Peter F. Delaney

Models of Working Memory: Long-Term Working Memory as an Alternative to Capacity Models of Working Memory in Everyday Skilled Performance

FIVE CENTRAL FEATURES OF THE THEORY (1) We define working memory in terms of its function, namely maintaining efficient selective access to information that is needed to complete a given task. This function can be achieved in everyday skilled performance by a wide range of different mechanisms. In contrast, traditional short-term working memory employs only a small subset of those alternatives. (2) The amount of information that can be maintained in accessible form in working memory for a specific task is not limited by a fixed capacity. As part of the extended skill acquisition necessary to attain very high levels of performance, experts acquire knowledge and skills to rapidly encode information in long-term memory such that the information can be efficiently accessed with retrieval cues (longterm working memory or LT-WM) whenever it is later needed to complete the task. Similar acquired mechanisms mediate the large working memory in skilled everyday performance. (3) LT-WM is mediated by associative recall from long-term memory, and to function reliably it provides different types of mechanisms for overcoming the problems of interference resulting from repeated associations to related retrieval cues. (4) LT-WM reflects a complex skill acquired to meet the particular demands of future accessibility for information with tasks within a particular domain of expertise. Domain-relevant skills, knowledge, and procedures for the task are so tightly integrated into the skills for encoding of information that the traditional assumption of a strict separation between memory, knowledge, and procedures is not valid for skilled performance. […]

Spacing and Testing Effects: A Deeply Critical, Lengthy, and At Times Discursive Review of the Literature

Abstract What appears to be a simple pattern of results—distributed-study opportunities usually produce better memory than massed-study opportunities—turns out to be quite complicated. Many “impostor” effects such as rehearsal borrowing, strategy changes during study, recency effects, and item skipping complicate the interpretation of spacing experiments. We suggest some best practices for future experiments that diverge from the typical spacing experiments in the literature. Next, we outline the major theories that have been advanced to account for spacing studies while highlighting the critical experimental evidence that a theory of spacing must explain. We then propose a tentative verbal theory based on the SAM/REM model that utilizes contextual variability and study-phase retrieval to explain the major findings, as well as predict some novel results. Next, we outline the major phenomena supporting testing as superior to restudy on long-term retention tests, and review theories of the testing phenomenon, along with some possible boundary conditions. Finally, we suggest some ways that spacing and testing can be integrated into the classroom, and ask to what extent educators already capitalize on these phenomena. Along the way, we present several new experiments that shed light on various facets of the spacing and testing effects.

Directed forgetting in incidental learning and recognition testing: Support for a two-factor account

Instructing people to forget a list of items often leads to better recall of subsequently studied lists (known as the benefits of directed forgetting). The authors have proposed that changes in study strategy are a central cause of the benefits (L. Sahakyan & P. F. Delaney, 2003). The authors address 2 results from the literature that are inconsistent with their strategy-based explanation: (a) the presence of benefits under incidental learning conditions and (b) the absence of benefits in recognition testing. Experiment 1 showed that incidental learning attenuated the benefits compared with intentional learning, as expected if a change of study strategy causes the benefits. Experiment 2 demonstrated benefits using recognition testing, albeit only when longer lists were used. Memory for source in directed forgetting was also explored using multinomial modeling. Results are discussed in terms of a 2-factor account of directed forgetting.

Remembering to Forget The Amnesic Effect of Daydreaming

Daydreaming mentally transports people to another place or time. Many daydreams are similar in content to the thoughts that people generate when they intentionally try to forget. Thus, thoughts like those generated during daydreaming can cause forgetting of previously encoded events. We conducted two experiments to test the hypothesis that daydreams that are more different from the current moment (e.g., in distance, time, or circumstance) will result in more forgetting than daydreams that are less different from the current moment, because they result in a greater contextual shift. Daydreaming was simulated in the laboratory via instructions to engage in a diversionary thought. Participants learned a list of words, were asked to think about autobiographical memories, and then learned a second list of words. They tended to forget more words from the first list when they thought about their parents’ home than when they thought about their current home (Experiment 1). They also tended to forget more when they thought about an international vacation than when they thought about a domestic vacation (Experiment 2). These results support a context-change account of the amnesic effects of daydreaming.

Unexpected Costs of High Working Memory Capacity Following Directed Forgetting and Contextual Change Manipulations

Greater working memory capacity is usually associated with greater ability to maintain information in the face of interruptions. In two experiments, we found that some types of interruptions actually lead to greater forgetting among high-span people than among low-span people. Specifically, an instruction designed to change mental context resulted in significant forgetting for high-span people but minimal forgetting among the low-span people. Intentional forgetting instructions also resulted in greater forgetting among higher working memory capacity participants than among lower working memory capacity participants. A candidate explanation called the intensified context shift hypothesis is proposed which suggests that high-span people are more context dependent than low-span people.

Oh, honey, I already forgot that: strategic control of directed forgetting in older and younger adults.

Two experiments investigated list-method directed forgetting with older and younger adults. Using standard directed forgetting instructions, significant forgetting was obtained with younger but not older adults. However, in Experiment 1 older adults showed forgetting with an experimenter-provided strategy that induced a mental context change--specifically, engaging in diversionary thought. Experiment 2 showed that age-related differences in directed forgetting occurred because older adults were less likely than younger adults to initiate a strategy to attempt to forget. When the instructions were revised to downplay their concerns about memory, older adults engaged in effective forgetting strategies and showed significant directed forgetting comparable in magnitude to younger adults. The results highlight the importance of strategic processes in directed forgetting.

Self-evaluation as a moderating factor of strategy change in directed forgetting benefits

In list method directed forgetting, instructing people to forget a studied word list usually results in better recall for a newly studied list. Sahakyan and Delaney (2003) have suggested that these benefits are due to a change in encoding strategy that occurs between the study of the first list and the study of the second list. To investigate what might mediate such strategy change decisions, in two experiments we induced bothforget and remember participants to evaluate their memory performance on the two lists. In Experiment 1, they were asked to explicitly recall the items from the first list before studying the second list. In Experiment 2, after the study of the first list, the participants provided a rapid aggregate judgment of learning. Evaluation eliminated the differences between the forget and remember groups for the second list in both experiments, because the remember group achieved recall levels comparable to those for the forget group. The role of performance evaluation in mediating directed forgetting benefits is discussed.

List-Method Directed Forgetting in Cognitive and Clinical Research: A Theoretical and Methodological Review

The primary purpose of this chapter is to provide an up-to-date review of the twenty-first century research and theory on list-method directed forgetting (DF) and related phenomena like the context-change effect. Many researchers have assumed that DF is diagnostic of inhibition, but we argue for an alternative, noninhibitory account and suggest reinterpretation of earlier findings. We first describe what DF is and the state of the art with regard to measuring the effect. Then, we review recent evidence that brings DF into the family of effects that can be explained by global memory models. The process-based theory we advocate is that the DF impairment arises from mental context change and that the DF benefits emerge mainly but perhaps not exclusively from changes in encoding strategy. We review evidence (some new to this paper) that strongly suggests that DF arises from the engagement of controlled forgetting strategies that are independent of whether people believed the forget cue or not. Then we describe the vast body of literature supporting that forgetting strategies result in contextual change effects, as well as point out some inconsistencies in the DF literature that need to be addressed in future research. Next, we provide evidence—again, some of it new to this chapter—that the reason people show better memory after a forget cue is that they change encoding strategies. In addition to reviewing the basic research with healthy population, we reinterpret the evidence from the literature on certain clinical populations, providing a critique of the work done to date and outlining ways of improving the methodology for the study of DF in special populations. We conclude with a critical discussion of alternative approaches to understanding DF.Abstract The primary purpose of this chapter is to provide an up-to-date review of the twenty-first century research and theory on list-method directed forgetting (DF) and related phenomena like the context-change effect. Many researchers have assumed that DF is diagnostic of inhibition, but we argue for an alternative, noninhibitory account and suggest reinterpretation of earlier findings. We first describe what DF is and the state of the art with regard to measuring the effect. Then, we review recent evidence that brings DF into the family of effects that can be explained by global memory models. The process-based theory we advocate is that the DF impairment arises from mental context change and that the DF benefits emerge mainly but perhaps not exclusively from changes in encoding strategy. We review evidence (some new to this paper) that strongly suggests that DF arises from the engagement of controlled forgetting strategies that are independent of whether people believed the forget cue or not. Then we describe the vast body of literature supporting that forgetting strategies result in contextual change effects, as well as point out some inconsistencies in the DF literature that need to be addressed in future research. Next, we provide evidence—again, some of it new to this chapter—that the reason people show better memory after a forget cue is that they change encoding strategies. In addition to reviewing the basic research with healthy population, we reinterpret the evidence from the literature on certain clinical populations, providing a critique of the work done to date and outlining ways of improving the methodology for the study of DF in special populations. We conclude with a critical discussion of alternative approaches to understanding DF.

The selective directed forgetting effect: Can people forget only part of a text?

Participants studied sentences describing two different characters and then were told to forget the sentences about only one of the characters. A second list contained sentences attributed to a third character. Subsequently, they received a recall test on the sentences about the original two characters. When the sentences could be thematically integrated, participants showed no directed forgetting relative to a control group that was never told to forget. However, with unrelated sentences, participants selectively forgot the target characters sentences without forgetting the other characters sentences. This selective directed forgetting effect is a novel empirical result. We interpret the results as consistent with Radvanskys (1999) ideas about inhibition with textual materials.

Rehearsal Strategies Can Enlarge or Diminish the Spacing Effect: Pure versus Mixed Lists and Encoding Strategy.

Using 5 experiments, the authors explored the dependency of spacing effects on rehearsal patterns. Encouraging rehearsal borrowing produced opposing effects on mixed lists (containing both spaced and massed repetitions) and pure lists (containing only one or the other), magnifying spacing effects on mixed lists but diminishing spacing effects on pure lists. Rehearsing with borrowing produced large spacing effects on mixed lists but not on pure lists for both free recall (Experiment 1) and recognition (Experiment 2). In contrast, rehearsing only the currently visible item produced spacing effects on both mixed lists and pure lists in free recall (Experiment 3) and recognition (Experiment 4). Experiment 5 demonstrated these effects using a fully within-subjects design. Rehearse-aloud protocols showed that rehearsal borrowing redistributed study from massed to spaced items on mixed lists, especially during massed presentations.