Everyday amnesia: Residual memory for high confidence misses and implications for decision models of recognition.

Despite studying a list of items only minutes earlier, when reencountered in a recognition memory test, undergraduate participants often say with total confidence that they have not studied some of the items before. Such high confidence miss (HCM) responses have been taken as evidence of rapid and complete forgetting and of everyday amnesia (Roediger & Tekin, 2020). We investigated (a) if memory for HCMs is completely lost or whether a residual memory effect exists and (b) whether dominant decision models predict the effect. Participants studied faces (Experiments 1a, 2, and 3) or words (Experiment 1b), then completed a single-item recognition memory task, followed by either (a) a two-alternative forced-choice recognition task, in which the studied and nonstudied alternatives on each trial were matched for their previous old/new decision and confidence rating (Experiments 1 and 2) or (b) a second single-item recognition task in which the targets and foils were HCMs and high confidence correct rejections, respectively (Experiment 3). In each experiment, participants reliably distinguished HCMs from high-confidence correct rejections. The unequal variance signal detection and dual-process signal detection models were fit to the single-item recognition data, and the parameter estimates were used to predict the memory effect for HCMs. The dual-process signal detection model predicted the residual memory effect (as did another popular model, the mixture signal detection theory model). However, the unequal variance signal detection model incorrectly predicted a negative, or no, effect, invalidating this model. The residual memory effect for HCMs demonstrates that everyday amnesia is not associated with complete memory loss and distinguishes between decision models. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Does variability in recognition memory scale with mean memory strength or encoding variability in the UVSD model?

The unequal variance signal detection (UVSD) model of recognition memory assumes that the variance of old item memory strength (σo) is typically greater than that of new items. It has been suggested that this old item variance effect can be explained by the encoding variability hypothesis. However, Spanton and Berry (2020) failed to find evidence for this account, suggesting that σo may simply scale with mean memory strength (d) in the UVSD model. Experiments 1 and 2 examined the effects of encoding variability and strength scaling on old item variance by creating conditions in which mean memory strength and variability in item characteristics was either low or high in 2 × 2 factorial designs. In Experiment 1, overall strength determined estimates of σo, with no effect of item characteristic variability. The same effect of overall strength was found in Experiment 2; there was also a significant effect of item characteristic variability, although this manipulation also had some effect on d and was therefore partially confounded. Experiment 3 similarly found a simultaneous increase in old item variance and memory strength in a design using mixed item characteristic variability conditions in a single-study/test block. We conclude that old item variance increases with mean memory strength in the UVSD model, with uncertainty about the effects of encoding variability, and that future explanations of the old item variance effect should bear this in mind.

Explaining the association between repetition priming and source memory: No evidence for a contribution of recognition or fluency.

In a conjoint memory task (measuring repetition priming, recognition memory, and source memory), items recognised as previously studied and receiving correct source decisions also tend to show a greater magnitude of the repetition priming effect. These associations have been explained as arising from a single memory system or signal, rather than multiple distinct ones. In the present work, we examine whether the association between priming and source memory can alternatively be explained as being driven by recognition or fluency. We first reproduced the basic priming-source association (Experiment 1). In Experiments 2 and 3, we found that the association persisted even when the task was modified so that overt and covert recognition judgements were precluded. In Experiment 4, the association was again present even though fluency (as measured by identification response time) could not influence the source decision, although the association was notably weaker. These findings suggest that the association between priming and source memory is not attributable to a contribution of recognition or fluency; instead, the findings are consistent with a single-system account in which a common memory signal drives responding.

Aging Predicts Decline in Explicit and Implicit Memory: A Life-Span Study.

Explicit memory declines with age, but age effects on implicit memory are debated. This issue is important because if implicit memory is age invariant, it may support effective interventions in individuals experiencing memory decline. In this study, we overcame several methodological issues in past research to clarify age effects on implicit memory (priming) and their relationship to explicit memory (recognition, source memory). We (a) recruited a large life-span sample of participants (N = 1,072) during a residency at the Science Museum in London, (b) employed an implicit task that was unaffected by explicit contamination, and (c) systematically manipulated attention and depth of processing to assess their contribution to age effects. Participants witnessed a succession of overlapping colored objects, attending to one color stream and ignoring the other, and identified masked objects at test before judging whether they were previously attended, unattended, or new. Age significantly predicted decline in both explicit and implicit memory for attended items.

The unequal variance signal-detection model of recognition memory: Investigating the encoding variability hypothesis.

Despite the unequal variance signal-detection (UVSD) model's prominence as a model of recognition memory, a psychological explanation for the unequal variance assumption has yet to be verified. According to the encoding variability hypothesis, old item memory strength variance (σo) is greater than that of new items because items are incremented by variable, rather than fixed, amounts of strength at encoding. Conditions that increase encoding variability should therefore result in greater estimates of σo. We conducted three experiments to test this prediction. In Experiment 1, encoding variability was manipulated by presenting items for a fixed or variable (normally distributed) duration at study. In Experiment 2, we used an attentional manipulation whereby participants studied items while performing an auditory one-back task in which distractors were presented at fixed or variable intervals. In Experiment 3, participants studied stimuli with either high or low variance in word frequency. Across experiments, estimates of σo were unaffected by our attempts to manipulate encoding variability, even though the manipulations weakly affected subsequent recognition. Instead, estimates of σo tended to be positively correlated with estimates of the mean difference in strength between new and studied items (d), as might be expected if σo generally scales with d. Our results show that it is surprisingly hard to successfully manipulate encoding variability, and they provide a signpost for others seeking to test the encoding variability hypothesis.

A single system account of enhanced recognition memory in synaesthesia.

Researchers often adjudicate between models of memory according to the models' ability to explain impaired patterns of performance (e.g., in amnesia). In contrast, evidence from special groups with enhanced memory is very rarely considered. Here, we explored how people with unusual perceptual experiences (synaesthesia) perform on various measures of memory and test how computational models of memory may account for their enhanced performance. We contrasted direct and indirect measures of memory (i.e., recognition memory, repetition priming, and fluency) in grapheme-colour synaesthetes and controls using a continuous identification with recognition (CID-R) paradigm. Synaesthetes outperformed controls on recognition memory and showed a different reaction-time pattern for identification. The data were most parsimoniously accounted for by a single-system computational model of the relationship between recognition and identification. Overall, the findings speak in favour of enhanced processing as an explanation for the memory advantage in synaesthesia. In general, our results show how synaesthesia can be used as an effective tool to study how individual differences in perception affect cognitive functions.

Review of concrete biodeterioration in relation to nuclear waste.

Storage of radioactive waste in concrete structures is a means of containing wastes and related radionuclides generated from nuclear operations in many countries. Previous efforts related to microbial impacts on concrete structures that are used to contain radioactive waste showed that microbial activity can play a significant role in the process of concrete degradation and ultimately structural deterioration. This literature review examines the research in this field and is focused on specific parameters that are applicable to modeling and prediction of the fate of concrete structures used to store or dispose of radioactive waste. Rates of concrete biodegradation vary with the environmental conditions, illustrating a need to understand the bioavailability of key compounds involved in microbial activity. Specific parameters require pH and osmotic pressure to be within a certain range to allow for microbial growth as well as the availability and abundance of energy sources such as components involved in sulfur, iron and nitrogen oxidation. Carbon flow and availability are also factors to consider in predicting concrete biodegradation. The microbial contribution to degradation of the concrete structures containing radioactive waste is a constant possibility. The rate and degree of concrete biodegradation is dependent on numerous physical, chemical and biological parameters. Parameters to focus on for modeling activities and possible options for mitigation that would minimize concrete biodegradation are discussed and include key conditions that drive microbial activity on concrete surfaces.

Good Liars Are Neither 'Dark' Nor Self-Deceptive.

Deception is a central component of the personality 'Dark Triad' (Machiavellianism, Psychopathy and Narcissism). However, whether individuals exhibiting high scores on Dark Triad measures have a heightened deceptive ability has received little experimental attention. The present study tested whether the ability to lie effectively, and to detect lies told by others, was related to Dark Triad, Lie Acceptability, or Self-Deceptive measures of personality using an interactive group-based deception task. At a group level, lie detection accuracy was correlated with the ability to deceive others-replicating previous work. No evidence was found to suggest that Dark Triad traits confer any advantage either to deceive others, or to detect deception in others. Participants who considered lying to be more acceptable were more skilled at lying, while self-deceptive individuals were generally less credible and less confident when lying. Results are interpreted within a framework in which repeated practice results in enhanced deceptive ability.

A single-system model predicts recognition memory and repetition priming in amnesia.

We challenge the claim that there are distinct neural systems for explicit and implicit memory by demonstrating that a formal single-system model predicts the pattern of recognition memory (explicit) and repetition priming (implicit) in amnesia. In the current investigation, human participants with amnesia categorized pictures of objects at study and then, at test, identified fragmented versions of studied (old) and nonstudied (new) objects (providing a measure of priming), and made a recognition memory judgment (old vs new) for each object. Numerous results in the amnesic patients were predicted in advance by the single-system model, as follows: (1) deficits in recognition memory and priming were evident relative to a control group; (2) items judged as old were identified at greater levels of fragmentation than items judged new, regardless of whether the items were actually old or new; and (3) the magnitude of the priming effect (the identification advantage for old vs new items) overall was greater than that of items judged new. Model evidence measures also favored the single-system model over two formal multiple-systems models. The findings support the single-system model, which explains the pattern of recognition and priming in amnesia primarily as a reduction in the strength of a single dimension of memory strength, rather than a selective explicit memory system deficit.

Deceptively simple The "deception-general" ability and the need to put the liar under the spotlight.

This Focused Review expands upon our original paper (You can't kid a kidder": Interaction between production and detection of deception in an interactive deception task. Frontiers in Human Neuroscience, 6:87). In that paper we introduced a new socially interactive, laboratory-based task, the Deceptive Interaction Task (DeceIT), and used it to measure individuals' ability to lie, their ability to detect the lies of others, and potential individual difference measures contributing to these abilities. We showed that the two skills were correlated; better liars made better lie detectors (a "deception general" ability) and this ability seemed to be independent of cognitive (IQ) and emotional (EQ) intelligence. Here, following the Focused Review format, we outline the method and results of the original paper and comment more on the value of lab-based experimental studies of deception, which have attracted criticism in recent years. While acknowledging that experimental paradigms may fail to recreate the full complexity and potential seriousness of real-world deceptive behavior, we suggest that lab-based deception paradigms can offer valuable insight into ecologically-valid deceptive behavior. The use of the DeceIT procedure enabled deception to be studied in an interactive setting, with motivated participants, and importantly allowed the study of both the liar and the lie detector within the same deceptive interaction. It is our thesis that by addressing deception more holistically-by bringing the liar into the "spotlight" which is typically trained exclusively on the lie detector-we may further enhance our understanding of deception.

Age effects on explicit and implicit memory.

It is well-documented that explicit memory (e.g., recognition) declines with age. In contrast, many argue that implicit memory (e.g., priming) is preserved in healthy aging. For example, priming on tasks such as perceptual identification is often not statistically different in groups of young and older adults. Such observations are commonly taken as evidence for distinct explicit and implicit learning/memory systems. In this article we discuss several lines of evidence that challenge this view. We describe how patterns of differential age-related decline may arise from differences in the ways in which the two forms of memory are commonly measured, and review recent research suggesting that under improved measurement methods, implicit memory is not age-invariant. Formal computational models are of considerable utility in revealing the nature of underlying systems. We report the results of applying single and multiple-systems models to data on age effects in implicit and explicit memory. Model comparison clearly favors the single-system view. Implications for the memory systems debate are discussed.

An effect of age on implicit memory that is not due to explicit contamination: implications for single and multiple-systems theories.

Recognition memory is typically weaker in healthy older relative to young adults, while performance on implicit tests (e.g., repetition priming) is often comparable between groups. Such observations are commonly taken as evidence for independent explicit and implicit memory systems. On a picture version of the continuous identification with recognition (CID-R) task, we found a reliable age-related reduction in recognition memory, while the age effect on priming did not reach statistical significance (Experiment 1). This pattern was consistent with the predictions of a formal single-system model. Experiment 2 replicated these observations using separate priming (continuous identification; CID) and recognition phases, while a combined data analysis revealed a significant effect of age on priming. In Experiment 3, we provide evidence that priming in this task is unaffected by explicit processing, and we conclude that the age difference in priming is unlikely to have been driven by differences in explicit processing between groups of young and older adults ("explicit contamination"). The results support the view that explicit and implicit expressions of memory are driven by a single underlying memory system.

EPS Mid-Career Award 2011. Are there multiple memory systems? Tests of models of implicit and explicit memory.

This article reviews recent work aimed at developing a new framework, based on signal detection theory, for understanding the relationship between explicit (e.g., recognition) and implicit (e.g., priming) memory. Within this framework, different assumptions about sources of memorial evidence can be framed. Application to experimental results provides robust evidence for a single-system model in preference to multiple-systems models. This evidence comes from several sources including studies of the effects of amnesia and ageing on explicit and implicit memory. The framework allows a range of concepts in current memory research, such as familiarity, recollection, fluency, and source memory, to be linked to implicit memory. More generally, this work emphasizes the value of modern computational modelling techniques in the study of learning and memory.

"You can't kid a kidder": association between production and detection of deception in an interactive deception task.

Both the ability to deceive others, and the ability to detect deception, has long been proposed to confer an evolutionary advantage. Deception detection has been studied extensively, and the finding that typical individuals fare little better than chance in detecting deception is one of the more robust in the behavioral sciences. Surprisingly, little research has examined individual differences in lie production ability. As a consequence, as far as we are aware, no previous study has investigated whether there exists an association between the ability to lie successfully and the ability to detect lies. Furthermore, only a minority of studies have examined deception as it naturally occurs; in a social, interactive setting. The present study, therefore, explored the relationship between these two facets of deceptive behavior by employing a novel competitive interactive deception task (DeceIT). For the first time, signal detection theory (SDT) was used to measure performance in both the detection and production of deception. A significant relationship was found between the deception-related abilities; those who could accurately detect a lie were able to produce statements that others found difficult to classify as deceptive or truthful. Furthermore, neither ability was related to measures of intelligence or emotional ability. We, therefore, suggest the existence of an underlying deception-general ability that varies across individuals.

Models of recognition, repetition priming, and fluency: exploring a new framework.

We present a new modeling framework for recognition memory and repetition priming based on signal detection theory. We use this framework to specify and test the predictions of 4 models: (a) a single-system (SS) model, in which one continuous memory signal drives recognition and priming; (b) a multiple-systems-1 (MS1) model, in which completely independent memory signals (such as explicit and implicit memory) drive recognition and priming; (c) a multiple-systems-2 (MS2) model, in which there are also 2 memory signals, but some degree of dependence is allowed between these 2 signals (and this model subsumes the SS and MS1 models as special cases); and (d) a dual-process signal detection (DPSD1) model, 1 possible extension of a dual-process theory of recognition (Yonelinas, 1994) to priming, in which a signal detection model is augmented by an independent recollection process. The predictions of the models are tested in a continuous-identification-with-recognition paradigm in both normal adults (Experiments 1-3) and amnesic individuals (using data from Conroy, Hopkins, & Squire, 2005). The SS model predicted numerous results in advance. These were not predicted by the MS1 model, though could be accommodated by the more flexible MS2 model. Importantly, measures of overall model fit favored the SS model over the others. These results illustrate a new, formal approach to testing theories of explicit and implicit memory.

Can "pure" implicit memory be isolated? A test of a single-system model of recognition and repetition priming.

Implicit memory is widely regarded as an unconscious form of memory. However, evidence for what is arguably a defining characteristic of implicit memory-that its contents are not accessible to awareness-has remained elusive. Such a finding of "pure" implicit memory would constitute evidence against a single-system model of recognition and priming that predicts that priming will not occur in the (true) absence of recognition. In three experiments, using a rapid serial visual presentation procedure at encoding, we tested this prediction by attempting to replicate some previous studies that claimed to obtain pure implicit memory. We found no evidence of priming in the absence of recognition; instead, priming and recognition were associated across experiments: when priming was absent, recognition was also absent (Experiments 1 and 2), and when priming was reliably greater than chance, recognition was similarly greater than chance (Experiment 3). The results are consistent with the prediction of a single-system model, which was fit to the data from all the experiments. The results are also consistent with the notion that the memory driving priming is accessible to awareness.

Biventricular adaptation to volume overload in mice with aortic regurgitation.

BACKGROUND: Aortic valve regurgitation is usually caused by impaired coaptation of the aortic valve cusps during diastole. Hypercholesterolemia produces aortic valve lipid deposition, fibrosis, and calcification in both mice and humans, which could impair coaptation of cusps. However, a link between hypercholesterolemia and aortic regurgitation has not been established in either species. The purpose of this study was to ascertain the prevalence of aortic regurgitation in hypercholesterolemic mice and to determine its impact on the left and right ventricles. METHODS AND RESULTS: Eighty Ldlr-/-/Apob100/100/Mttpfl/fl/Mx1Cre+/+ ("Reversa") hypercholesterolemic mice and 40 control mice were screened for aortic regurgitation (AR) with magnetic resonance imaging at age 7.5 months. The prevalence of AR was 40% in Reversa mice, with moderate or severe regurgitation (AR+) in 19% of mice. In control mice, AR prevalence was 13% (p = 0.004 vs. Reversa), and was invariably trace or mild in severity. In-depth evaluation of cardiac response to volume overload was performed in 12 AR-positive and 12 AR-negative Reversa mice. Regurgitant fraction was 0.34 +/- 0.04 in AR-positive vs. 0.02 +/- 0.01 in AR-negative (mean +/- SE; p < 0.001). AR-positive mice had significantly increased left ventricular end-diastolic volume and mass and reduced ejection fraction in both ventricles. When left ventricular ejection fraction fell below 0.60 in AR-positive (n = 7) mice, remodeling occurred and right ventricular systolic function progressively worsened. CONCLUSION: Hypercholesterolemia causes aortic valve regurgitation with moderate prevalence in mice. When present, aortic valve regurgitation causes volume overload and pathological remodeling of both ventricles.

Lowering plasma cholesterol levels halts progression of aortic valve disease in mice.

BACKGROUND: Treatment of hyperlipidemia produces functional and structural improvements in atherosclerotic vessels. However, the effects of treating hyperlipidemia on the structure and function of the aortic valve have been controversial, and any effects could be confounded by pleiotropic effects of hypolipidemic treatment. The goal of this study was to determine whether reducing elevated plasma lipid levels with a "genetic switch" in Reversa mice (Ldlr-/-/Apob(100/100)/Mttp(fl/fl)/Mx1-Cre+/+) reduces oxidative stress, reduces pro-osteogenic signaling, and retards the progression of aortic valve disease. METHODS AND RESULTS: After 6 months of hypercholesterolemia, Reversa mice exhibited increases in superoxide, lipid deposition, myofibroblast activation, calcium deposition, and pro-osteogenic protein expression in the aortic valve. Maximum aortic valve cusp separation, as judged by echocardiography, was not altered. During an additional 6 months of hypercholesterolemia, superoxide levels, valvular lipid deposition, and myofibroblast activation remained elevated. Furthermore, calcium deposition and pro-osteogenic gene expression became more pronounced, and the aortic cusp separation decreased from 0.85+/-0.04 to 0.70+/-0.04 mm (mean+/-SE; P<0.05). Rapid normalization of cholesterol levels at 6 months of age (by inducing expression of Cre recombinase) normalized aortic valve superoxide levels, decreased myofibroblast activation, reduced valvular calcium burden, suppressed pro-osteogenic signaling cascades, and prevented reductions in aortic valve cusp separation. CONCLUSIONS: Collectively, these data indicate that reducing plasma lipid levels by genetic inactivation of the mttp gene in hypercholesterolemic mice with early aortic valve disease normalizes oxidative stress, reduces pro-osteogenic signaling, and halts the progression of aortic valve stenosis.

Effects of deep sedation or general anesthesia on cardiac function in mice undergoing cardiovascular magnetic resonance.

BACKGROUND: Genetically engineered mouse models of human cardiovascular disease provide an opportunity to understand critical pathophysiological mechanisms. Cardiovascular magnetic resonance (CMR) provides precise reproducible assessment of cardiac structure and function, but, in contrast to echocardiography, requires that the animal be immobilized during image acquisition. General anesthetic regimens yield satisfactory images, but have the potential to significantly perturb cardiac function. The purpose of this study was to assess the effects of general anesthesia and a new deep sedation regimen, respectively, on cardiac function in mice as determined by CMR, and to compare them to results obtained in mildly sedated conscious mice by echocardiography. RESULTS: In 6 mildly sedated normal conscious mice assessed by echo, heart rate was 615 +/- 25 min-1 (mean +/- SE) and left ventricular ejection fraction (LVEF) was 0.94 +/- 0.01. In the CMR studies of normal mice, heart rate was slightly lower during deep sedation with morphine/midazolam (583 +/- 30 min-1), but the difference was not statistically significant. General anesthesia with 1% inhaled isoflurane significantly depressed heart rate (468 +/- 7 min-1, p < 0.05 vs. conscious sedation). In 6 additional mice with ischemic LV failure, trends in heart rate were similar, but not statistically significant. In normal mice, deep sedation depressed LVEF (0.79 +/- 0.04, p < 0.05 compared to light sedation), but to a significantly lesser extent than general anesthesia (0.60 +/- 0.04, p < 0.05 vs. deep sedation). In mice with ischemic LV failure, ejection fraction measurements were comparable when performed during light sedation, deep sedation, and general anesthesia, respectively. Contrast-to-noise ratios were similar during deep sedation and during general anesthesia, indicating comparable image quality. Left ventricular mass measurements made by CMR during deep sedation were nearly identical to those made during general anesthesia (r2 = 0.99, mean absolute difference < 4%), indicating equivalent quantitative accuracy obtained with the two methods. The imaging procedures were well-tolerated in all mice. CONCLUSION: In mice with normal cardiac function, CMR during deep sedation causes significantly less depression of heart rate and ejection fraction than imaging during general anesthesia with isoflurane. In mice with heart failure, the sedation/anesthesia regimen had no clear impact on cardiac function. Deep sedation and general anesthesia produced CMR with comparable image quality and quantitative accuracy.

A unitary signal-detection model of implicit and explicit memory.

Do dissociations imply independent systems? In the memory field, the view that there are independent implicit and explicit memory systems has been predominantly supported by dissociation evidence. Here, we argue that many of these dissociations do not necessarily imply distinct memory systems. We review recent work with a single-system computational model that extends signal-detection theory (SDT) to implicit memory. SDT has had a major influence on research in a variety of domains. The current work shows that it can be broadened even further in its range of application. Indeed, the single-system model that we present does surprisingly well in accounting for some key dissociations that have been taken as evidence for independent implicit and explicit memory systems.