Forgetting is frustrating, usually because it is unintended. Other times, one may purposely attempt to forget an event. A global theory of recognition and free recall that explains both types of forgetting and remembering from multiple list experiments is presented. The critical assumption of the model is that both intentional and unintentional forgetting are often due to contextual interference. Unintentional forgetting is the natural result of contextual changes between study and test. Intentional forgetting is accomplished by a rapid, metacognitively instigated change in mental context that renders to-be-forgotten information relatively inaccessible and renders to-be-remembered information more accessible (L. Sahakyan & C. M. Kelley, 2002). This occurs for both recognition and free recall. Implications for item-method directed forgetting, exclusion recognition, source memory, and encoding operations are discussed.

Atkinson and Shiffrin's (1968) dual-store model of memory includes structural aspects of memory along with control processes. The rehearsal buffer is a process by which items are kept in mind and long-term episodic traces are formed. The model has been both influential and controversial. Here, we describe a novel variant of Atkinson and Shiffrin's buffer model within the framework of the retrieving effectively from memory theory (REM; Shiffrin & Steyvers, 1997) that accounts for findings previously thought to be difficult for such models to explain. This model assumes a limited-capacity buffer where information is stored about items, along with information about associations between items and between items and the context in which they are studied. The strength of association between items and context is limited by the number of items simultaneously occupying the buffer (Lehman & Malmberg, 2009). The contents of the buffer are managed by complementary processes of rehearsal and compartmentalization (Lehman & Malmberg, 2011). New findings that directly test a priori predictions of the model are reported, including serial position effects and conditional and first recall probabilities in immediate and delayed free recall, in a continuous distractor paradigm, and in experiments using list-length manipulations of single-item and paired-item study lists.

Practicing retrieval is a powerful way to promote learning and long-term retention. This chapter addresses the theoretical underpinnings of retrieval-based learning. We review methodological issues in retrieval practice research, identify key findings to be Psychology of Learning and Motivation, Volume 61 # 2014 Elsevier Inc. ISSN 0079-7421 All rights reserved. http://dx. 237accounted for, and evaluate current candidate theories. We propose an episodic context account of retrieval-based learning, which explains retrieval practice in terms of context reinstatement, context updating, and restriction of the search set. Retrieval practice involves attempting to reinstate a prior learning context, and when retrieval is successful, the representation of context is updated to include features of retrieved contexts and the current context. Future retrieval is enhanced because updated context representations can be used to restrict the search set and hone in on a desired target. The context account accommodates a wide variety of phenomena in the retrieval practice literature and provides a comprehensive and cohesive account of retrieval-based learning.

We tested the predictions of 2 explanations for retrieval-based learning; while the elaborative retrieval hypothesis assumes that the retrieval of studied information promotes the generation of semantically related information, which aids in later retrieval (Carpenter, 2009), the episodic context account proposed by Karpicke, Lehman, and Aue (in press) assumes that retrieval alters the representation of episodic context and improves one's ability to guide memory search on future tests. Subjects studied multiple word lists and either recalled each list (retrieval practice), did a math task (control), or generated associates for each word (elaboration) after each list. After studying the last list, all subjects recalled the list and, after a 5-min delay, recalled all lists. Analyses of correct recall, intrusions, response times, and temporal clustering dissociate retrieval practice from elaboration, supporting the episodic context account.

The long-term effects of the compartmentalization of task-irrelevant memories were investigated using a directed forgetting procedure. Many models tacitly assume the persistence of the costs and benefits of directed forgetting or otherwise fail to predict what factors might reduce or eliminate them. In contrast, a retrieving effectively from memory model (REM; Lehman & Malmberg, 2009) predicts that intentional forgetting should only be observed for free recall when temporal context is used to probe memory. By manipulating whether study lists were constructed from category exemplars or from a random set of words, and by either providing temporal or category cues at test, we tested the prediction. The effects of directed forgetting were eliminated when categorized lists were studied and category cues were provided. When categorized lists were used but category cues were not provided, the usual costs and benefits of directed forgetting were observed. These results specify the conditions under which the consequences of intentional forgetting can be overcome.