Item-Specific Encoding Produces an Additional Benefit of Directed Forgetting : Evidence From Intrusion Errors

List-method directed forgetting involves encoding 2 lists, between which half of the participants are told to forget List 1. When participants are free to study however they want, directed forgetting impairs List 1 recall and enhances List 2 recall in the forget group compared with a control remember group. In a large-scale experiment, the current work demonstrated that when item-specific encoding instructions were enforced during learning, directed forgetting impaired List 1 recall, but it did not enhance List 2 recall. This pattern was found regardless of whether encoding was incidental or intentional. Whenever directed forgetting did not enhance List 2 recall, it nevertheless reduced cross-list intrusions. These results indicate that directed forgetting can help differentiate memories from one another, thereby reducing intrusions from irrelevant competing memories

Inhibitory Selection Mechanisms in Clinically Healthy Older and Younger Adults

OBJECTIVE: Declines in working memory are a ubiquitous finding within the cognitive-aging literature. A unitary inhibitory selection mechanism that serves to guide attention toward task-relevant information and resolve interference from task-irrelevant information has been proposed to underlie such deficits. However, inhibition can occur at multiple time points in the memory-processing stream. Here, we tested whether the time point at which inhibition occurs in the memory-processing stream affects age-related memory decline. METHOD: Clinically healthy younger (n = 23) and older (n = 22) adults performed two similar item-recognition working memory tasks. In one task, participants received an instruction cue telling them which words to attend to followed by a memory set, promoting perceptual inhibition at the time of encoding. In the other task, participants received the instruction cue after they received the memory set, fostering inhibition of items already in memory. RESULTS: We found that older and younger adults differed in their ability to inhibit items both during encoding and when items had to be inhibited in memory but that these age differences were exaggerated when irrelevant information had to be inhibited from memory. These results provide insights into the mechanisms that support cognitive changes to memory processes in healthy aging

Oh, Honey, I Already Forgot That : Strategic Control of Directed Forgetting in Older and Younger Adults*

This article is about age-related differences in intentional forgetting of unwanted information. Imagine receiving medication and reading the directions on how to take it. Afterwards, the doctor tells you to take a different dosage at a different time from that printed on the label. Updating the directions may necessitate intentional forgetting of the earlier-learned information. The current article took one approach to examining this issue by examining age differences in the effectiveness of intentional forgetting using the popular list-method directed forgetting procedure invented by R. A. Bjork, LaBerge, and LeGrand (1968)

Dual Forgetting Operators in the Context of Weakest Sufficient and Strongest Necessary Conditions

Forgetting is an important concept in knowledge representation and automated reasoning with widespread applications across a number of disciplines. A standard forgetting operator, characterized in [Lin and Reiter'94] in terms of model-theoretic semantics and primarily focusing on the propositional case, opened up a new research subarea. In this paper, a new operator called weak forgetting, dual to standard forgetting, is introduced and both together are shown to offer a new more uniform perspective on forgetting operators in general. Both the weak and standard forgetting operators are characterized in terms of entailment and inference, rather than a model theoretic semantics. This naturally leads to a useful algorithmic perspective based on quantifier elimination and the use of Ackermman's Lemma and its fixpoint generalization. The strong formal relationship between standard forgetting and strongest necessary conditions and weak forgetting and weakest sufficient conditions is also characterized quite naturally through the entailment-based, inferential perspective used. The framework used to characterize the dual forgetting operators is also generalized to the first-order case and includes useful algorithms for computing first-order forgetting operators in special cases. Practical examples are also included to show the importance of both weak and standard forgetting in modeling and representation

Episodic memory and age-related deficits in inhibitory effectiveness

Background/Study Context: Age-related deficits in inhibitory control are well established in some areas of cognition, but evidence remains inconclusive in episodic memory. Two studies examined the extent to which a loss in inhibitory effectiveness—as measured by the extent of retrieval-induced forgetting (RIF)—is only detectable in (1) the very old, and (2) that a failure to control for noninhibitory mechanisms can lead to the misinterpretation of intact inhibition in episodic memory in the very old.  Methods: In Study 1, the authors employed a modified independent cue test—to provide as clean a measure of inhibitory functioning as possible—and examined whether there were significant differences in inhibitory effectiveness between younger-old (60–64years), old (65–69years), and older-old (70–74years) adults. In Study 2, the authors directly manipulated the contribution of output interference (a noninhibitory mechanism) to RIF in a group of young adults (18–34years), old (61–69years), and older-old (70–85years) adults.  Results: In Study 1, both younger-old (60–64years) and old (65–69years) adults demonstrated RIF on the modified independent cue test but older-old (70–74years) adults did not. In Study 2, all age groups demonstrated RIF in conditions where output interference was promoted. However, when output interference was controlled, only the young (18–34years) and old (61–69years) age groups demonstrated RIF; the older-old (70–85years) age group did not.  Conclusions: The findings suggest that inhibitory functioning remains intact in older adults under the age of 70years. However, a misleading impression can be formed of inhibitory effectiveness in adults over the age of 70 when memory tests do not exclude the use of noninhibitory processes, such as output interference. These two issues may partly explain the previous inconclusive findings regarding inhibitory deficits in normal aging

Selective voluntary forgetting in young and older adults

Aging is thought to involve a decline in executive-control capacities, although evidence regarding this claim is not always clear. Thus, although studies exist that suggest impoverished inhibitory memory control in older adults relative to younger adults, experiments with the list-method direct forgetting procedure have mostly failed to show adult-age differences in voluntary forgetting. In the present study we aimed to further study this issue by comparing young-old and young adults’ performance with the selective directed forgetting (SDF) procedure, which we assumed to involve higher demands of executive control than the standard nonselective procedure. Thus, on the basis of previous studies showing that a critical factor in finding adult-age differences in executive-control tasks is the overall challenge posed by the tasks, we predicted less SDF in older adults than in younger adults. Supporting our hypothesis, across three experiments we show evidence of older adults’ impoverished capacity to voluntarily forget episodic memories, although only when the task requires selective forgetting. Ours join other findings to suggest that sensitiveness to detect adult-age differences in cognitive control may strongly depend on the executive-control demands imposed by tasks

Brief wakeful resting can eliminate directed forgetting

When cued to intentionally forget previously encoded memories, participants typically show reduced recall of the memories on a later recall test. We examined how such directed forgetting is affected by a brief period of wakeful resting between encoding and test. Encoding was followed by a passive wakeful resting period in which subjects heard emotionally neutral music or perceived neutral pictures, or it was followed by an active distraction period in which subjects were engaged in counting or calculation tasks. Whereas typical directed forgetting was present after active distraction, the forgetting was absent after wakeful resting. The findings indicate that the degree to which people can intentionally forget memories is influenced by the cognitive activity that people engage in shortly after learning takes place. The results provide first evidence on the interplay between wakeful resting and intentional forgetting