Intentional suppression of unwanted memories grows more difficult as we age

Everything you ever wanted to know about the Think/No-Think task, but forgot to ask

The Think/No-Think (TNT) task has just celebrated 20 years since its inception, and its use has been growing as a tool to investigate the mechanisms underlying memory control and its neural underpinnings. Here, we present a theoretical and practical guide for designing, implementing, and running TNT studies. For this purpose, we provide a step-by-step description of the structure of the TNT task, methodological choices that can be made, parameters that can be chosen, instruments available, aspects to be aware of, systematic information about how to run a study and analyze the data. Importantly, we provide a TNT training package (as Supplementary Material), that is, a series of multimedia materials (e.g., tutorial videos, informative HTML pages, MATLAB code to run experiments, questionnaires, scoring sheets, etc.) to complement this method paper and facilitate a deeper understanding of the TNT task, its rationale, and how to set it up in practice. Given the recent discussion about the replication crisis in the behavioral sciences, we hope that this contribution will increase standardization, reliability, and replicability across laboratories.

Suppressing memory associations impacts decision-making preference: Evidence from the think/no-think paradigm

Recent research has suggested that episodic memory can guide our decision-making. Forgetting is one essential characteristic of memory. If certain memories are suppressed to be forgotten, decisions that rely on such memories should be impacted. So far, little research has examined whether suppression of episodic memory would impact decision-making. In the current pre-registered study, the effect of memory suppression on subsequent reinforcement decision-making was examined by combining the Think/No-think paradigm and a reinforcement decision-making task. We found that suppressing memories of learned associations significantly impaired recollected memories of those associations, and participants' decision bias disappeared after their memory associations were suppressed. Furthermore, the more memory associations participants recalled, the higher decision preferences they exhibited. Our findings provide additional support for the role of episodic memory in reinforcement decision-making, and suggest that suppressing memory associations can lead to behavioral consequences.

Childhood abuse as a mediator of the relationship between early family socio-economic status and geriatric depression: A population-based study in China

Previous studies have suggested that childhood socioeconomic status (SES) is linked to geriatric depressive symptoms in many developed countries. However, the potential pathways of the relationship between childhood SES and geriatric depressive symptoms need to be further explored. This study aimed to assess the mediating effect of being abused during childhood on the association between childhood SES and geriatric depressive symptoms, using evidence from a longitudinal study in China. The study cohort included 8137 individuals. Childhood abuse was defined as experiences related to parental violence, sibling abuse, school violence, community violence, and parental quarrel. Results indicated poor childhood SES was associated significantly with geriatric depressive symptoms. The indirect effect of poor childhood SES to high geriatric depressive risk through community violence, sibling abuse, school violence, and parental quarrel were 0.02, 0.01, 0.02, and 0.01, respectively. Our findings shed new light on the literature regarding the impact of childhood SES on elderly depressive symptoms. Furthermore, childhood SES demonstrated a significant correlation with geriatric depressive symptoms through bullying behaviors. The findings highlight the need to promote both childhood social welfare and psychological well-being within the elderly population.

On the role of inhibition in suppression-induced forgetting

Suppressing retrieval of unwanted memories can cause forgetting, an outcome often attributed to the recruitment of inhibitory control. This suppression-induced forgetting (SIF) generalizes to different cues used to test the suppressed content (cue-independence), a property taken as consistent with inhibition. But does cue-independent forgetting necessarily imply that a memory has been inhibited? Tomlinson et al. (Proc Natl Acad Sci 106:15588-15593, 2009) reported a surprising finding that pressing a button also led to cue-independent forgetting, which was taken as support for an alternative interference account. Here we investigated the role of inhibition in forgetting due to retrieval suppression and pressing buttons. We modified Tomlinson et al.'s procedure to examine an unusual feature they introduced that may have caused memory inhibition effects in their experiment: the omission of explicit task-cues. When tasks were uncued, we replicated the button-press forgetting effect; but when cued, pressing buttons caused no forgetting. Moreover, button-press forgetting partially reflects output-interference effects at test and not a lasting effect of interference. In contrast, SIF occurred regardless of these procedural changes. Collectively, these findings indicate that simply pressing a button does not induce forgetting, on its own, without confounding factors that introduce inhibition into the task and that inhibition likely underlies SIF.

Task compliance predicts suppression-induced forgetting in a large sample

Suppression-induced forgetting (SIF) refers to a memory impairment resulting from repeated attempts to stop the retrieval of unwanted memory associates. SIF has become established in the literature through a growing number of reports built upon the Think/No-Think (TNT) paradigm. Not all individuals and not all reported experiments yield reliable forgetting, however. Given the reliance on task instructions to motivate participants to suppress target memories, such inconsistencies in SIF may reasonably owe to differences in compliance or expectations as to whether they will again need to retrieve those items (on, say, a final test). We tested these possibilities on a large (N = 497) sample of TNT participants. In addition to successfully replicating SIF, we found that the magnitude of the effect was significantly and negatively correlated with participants’ reported compliance during the No-Think trials. This pattern held true on both same- and independent-probe measures of forgetting, as well as when the analysis was conditionalized on initial learning. In contrast, test expectancy was not associated with SIF. Supporting previous intuition and more limited post-hoc examinations, this study provides robust evidence that a lack of compliance with No-Think instructions significantly compromises SIF. As such, it suggests that diminished effects in some studies may owe, at least in part, to non-compliance—a factor that should be carefully tracked and/or controlled. Motivated forgetting is possible, provided that one is sufficiently motivated and capable of following the task instructions.

Age, Sex, and Inhibitory Control: Identifying A Specific Impairment in Memorial, But Not Perceptual Inhibition in Older Women

Objectives

Declines in the ability to inhibit information, and the consequences to memory of unsuccessful inhibition, have been frequently reported to increase with age. However, few studies have investigated whether sex moderates such effects. Here, we examined whether inhibitory ability may vary as a function of age and sex, and the interaction between these two factors.

Method

202 older (mean age = 69.40 years) and younger (mean age =30.59 years) participants who had equivalent educational attainment and self-reported health completed 2 tasks that varied only in the time point at which inhibition should occur: either prior to, or after, encoding.

Results

While we did not find evidence for age or sex differences in inhibitory processes when information needed to be inhibited prior to encoding, when encoded information being actively held in working memory needed to be suppressed, we found that older women were particularly impaired relative to both younger women and men of either age group.

Discussion

These results provide further support for the presence of memorial inhibitory deficits in older age, but add nuance by implicating biological sex as an important mediator in this relationship, with it more difficult for older women to inhibit what was once relevant in memory.

Cortical thickness in the right inferior frontal gyrus mediates age-related performance differences on an item-method directed forgetting task

Evidence suggests that older adults have difficulty relative to younger adults in forgetting irrelevant information. Here we sought to understand the physical basis of this deficit by investigating the relationship between cortical thickness and intentional forgetting, using an item-method directed forgetting task. We tested younger (n = 44) and older (n = 54) adults' memories for words that they were instructed to either remember or to forget, and then extracted cortical thickness values from brain regions previously shown, using functional neuroimaging, to be associated with memory suppression, including the right inferior frontal gyrus, the right postcentral gyrus and the left superior/middle frontal gyrus. Results from a parallel mediation model indicated that variations in cortical thickness in the right inferior frontal gyrus, but not the right postcentral gyrus or left superior/middle frontal gyrus, partially explained age-related differences in directed forgetting: older adults with thinner cortices in this area showed worse forgetting ability. This is the first study to explore how neuromorphological differences affect the ability to intentionally suppress items in memory. The results suggest that age-related differences in directed forgetting may be partly driven by cortical thickness in a brain structure known to be functionally involved in directed forgetting, and inhibitory control more broadly, supporting a contribution of deficient inhibition to this phenomenon.

Memory Suppression Ability can be Robustly Predicted by the Internetwork Communication of Frontoparietal Control Network

Memory suppression (MS) is essential for mental well-being. However, no studies have explored how intrinsic resting-state functional connectivity (rs-FC) predicts this ability. Here, we adopted the connectome-based predictive modeling (CPM) based on the resting-state fMRI data to investigate whether and how rs-FC profiles in predefined brain networks (the frontoparietal control networks or FPCN) can predict MS in healthy individuals with 497 participants. The MS ability was assessed by MS-induced forgetting during the think/no-think paradigm. The results showed that FPCN network was especially informative for generating the prediction model for MS. Some regions of FPCN, such as middle frontal gyrus, superior frontal gyrus and inferior parietal lobe were critical in predicting MS. Moreover, functional interplay between FPCN and multiple networks, such as dorsal attention network (DAN), ventral attention network (VAN), default mode network (DMN), the limbic system and subcortical regions, enabled prediction of MS. Crucially, the predictive FPCN networks were stable and specific to MS. These results indicated that FPCN flexibility interacts with other networks to underpin the ability of MS. These would also be beneficial for understanding how compromises in these functional networks may have led to the intrusive thoughts and memories characterized in some mental disorders.

Age Differences in the Subcomponents of Executive Functioning

OBJECTIVES

Across the life span, deficits in executive functioning (EF) are associated with poor behavioral control and failure to achieve goals. Though EF is often discussed as one broad construct, a prominent model of EF suggests that it is composed of three subdomains: inhibition, set shifting, and updating. These subdomains are seen in both younger (YA) and older adults (OA), with performance deficits across subdomains in OA. Therefore, our goal was to investigate whether subdomains of EF might be differentially affected by age, and how these differences may relate to broader global age differences in EF.

METHODS

To assess these age differences, we conducted a meta-analysis at multiple levels, including task level, subdomain level, and of global EF. Based on previous work, we hypothesized that there would be overall differences in EF in OA.

RESULTS

Using 1,268 effect sizes from 401 articles, we found overall differences in EF with age. Results suggested that differences in performance are not uniform, such that variability in age effects emerged at the task level, and updating was not as affected by age as other subdomains.

DISCUSSION

These findings advance our understanding of age differences in EF, and stand to inform early detection of EF decline.

Disrupted memory inhibition in dementia of Alzheimer's type

Cognitive inhibition has been suggested to deteriorate in Alzheimer's disease. While numerous studies with different experimental paradigms found evidence on impaired inhibition in attention and memory, evidence in favour of intact memory inhibition has been reported with regard to the phenomenon of retrieval-induced forgetting (Moulin et al., 2002). Here, we adapted the previously used paradigm in order to reduce the contribution of non-inhibitory processes and examined whether retrieval-induced forgetting could still be observed in a sample of participants with diagnosed Alzheimer's disease. In contrast to the previous finding, we found that retrieval-induced forgetting only occurred in an age-matched control group. These results suggest that inhibitory deficits in Alzheimer's disease also generalize to memory inhibition that resolves interference occurring during retrieval, whereas effects of retrieval-induced forgetting may still occur when non-inhibitory causes, such as, blocking by previously retrieved content, are not precluded.

Association between Childhood Suicidal Ideation and Geriatric Depression in Japan: A Population-Based Cross-Sectional Study

Adverse childhood experiences (ACEs) are assumed to increase the risk of depression in late life via development of poor mental health conditions; however, the association between mental distress in childhood and geriatric depression has not been directly examined. This study examined the association between childhood suicidal ideation and geriatric depression, using population-based, cross-sectional survey data from 1140 community-dwelling, functionally independent older adults in Wakuya City, Japan. We assessed childhood suicidal ideation by asking the participants whether they had seriously considered attempting suicide before the age of 18, together with geriatric depression, using the Japanese version of the 15-item Geriatric Depression Scale. Poisson regression was applied to adjust for potential confounders and mediators. In total, 6.1% of the participants reported childhood suicidal ideation. After adjustment for sex, age, personality attributes and ACEs, childhood suicidal ideation was positively associated with geriatric depression prevalence ratio [PR]: 1.40, 95% Confidence Interval (95%CI): 1.04-1.88). The increased PR of geriatric depression remained significant, even after further adjustment for adulthood socio-economic status, recent life stressors and current health status (PR: 1.38, 95%CI: 1.02-1.88). Further prospective studies are warranted, but efforts to deliver mental health services to children with suicidal ideation potentially diminish the highly prevalent geriatric depression.

Wanting to eat matters: Negative affect and emotional eating were associated with impaired memory suppression of food cues

OBJECTIVE

Previous studies have linked emotional eating with negative affect and decreased inhibitory control. However, studies on inhibitory control have generally focused on motor inhibition. How to stop higher-level cognitive processes, such as food-related memory retrieval or voluntary thoughts, received few direct investigation in field of food intake or food-related decision making. The current study, adopting Anderson and Green's Think/No-Think paradigm, aimed to investigate the relationship between emotional eating, negative affect and food-related memory suppression.

METHOD

Sixty-one young females participated in the current study, during which they finished food specific Think/No-Think task. Their positive and negative affect and eating style were measured using Positive Affect and Negative Affect Schedule and Dutch Eating Behavior Question. The reward value of the food item used in the Think/No-Think task was measured using liking and wanting ratings.

RESULTS

As hypothesized, negative affect and emotional eating were associated with decreased memory suppression of palatable food cues. Further analysis showed that higher emotional eating was associated with greater wanting only among the food items which were previously suppressed however remembered later.

DISCUSSION

The current study presents the first evidence that negative affect and emotional eating were associated with impaired memory suppression of palatable food cues, and it provided insight into the interaction between reward valuation for the food cues and hippocampal memory mechanisms during retrieval suppression.

Time to Forget

Abstract. Emerging technologies at work encourage the collection and storage of large amounts of data. However, these vast quantities of data are likely to impair efficient work decisions by employees over time, with negative consequences for the organization. As human attention increasingly represents the scarce resource at work, the present paper focuses on a mechanism of attentional control at work – namely, intentionally forgetting unwanted and outdated internal (e. g., knowledge) and external (e. g., digital objects) information. The purpose of this paper is threefold. Based on a short review of the research on intentional forgetting, a prototypical conceptualization of an interactive assistive system (Dare2Del, cognitive companion) is provided, which should support employees in temporally ignoring or permanently deleting outdated information. Then, we completed a critical incident study to examine why and when employees might want to forget information at work, and to identify in which working situations an assistive system should be particularly helpful.

Psychological Adjustment of Aging Vietnam Veterans: The Role of Social Network Ties in Reengaging with Wartime Memories

It is projected that by 2020 there will be 8.7 million veterans over the age of 65 years, more than half (64%) of whom served during the Vietnam War. The effects of military service on mental health and well-being may be more pronounced later in life among those who served in Vietnam than prior cohorts of veterans. Many veterans confront and rework their wartime memories later in life in an attempt to find meaning and coherence, engaging in a process referred to as Later-Adulthood Trauma Reengagement (LATR). LATR often occurs in the context of other stressors that are a normative part of aging, such as role transitions (e.g., retirement), declines in physical health, and the death of close others (e.g., spouses), perhaps because these events trigger reminiscence. Importantly, LATR may result in either positive (e.g., acceptance) or negative (e.g., distress) psychological outcomes. It has been suggested that the presence of social/environmental resources, including socioemotional support, may aid veterans in successfully navigating LATR. We, therefore, review relevant areas of research to delineate the role that various layers of social context may play in -helping - or hindering - aging Vietnam veterans as they navigate LATR in the context of normative late-life stressors. We conclude by offering fruitful directions for future research and applied implications for intervention efforts.

Theta oscillations show impaired interference detection in older adults during selective memory retrieval

Seemingly effortless tasks, such as recognizing faces and retrieving names, become harder as we age. Such difficulties may be due to the competition generated in memory by irrelevant information that comes to mind when trying to recall a specific face or name. It is unknown, however, whether age-related struggles in retrieving these representations stem from an inability to detect competition in the first place, or from being unable to suppress competing information once interference is detected. To investigate this, we used the retrieval practice paradigm, shown to elicit memory interference, while recording electrophysiological activity in young and older adults. In two experiments, young participants showed Retrieval-Induced Forgetting (RIF), reflecting the suppression of competing information, whereas older adults did not. Neurally, mid-frontal theta power (~4-8 Hz) during the first retrieval cycle, a proxy for interference detection, increased in young compared to older adults, indicating older adults were less capable of detecting interference. Moreover, while theta power was reduced across practice cycles in younger adults, a measure of interference resolution, older adults did not show such a reduction. Thus, in contrast with younger adults, the lack of an early interference detection signal rendered older adults unable to recruit memory selection mechanisms, eliminating RIF.

Influence of age on the effects of lying on memory

False memories are elicited from exposure to misleading information. It is possible that self-provided misinformation, or lying, has similar effects. We hypothesized that lying impairs memory for younger adults, as increased cognitive control, necessary to inhibit a truthful response, comes at the expense of retaining veridical information in memory. Because older adults show deficits in cognitive control, we hypothesized their memory is unaffected by lying. In the present study, participants made truthful and deceptive responses on a computer while EEG data were recorded. We investigated medial frontal negativity (MFN), an ERP component associated with deception and cognitive control, which may be differentially generated across age groups due to differences in cognitive control. Unexpectedly, results revealed that older adults showed reduced accurate memory for items to which they previously lied compared to younger adults. There were no age differences in correct memory for truth items. We did not find the expected MFN effect, however results revealed long-lasting negative slow waves (NSW) to lie items across age in the pre-response period and following the response cue, suggesting the role of working memory processes in deception. These findings demonstrate that lying is another source of misinformation and influences memory differently across the lifespan.

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.

Directed forgetting in organisations: the positive effects of decision support systems on mental resources and well-being

Decision makers in organisations are often overtaxed by huge amounts of information in daily business processes. As a potential support strategy, this study examined 'directed forgetting' (Bjork, 1970) in a simulated sales planning scenario. We assumed that the availability of a computer-based decision support system (DSS) triggers the forgetting of decision-related background information. Such directed forgetting should not only release memory capacities for additional tasks but also enhance decision quality and decrease strain of decision makers. Assumptions were tested in an experimental study with N = 90 participants. Consistent with our assumptions, results revealed a higher recall of decision-unrelated information, higher decision quality and higher well-being when participants could use a DSS as compared to two Control conditions without a DSS. Moreover, directed forgetting effects were qualified by participants' trust in the DSS. This study provides the first evidence for directed forgetting effects cued by information systems in a business context. Practitioner summary: Information overload is an increasing challenge in modern business organisations. Extending findings from basic memory research, this study shows that availability of a computer-based decision support system triggers forgetting of decision-related background information, which in turn increases users' mental resources for additional tasks, decision quality, and well-being.

The implementation of expectancy-based strategic processes is delayed in normal aging

The present research examined if the time needed to implement expectancy-based strategic processes is different in younger and healthy older adults. In four experiments participants from both age groups performed different strategic priming tasks. These included a greater proportion of incongruent (or unrelated; 80%) than of congruent (or related; 20%) trials. With this procedure performance is worse for congruent (less frequent) than for incongruent (more frequent) trials, thus demonstrating that the relative frequency information can be used to predict the upcoming target. To explore the time course of these expectancy-based effects, the prime-target SOA was manipulated across experiments through a range of intervals: 400, 1000 and 2000 ms. Participants also performed a change localization and an antisaccade task to assess their working memory and attention control capacities. The results showed that increases in age were associated with (a) a slower processing-speed, (b) a decline in WM capacity, and (c) a decreased capacity for attentional control. The latter was evidenced by a disproportionate deterioration of performance in the antisaccade trials compared to the prosaccade ones in the older group. Results from the priming tasks showed a delay in the implementation of expectancies in older adults. Whereas younger participants showed strategic effects already at 1000 ms, older participants consistently failed to show expectancy-based priming during the same interval. Importantly, these effects appeared later at 2000 ms, being similar in magnitude to those by the younger participants and unaffected by task practice. The present findings demonstrate that the ability to implement expectancy-based strategies is slowed down in normal aging.

What doesn't kill you makes you stronger: Psychological trauma and its relationship to enhanced memory control

Control processes engaged in halting the automatic retrieval of unwanted memories have been shown to reduce the later recallability of the targets of suppression. Like other cognitive skills that benefit from practice, we hypothesized that memory control is similarly experience dependent, such that individuals with greater real-life experience at stopping retrieval would exhibit better inhibitory control over unwanted memories. Across two experiments, we found that college students reporting a greater history of trauma exhibited more suppression-induced forgetting of both negative and neutral memories than did those in a matched group who had reported experiencing little to no trauma. The association was especially evident on a test of suppression-induced forgetting involving independent retrieval cues that are designed to better isolate the effects of inhibitory control on memory. Participants reporting more trauma demonstrated greater generalized forgetting of suppressed material. These findings raise the possibility that, given proper training, individuals can learn to better manage intrusive experiences, and are broadly consistent with the view that moderate adversity can foster resilience later in life. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

On the Very-Long-Term Effect of Managing One's Own Memory: The Intention to Forget Improves Recognition After a Year's Delay

While such factors as demand characteristics, encoding, and retrieval inhibition were shown to be significant in producing the directed forgetting effect, no attention was paid to whether the intention to manage one's own memory, per se, matters. In the present article, we addressed this important gap in the literature. To control the quality of encoding we ensured that both the to-be-remembered (TBR) and to-be-forgotten (TBF) items were genuinely learned before the manipulation. We used extremely long delays between the memory instructions and testing to release inhibition associated with the content of instructions. 98 participants demonstrated flawless recall of 12 Russian - made up language word pairs. They then viewed each Russian word from a pair once, with randomized instructions "Forget", "Remember", "Repeat", or a short cognitive task. Self-reports on the mnemonic strategies were collected. Free recall and recognition tests were administered three times - 45 minutes, a month and a year (N = 58) later. Despite a strong incentive to recall all word pairs, fewer TBF pairs were recalled in comparison with TBR pairs, both after 45 minutes and after one month's delay. Recognition among all conditions was equally high. A year later free recall was close to zero. In contrast, the TBR and TBF pairs were recognized equally better than pairs presented in "Repeat" and "Task" conditions. Thus, our results show that the intention to manage one's own memory enhances the accessibility of memories at a very long time delay, no matter what type of instruction is issued.

Motivated forgetting reduces veridical memories but slightly increases false memories in both young and healthy older people

The aim of the current study is to examine the effects of motivated forgetting and aging on true and false memory. Sixty young and 54 healthy older adults were instructed to study two lists of 18 words each. Each list was composed of three sets of six words associated with three non-presented critical words. After studying list 1, half of the participants received the instruction to forget List 1, whereas the other half received the instruction to remember List 1. Next, all the subjects studied list 2; finally, they were asked to remember the words studied in both lists. The results showed that when participants intended to forget the studied List 1, they were less likely to recall the studied words, but more likely to intrude the critical words. That is, we can intentionally forget something but this can also entail the intrusion of some related false memories.

Predictors of PTSD 40 years after combat: Findings from the National Vietnam Veterans longitudinal study

BACKGROUND

Few studies have longitudinally examined predictors of posttraumatic stress disorder (PTSD) in a nationally representative sample of US veterans. We examined predictors of warzone-related PTSD over a 25-year span using data from the National Vietnam Veterans Longitudinal Study (NVVLS).

METHODS

The NVVLS is a follow-up study of Vietnam theater veterans (N = 699) previously assessed in the National Vietnam Veterans Readjustment Study (NVVRS), a large national-probability study conducted in the late 1980s. We examined the ability of 22 premilitary, warzone, and postmilitary variables to predict current warzone-related PTSD symptom severity and PTSD symptom change in male theater veterans participating in the NVVLS. Data included a self-report Health Questionnaire survey and a computer-assisted telephone Health Interview Survey. Primary outcomes were self-reported PTSD symptoms assessed by the PTSD Checklist for DSM-5 (PCL 5) and Mississippi PTSD Scale (M-PTSD).

RESULTS

Predictors of current PTSD symptoms most robust in hierarchical multivariable models were African-American race, lower education level, negative homecoming reception, lower current social support, and greater past-year stress. PTSD symptoms remained largely stable over time, and symptom exacerbation was predicted by African-American race, lower education level, younger age at entry into Vietnam, greater combat exposure, lower current social support, and greater past-year stressors.

CONCLUSIONS

Findings confirm the robustness of a select set of risk factors for warzone-related PTSD, establishing that these factors can predict PTSD symptom severity and symptom change up to 40 years postdeployment.

Perceptual and memory inhibition deficits in clinically healthy older adults are associated with region-specific, doubly dissociable patterns of cortical thinning

Converging evidence suggests that the cognitive control processes that enable the inhibition of irrelevant information on a perceptual versus a memorial basis are qualitatively different and are underlain by unique neural systems that may be affected differentially in aging. In the current study, we investigated whether individual differences in performance on these 2 types of inhibitory processes were attributable to region-specific patterns of cortical thinning. Clinically healthy older adults completed a pair of behavioral memory and perceptual inhibition tasks and then underwent structural brain imaging. We found that worse memory inhibition was associated with reduced cortical thickness in the left ventral lateral prefrontal cortex (VLPFC), an area that has been functionally associated with memory inhibition, but not in either the right or left superior parietal lobule (SPL), areas that have been functionally associated with perceptual inhibition. On the contrary, while impaired perceptual inhibition was associated with cortical thinning in the right SPL, it was not associated with cortical thickness in either the left VLPFC or SPL. These results suggest a double dissociation between performance on 2 types of inhibitory control tasks and cortical thinning in specific brain areas, previously shown to be uniquely associated with functional activation of each these 2 types of cognitive tasks. (PsycINFO Database Record

Visual Acuity does not Moderate Effect Sizes of Higher-Level Cognitive Tasks

BACKGROUND/STUDY CONTEXT

Declining visual capacities in older adults have been posited as a driving force behind adult age differences in higher-order cognitive functions (e.g., the "common cause" hypothesis of Lindenberger & Baltes, 1994, Psychology and Aging, 9, 339-355). McGowan, Patterson, and Jordan (2013, Experimental Aging Research, 39, 70-79) also found that a surprisingly large number of published cognitive aging studies failed to include adequate measures of visual acuity. However, a recent meta-analysis of three studies (La Fleur and Salthouse, 2014, Psychonomic Bulletin & Review, 21, 1202-1208) failed to find evidence that visual acuity moderated or mediated age differences in higher-level cognitive processes. In order to provide a more extensive test of whether visual acuity moderates age differences in higher-level cognitive processes, we conducted a more extensive meta-analysis of topic.

METHODS

Using results from 456 studies, we calculated effect sizes for the main effect of age across four cognitive domains (attention, executive function, memory, and perception/language) separately for five levels of visual acuity criteria (no criteria, undisclosed criteria, self-reported acuity, 20/80-20/31, and 20/30 or better).

RESULTS

As expected, age had a significant effect on each cognitive domain. However, these age effects did not further differ as a function of visual acuity criteria.

CONCLUSION

The current meta-analytic, cross-sectional results suggest that visual acuity is not significantly related to age group differences in higher-level cognitive performance-thereby replicating La Fleur and Salthouse (2014). Further efforts are needed to determine whether other measures of visual functioning (e.g., contrast sensitivity, luminance) affect age differences in cognitive functioning.

Impaired memory for material related to a problem solved prior to encoding: suppression at learning or interference at recall?

Earlier research by the author revealed that material encoded incidentally in a speeded affective classification task and related to the demands of a divergent problem tends to be recalled worse in participants who solved the problem prior to encoding than in participants in the control, no-problem condition. The aim of the present experiment was to replicate this effect with a new, size-comparison orienting task, and to test for possible mechanisms of impaired recall. Participants either solved a problem before the orienting task or not, and classified each item in this task either once or three times. There was a reliable effect of impaired recall of problem-related items in the repetition condition, but not in the no-repetition condition. Solving the problem did not influence repetition priming for these items. These results support an account that attributes the impaired recall to inhibitory processes at learning and speak against a proactive interference explanation. However, they can be also accommodated by an account that refers to inefficient context cues and competitor interference at retrieval.

Childhood Socioeconomic Status and Onset of Depression among Japanese Older Adults: The JAGES Prospective Cohort Study

OBJECTIVE

Previous investigations on the impact of childhood socioeconomic status (SES) on depression have focused on middle-aged adults in Western countries. It is unknown whether childhood SES has a long-latency effect on the onset of depression among older adults.

DESIGN

Prospective cohort study.

SETTING

Data were from the Japan Gerontological Evaluation Study.

PARTICIPANTS

We analyzed 10,458 individuals aged 65 years and older without depression (Geriatric Depression Scale <5) at baseline in 2010.

MEASUREMENTS

Participants rated their childhood SES at the age of 15 years according to standards at that time. We used binomial regression analyses with log link and with adjustment for known and potential risk factors to evaluate the risk of depression onset by 2013.

RESULTS

Overall, 13.9% of participants newly reported depression in 2013. After adjusting for age and sex, low childhood SES was positively associated with depression onset (adjusted risk ratio [ARR]: 1.44, 95% confidence interval [CI]: 1.23-1.69). The association decreased after adjustment for education (ARR: 1.33; 95% CI: 1.13-1.57). Even after adjustments for adult SES, current disease status, health behaviors, and social relationships, the association remained significant (ARR: 1.27; 95% CI: 1.08-1.50). The link was stronger among the younger old (65-74 years) than the oldest old (≥75 years).

CONCLUSIONS

Low childhood SES, perhaps due to poverty in post-World War II, has a long-latency effect on the onset of depression among older Japanese adults. The impact of childhood SES on depression was weaker among the oldest old, suggesting survival effects for healthy older Japanese people.

Mind Over Memory

A decline in recollection is a hallmark of even healthy aging and is associated with wider impairments in mental control. Older adults have difficulty internally directing thought and action in line with their goals, and often rely more on external cues. To assess the impact this has on memory, emerging brain-imaging and behavioral approaches investigate the operation and effectiveness of goal-directed control before information is retrieved. Current data point to effects of aging at more than one stage in this process, particularly in the face of competing goals. These effects may reflect wider changes in the proactive, self-initiated regulation of thought and action. Understanding them is essential for establishing whether internal “self-cuing” of memory can be improved, and whether—and when—it is best to use environmental support from external cues to maximize memory performance.

Behavioral and EEG Evidence for Auditory Memory Suppression

The neural basis of motivated forgetting using the Think/No-Think (TNT) paradigm is receiving increased attention with a particular focus on the mechanisms that enable memory suppression. However, most TNT studies have been limited to the visual domain. To assess whether and to what extent direct memory suppression extends across sensory modalities, we examined behavioral and electroencephalographic (EEG) effects of auditory TNT in healthy young adults by adapting the TNT paradigm to the auditory modality. Behaviorally, suppression of memory strength was indexed by prolonged response time (RTs) during the retrieval of subsequently remembered No-Think words. We examined task-related EEG activity of both attempted memory retrieval and inhibition of a previously learned target word during the presentation of its paired associate. Event-related EEG responses revealed two main findings: (1) a centralized Think > No-Think positivity during auditory word presentation (from approximately 0-500 ms); and (2) a sustained Think positivity over parietal electrodes beginning at approximately 600 ms reflecting the memory retrieval effect which was significantly reduced for No-Think words. In addition, word-locked theta (4-8 Hz) power was initially greater for No-Think compared to Think during auditory word presentation over fronto-central electrodes. This was followed by a posterior theta increase indexing successful memory retrieval in the Think condition. The observed event-related potential pattern and theta power analysis are similar to that reported in visual TNT studies and support a modality non-specific mechanism for memory inhibition. The EEG data also provide evidence supporting differing roles and time courses of frontal and parietal regions in the flexible control of auditory memory.

Neural Correlates of Direct and Indirect Suppression of Autobiographical Memories

Research indicates that there are two possible mechanisms by which particular target memories can be intentionally forgotten. Direct suppression, which involves the suppression of the unwanted memory directly, and is dependent on a fronto-hippocampal modulatory process, and, memory substitution, which includes directing one's attention to an alternative memory in order to prevent the unwanted memory from coming to mind, and involves engaging the caudal prefrontal cortex (cPFC) and the mid-ventrolateral prefrontal cortex (VLPFC) regions. Research to date, however, has investigated the neural basis of memory suppression of relatively simple information. The aim of the current study was to use fMRI to identify the neural mechanisms associated with the suppression of autobiographical memories. In the present study, 22 participants generated memories in response to a series of cue words. In a second session, participants learnt these cue-memory pairings, and were subsequently presented with a cue word and asked either to recall (think) or to suppress (no-think) the associated memory, or to think of an alternative memory in order to suppress the original memory (memory-substitution). Our findings demonstrated successful forgetting effects in the no-think and memory substitution conditions. Although we found no activation in the dorsolateral prefrontal cortex, there was reduced hippocampal activation during direct suppression. In the memory substitution condition, however, we failed to find increased activation in the cPFC and VLPFC regions. Our findings suggest that the suppression of autobiographical memories may rely on different neural mechanisms to those established for other types of material in memory.

Retrospective Ratings of Emotions: the Effects of Age, Daily Tiredness, and Personality

Remembering the emotions we have experienced in the past is the core of one's unique life-experience. However, there are many factors, both at the state and trait level that can affect the way past feelings are seen. The main aim of the current study was to examine the impact of individual differences on systematic biases in retrospective ratings compared to the momentary experience of basic emotions such as sadness, fear, happiness, and anger. To this end, an experience sampling study across 2 weeks was conducted using a younger and an older age-group; the experience of momentary emotions was assessed on 7 randomly determined occasions per day, the retrospective ratings being collected at the end of each day about that day, as well as at the end of the study about the previous 2 weeks. The results indicated that age and daily tiredness have significant effects on retrospective emotion ratings over a 1-day period (state level), enhancing the retrospective ratings of negative emotions and decreasing the ratings of felt happiness. Whereas personality traits influence the more long-term emotion experience (trait level), with all Big Five personality traits having selective impact on retrospective emotion ratings of fear, sadness, happiness, and anger. Findings provide further evidence about the systematic biases in retrospective emotion ratings, suggesting that, although retrospective ratings are based on momentary experience, daily tiredness and personality traits systematically influence the way in which past feelings are seen.

The representational consequences of intentional forgetting: Impairments to both the probability and fidelity of long-term memory

We investigated whether intentional forgetting impacts only the likelihood of later retrieval from long-term memory or whether it also impacts the fidelity of those representations that are successfully retrieved. We accomplished this by combining an item-method directed forgetting task with a testing procedure and modeling approach inspired by the delayed-estimation paradigm used in the study of visual short-term memory (STM). Abstract or concrete colored images were each followed by a remember (R) or forget (F) instruction and sometimes by a visual probe requiring a speeded detection response (E1-E3). Memory was tested using an old-new (E1-E2) or remember-know-no (E3) recognition task followed by a continuous color judgment task (E2-E3); a final experiment included only the color judgment task (E4). Replicating the existing literature, more "old" or "remember" responses were made to R than F items and RTs to postinstruction visual probes were longer following F than R instructions. Color judgments were more accurate for successfully recognized or recollected R than F items (E2-E3); a mixture model confirmed a decrease to both the probability of retrieving the F items as well as the fidelity of the representation of those F items that were retrieved (E4). We conclude that intentional forgetting is an effortful process that not only reduces the likelihood of successfully encoding an item for later retrieval, but also produces an impoverished memory trace even when those items are retrieved; these findings draw a parallel between the control of memory representations within working and long-term memory.

False memories in Lewy-body disease

Recently, de Boysson, Belleville, Phillips et al. (2011) found that patients with Lewy-body disease (LBD) showed significantly lower rates of false memories than healthy controls, using the Deese-Roediger-McDermott (DRM) experimental procedure. Given that this result could be explained by the practically null rate of true recognition in the LBD group (0.09), we decided to replicate the study by de Boysson et al. (2011), but including a new condition that would maximize the true recognition rate (and analyze its effect on the rate of false memories). Specifically, in a DRM experiment, we manipulated (within subjects) two study and recognition conditions: in the "immediate" condition, both the LBD patients and the control group of healthy older people received a different recognition test after each study list (containing twelve words associated with a non-presented critical word), while in the "delayed" condition (similar to the one in de Boysson et al., 2011), the participants received the entire series of study lists and then took only one recognition test. The results showed that, in both samples, the "immediate" condition produced higher corrected rates of both true and false recognition than the "delayed" condition, although they were both lower in the LBD patients, which shows that these patients are capable of encoding and recognizing the general similitude underlying information (gist memory) in the right conditions.

What Do We Really Know about Cognitive Inhibition? Task Demands and Inhibitory Effects across a Range of Memory and Behavioural Tasks

Our study explores inhibitory control across a range of widely recognised memory and behavioural tasks. Eighty-seven never-depressed participants completed a series of tasks designed to measure inhibitory control in memory and behaviour. Specifically, a variant of the selective retrieval-practice and the Think/No-Think tasks were employed as measures of memory inhibition. The Stroop-Colour Naming and the Go/No-Go tasks were used as measures of behavioural inhibition. Participants completed all 4 tasks. Task presentation order was counterbalanced across 3 separate testing sessions for each participant. Standard inhibitory forgetting effects emerged on both memory tasks but the extent of forgetting across these tasks was not correlated. Furthermore, there was no relationship between memory inhibition tasks and either of the main behavioural inhibition measures. At a time when cognitive inhibition continues to gain acceptance as an explanatory mechanism, our study raises fundamental questions about what we actually know about inhibition and how it is affected by the processing demands of particular inhibitory tasks.

Understanding How Prior Knowledge Influences Memory in Older Adults

Older adults have a harder time than younger adults remembering specific events and experiences (episodic memory), whereas the ability to use one's general knowledge either improves or remains stable over the life span. Our focus is on the sometimes overlooked but critical possibility that this intact general knowledge can facilitate older adults' episodic memory performance. After reviewing literature that shows how prior knowledge can support remembering in aging as well as lead it astray, we consider open questions including whether prior knowledge is used only to fill in the gaps after a memory failure and when older adults might need to be instructed to apply their prior knowledge. Overall, we situate our claims within theories of cognitive aging, arguing that prior knowledge is a key factor in understanding older adults' memory performance, with the potential to serve as a compensatory mechanism.

The Predictive Impact of Biological and Sociocultural Factors on Executive Processing: The Role of Age, Education, and Frequency of Reading and Writing Habits

Although the impact of education and age on executive functions (EF) has been widely studied, the influence of daily cognitive stimulation on EF has not been sufficiently investigated. Therefore, the aim of the present study was to evaluate whether the age, education, and frequency of reading and writing habits (FRWH) of healthy adults could predict their performance on measures of inhibition and cognitive flexibility. Inhibition speed, inhibitory control, and set shifting were assessed using speed, accuracy, and discrepancy scores on the Trail-Making Test (TMT) and Hayling Test. Demographic characteristics and the FRWH were assessed using specialized questionnaires. Regression analyses showed that age and the FRWH predicted speed and accuracy on the TMT. The FRWH predicted both speed and accuracy on the Hayling Test, for which speed and accuracy scores were also partly explained by age and education, respectively. Surprisingly, only the FRWH was associated with Hayling Test discrepancy scores, considered one of the purest EF measures. This highlights the importance of regular cognitive stimulation over the number of years of formal education on EF tasks. Further studies are required to investigate the role of the FRWH so as to better comprehend its relationship with EF and general cognition.

Cue-independent forgetting by intentional suppression - Evidence for inhibition as the mechanism of intentional forgetting

People are able to intentionally forget unwanted memories through voluntary suppression, as revealed by the Think/No-think (TNT) paradigm. However, the nature of intentional forgetting is controversial. Findings that forgetting is independent of retrieval cues suggest that inhibitory control underlies intentional forgetting, but this result is also in line with an interference account. To resolve this controversy, we have directly contrasted the cue-independent characteristic of suppression versus interference. A double-cue paradigm was used, in which two different cues were associated with the same target during initial memory formation. Only one cue-target association received further interference/suppression training. In the test phase, when both cues were used to retrieve the target, we found that interference caused memory impairment that was restricted to the trained cue-target association, while suppression induced forgetting that generalized to the independent cue-target association. Therefore, the effect of suppression differs from that of interference. The cue-independent forgetting by voluntary suppression indicates that the target memory itself is inhibited, providing evidence that the underlying mechanism of suppression-induced forgetting is inhibitory control.

Older adults can suppress unwanted memories when given an appropriate strategy

Memory suppression refers to the ability to exclude distracting memories from conscious awareness, and this ability can be assessed with the think/no-think paradigm. Recent research with older adults has provided evidence suggesting both intact and deficient memory suppression. The present studies seek to understand the conditions contributing to older adults' ability to suppress memories voluntarily. We report 2 experiments indicating that the specificity of the think/no-think task instructions contributes to older adults' suppression success: When older adults receive open-ended instructions that require them to develop a retrieval suppression strategy on their own, they show diminished memory suppression compared with younger adults. Conversely, when older adults receive focused instructions directing them to a strategy thought to better isolate inhibitory control, they show suppression-induced forgetting similar to that exhibited by younger adults. Younger adults demonstrate memory suppression regardless of the specificity of the instructions given, suggesting that the ability to select a successful suppression strategy spontaneously may be compromised in older adults. If so, this deficit may be associated with diminished control over unwanted memories in naturalistic settings if impeded strategy development reduces the successful deployment of inhibitory control.

The impact of intermediate-term alcohol abstinence on memory retrieval and suppression

Background: The nature of episodic memory deficit in intermediate-term abstinence from alcohol in alcohol dependence (AD) is not yet clarified. Deficits in inhibitory control are commonly reported in substance use disorders. However, much less is known about cognitive control suppressing interference from memory. The Think/No-think (TNT) paradigm is a well established method to investigate inhibition of associative memory retrieval.

Methods: Thirty-six unmedicated patients with AD and 36 healthy controls (HCs) performed the TNT task. Thirty image–word pairs were trained up to a predefined accuracy level. Cued recall was examined in three conditions: Think (T) for items instructed to-be-remembered, No-think (NT) assessing the ability to suppress retrieval and Baseline (B) for general relational memory. Premorbid IQ, clinical variables and impulsivity measures were quantified.

Results: AD patients had a significantly increased demand for training. Baseline memory abilities and effect of practice on retrieval were not markedly different between the groups. We found a significant main effect of group (HC vs. AD) × condition (B, T, and NT) and a significant difference in mean NT–B scores for the two groups.

Discussion: AD and HC groups did not differ essentially in their baseline memory abilities. Also, the instruction to focus on retrieval improved episodic memory performance in both groups. Crucially, control participants were able to suppress relational words in the NT condition supporting the critical effect of cognitive control processes over inhibition of retrieval. In contrast to this, the ability of AD patients to suppress retrieval was found to be impaired.

Forgiving You Is Hard, but Forgetting Seems Easy

Forgiveness is considered to play a key role in the maintenance of social relationships, the avoidance of unnecessary conflict, and the ability to move forward with one’s life. But why is it that some people find it easier to forgive and forget than others? In the current study, we explored the supposed relationship between forgiveness and forgetting. In an initial session, 30 participants imagined that they were the victim in a series of hypothetical incidents and indicated whether or not they would forgive the transgressor. Following a standard think/no-think procedure, in which participants were trained to think or not to think about some of these incidents, more forgetting was observed for incidents that had been forgiven following no-think instructions compared with either think or baseline instructions. In contrast, no such forgetting effects emerged for incidents that had not previously been forgiven. These findings have implications for goal-directed forgetting and the relationship between forgiveness and memory.

Inhibitory effects of thought substitution in the think/no-think task: evidence from independent cues

When people try not to think about a certain item, they can accomplish this goal by using a thought substitution strategy and think about something else. Research conducted with the think/no-think (TNT) paradigm indicates that such strategy leads subsequently to forgetting the information participants tried not to think about. The present study pursued two goals. First, it investigated the mechanism of forgetting due to thought substitution, contrasting the hypothesis by which forgetting is due to blocking caused by substitutes with the hypothesis that forgetting is due to inhibition (using an independent cue methodology). Second, a boundary condition for forgetting due to thought substitution was examined by creating conditions under which the generation of appropriate substitutes would be impaired. In two experiments, participants completed a TNT task under thought substitution instructions in which either words or pseudo-words were used as original cues and memory was assessed with original and independent cues. The results revealed forgetting in both original and independent cue tests, supporting the inhibitory account of thought substitution, but only when cues were words, and not when they were non-words, pointing to the ineffectiveness of a thought substitution strategy when original cues lack semantic content.

Neural mechanisms of motivated forgetting

•

Motivated forgetting of unwanted memories shapes what we retain of our personal past.

•

Motivated forgetting is achieved in part by inhibitory control over encoding or retrieval.

•

Prefrontal cortex reduces hippocampal and cortical activity to suppress memories.

•

Electrophysiological activity during motivated forgetting implicates active inhibition.

•

A neurobiological model of memory control can inform disordered control over memory.

Not all memories are equally welcome in awareness. People limit the time they spend thinking about unpleasant experiences, a process that begins during encoding, but that continues when cues later remind someone of the memory. Here, we review the emerging behavioural and neuroimaging evidence that suppressing awareness of an unwelcome memory, at encoding or retrieval, is achieved by inhibitory control processes mediated by the lateral prefrontal cortex. These mechanisms interact with neural structures that represent experiences in memory, disrupting traces that support retention. Thus, mechanisms engaged to regulate momentary awareness introduce lasting biases in which experiences remain accessible. We argue that theories of forgetting that neglect the motivated control of awareness omit a powerful force shaping the retention of our past.