing the retrieval-based explanation as a non-inhibitory account of intentional forgetting at encoding. Ultimately, this dissertation provides a novel account of item-method directed forgetting in the form of a selective retrieval account. The account emphasizes the pivotal contribution of a rapid retrieval check mechanism applied only to R items during encoding being primarily responsible for the directed forgetting effect. This new theoretical perspective opens avenues for future research on intentional forgetting to explore the role of retrieval during encoding.