Memory strength and the decision process in recognition memory

Retrieving effectively from source memory: Evidence for differentiation and local matching processes

The ability to distinguish between different explanations of human memory abilities continues to be the subject of many ongoing theoretical debates. These debates attempt to account for a growing corpus of empirical phenomena in item-memory judgments, which include the list strength effect, the strength-based mirror effect, and output interference. One of the main theoretical contenders is the Retrieving Effectively from Memory (REM) model. We show that REM, in its current form, has difficulties in accounting for source-memory judgments - a situation that calls for its revision. We propose an extended REM model that assumes a local-matching process for source judgments alongside source differentiation. We report a first evaluation of this model's predictions using three experiments in which we manipulated the relative source-memory strength of different lists of items. Analogous to item-memory judgments, we observed a null list strength effect and a strength-based mirror effect in the case of source memory. In a second evaluation, which relied on a novel experiment alongside two previously published datasets, we evaluated the model's predictions regarding the manifestation of output interference in item and lack of it in source memory judgments. Our results showed output interference severely affecting the accuracy of item-memory judgments but having a null or negligible impact when it comes to source-memory judgments. Altogether, these results support REM's core notion of differentiation (for both item and source information) as well as the concept of local matching proposed by the present extension.

Response-locked theta dissociations reveal potential feedback signal following successful retrieval

Successful memory retrieval relies on memory processes to access an internal representation and decision processes to evaluate and respond to the accessed representation, both of which are supported by fluctuations in theta (4-8Hz) activity. However, the extent to which decision making processes are engaged following a memory response is unclear. Here, we recorded scalp electroencephalography (EEG) while human participants performed a recognition memory task. We focused on response-locked data, allowing us to investigate the processes that occur prior to and following a memory response. We replicate previous work and find that prior to a memory response theta power is greater for identification of previously studied items (hits) relative to rejection of novel lures (correct rejections; CRs). Following the memory response, the theta power dissociation 'flips' whereby theta power is greater for CRs relative to hits. We find that the post-response 'flip' is more robust for hits that are committed quickly, potentially reflecting a positive feedback signal for strongly remembered experiences. Our findings suggest that there are potentially distinct processes occurring before and after a memory response that are modulated by successful memory retrieval.

Face masks are less effective than sunglasses in masking face identity

The effect of covering faces on face identification is recently garnering interest amid the COVID-19 pandemic. Here, we investigated how face identification performance was affected by two types of face disguise: sunglasses and face masks. Observers studied a series of faces; then judged whether a series of test faces, comprising studied and novel faces, had been studied before or not. Face stimuli were presented either without coverings (full faces), wearing sunglasses covering the upper region (eyes, eyebrows), or wearing surgical masks covering the lower region (nose, mouth, chin). We found that sunglasses led to larger reductions in sensitivity (d') to face identity than face masks did, while both disguises increased the tendency to report faces as studied before, a bias that was absent for full faces. In addition, faces disguised during either study or test only (i.e. study disguised faces, test with full faces; and vice versa) led to further reductions in sensitivity from both studying and testing with disguised faces, suggesting that congruence between study and test is crucial for memory retrieval. These findings implied that the upper region of the face, including the eye-region features, is more diagnostic for holistic face-identity processing than the lower face region.

Age Effects on Old/New Recognition Memory Involving Abstract Figures and Non-words

Age-related memory problems posit a growing concern in our society. This study investigated the impact of age and memory strength on recognition memory of pre-experimentally unfamiliar abstract figures and non-words. We applied a three-phase old/new recognition memory paradigm and manipulated memory strength as a function of the Levels of Processing (deep vs. shallow) and repetition. Older adults relative to the young showed impairment in the correct identification of new items. As indicated by the lower discriminability indexes, the older adults also had difficulties discriminating the strongly (drawn/semantically processed) and the weakly (studied) embedded abstract figures but not the non-words. Age-related differences in reaction times were only evident with the abstract figures. Finally, our results revealed that the recognition performance was equally affected by memory strength in both age groups. The current findings agree with previous research on age-related impairment in new item recognition, which can be attributed to misrecollection and decreased sensitivity to novelty in the older adults than the young. The detected age effects on the discriminability of the drawn and studied abstract figures agree with the age-related impairment in the perceptual encoding hypothesis and support the notion related to the need for environmental support to reduce age effects. The lack of age effects with the non-words indicates that age effects on discriminability are stimulus-dependent. The current results support the notion that recognition memory in aging is only impaired under certain conditions and depends on the stimuli used.

The antimuscarinic agent biperiden selectively impairs recognition of abstract figures without affecting the processing of non-words

OBJECTIVES

The present study investigated the effects of biperiden, a muscarinic type 1 antagonist, on the recognition performance of pre-experimentally unfamiliar abstract figures and non-words in healthy young volunteers. The aim was to examine whether 4 mg biperiden could model the recognition memory impairment seen in healthy aging.

METHODS

A double-blind, placebo-controlled, two-way crossover study was conducted. We used a three-phase (deep memorization, shallow memorization, and recognition) old/new discrimination paradigm in which memory strength was manipulated. Strong memories were induced by deep encoding and repetition. Deep encoding was encouraged by redrawing the abstract figures and mentioning existing rhyme words for the non-words (semantic processing). Weak memories were created by merely instructing the participants to study the stimuli (shallow memorization).

RESULTS

Biperiden impaired recognition accuracy and prolonged reaction times of the drawn and the studied abstract figures. However, participants were biased towards "old" responses in the placebo condition. The recognition of the new abstract figures was unaffected by the drug. Biperiden did not affect the recognition of the non-words.

CONCLUSIONS

Although biperiden may model age-related deficits in episodic memory, the current findings indicate that biperiden does not mimic age-related deficits in recognition performance.

Test position effects on hit and false alarm rates in recognition memory for paintings and words

When old/new recognition memory is tested with equal numbers of studied and nonstudied items and no rewards or instructions that favour one response over the other, there is no obvious reason for response bias. In line with this, Canadian undergraduates have shown, on average, a neutral response bias when we tested them on recognition of common English words. By contrast, most subjects we have tested on recognition of richly detailed images have shown a conservative bias: they more often erred by missing a studied image than by judging a nonstudied image as studied. Here, in an effort to better understand these materials-based bias effects (MBBEs), we examined changes in hit and false alarm (FA) rates (and in sensitivity and bias) from the first to fourth quartile of a recognition memory test in eight experiments in which undergraduates studied words and/or images of paintings. Response bias for images tended to increase across quartiles, whereas bias for words showed no consistent pattern across quartiles. This pattern could be described as an increase in the MBBE over the course of the test, but the underlying patterns for hits and FAs are not easily reconciled with this interpretation. Hit rates decreased over the course of the test for both materials types, with that decline tending to be steeper for images than words. For words, FA rates tended to increase across quartiles, whereas for paintings FA rates did not increase across quartiles. We discuss implications of these findings for theoretical accounts of the MBBE.

EEG Correlates of Old/New Discrimination Performance Involving Abstract Figures and Non-Words

The processing of pre-experimentally unfamiliar stimuli such as abstract figures and non-words is poorly understood. Here, we considered the role of memory strength in the discrimination process of such stimuli using a three-phase old/new recognition memory paradigm. Memory strength was manipulated as a function of the levels of processing (deep vs. shallow) and repetition. Behavioral results were matched to brain responses using EEG. We found that correct identification of the new abstract figures and non-words was superior to old item recognition when they were merely studied without repetition, but not when they were semantically processed or drawn. EEG results indicated that successful new item identification was marked by a combination of the absence of familiarity (N400) and recollection (P600) for the studied figures. For both the abstract figures and the non-words, the parietal P600 was found to differentiate between the old and new items (late old/new effects). The present study extends current knowledge on the processing of pre-experimentally unfamiliar figurative and verbal stimuli by showing that their discrimination depends on experimentally induced memory strength and that the underlying brain processes differ. Nevertheless, the P600, similar to pre-experimentally familiar figures and words, likely reflects improved recognition memory of meaningless pictorial and verbal items.

Induced Forgetting Is the Result of True Forgetting, Not Shifts in Decision-making Thresholds

Induced forgetting occurs when accessing an item in memory appears to harm memory representations of categorically related items. However, it is possible that the actual memory representations are unharmed. Instead, people may just change how they make decisions. Specifically, signal detection theory suggests this apparent forgetting may be due to participants shifting their decision criterion. Here, we used behavioral and electrophysiological measures to determine whether induced forgetting is truly due to changes in how items are represented or simply due to a shifting criterion. Participants' behavior and brain activity showed that induced forgetting was due to changes in the strength of the underlying representations, weighing against a criterion shift explanation of induced forgetting.

Recognition Receiver Operating Characteristic Curves: The Complex Influence of Input Statistics, Memory, and Decision-making

Receiver operating characteristic (ROC) analysis is the standard tool for studying recognition memory. In particular, the curvilinearity and the y-offset of recognition ROC curves have been interpreted as indicative of either memory strength (single-process models) or different memory processes (dual-process model). The distinction between familiarity and recollection has been widely studied in cognitive neuroscience in a variety of conditions, including lesions of different brain regions. We develop a computational model that explicitly shows how performance in recognition memory is affected by a complex and, as yet, underappreciated interplay of various factors, such as stimulus statistics, memory processing, and decision-making. We demonstrate that (1) the factors in the model affect recognition ROC curves in unexpected ways, (2) fitting R and F parameters according to the dual-process model is not particularly useful for understanding the underlying processes, and (3) the variability of recognition ROC curves and the controversies they have caused might be due to the uncontrolled variability in the contributing factors. Although our model is abstract, its functional components can be mapped onto brain regions, which are involved in corresponding functions. This enables us to reproduce and interpret in a coherent framework the diverse effects on recognition memory that have been reported in patients with frontal and hippocampal lesions. To conclude, our work highlights the importance of the rich interplay of a variety of factors in driving recognition memory performance, which has to be taken into account when interpreting recognition ROC curves.

Hazy memories in the courtroom: A review of alcohol and other drug effects on false memory and suggestibility

Alcohol and other psychoactive drugs are oftentimes implicated in legal cases. A pertinent question herein is whether such substances might adversely affect testimonies of victims, eyewitnesses, or suspects by propelling the formation of false memory and increasing susceptibility to suggestion. In the current review, we amassed all available evidence on the effects of intoxication on false memory formation and suggestibility, including the substances alcohol, benzodiazepines, cannabis, stimulants, hallucinogens, and antipsychotics. Our review indicated that alcohol and cannabis under certain conditions increased the susceptibility to false memories and/or suggestion with effect sizes ranging from medium to large. When intoxicated during an event, alcohol is most likely to increase this susceptibility at high intoxication levels or after a delay, whereas cannabis exerts detrimental effects during acute intoxication but not necessarily once sober. For other substances, ecologically valid research separating different memory phases is needed. Overall, differences between substances regarding false memory effects exist, suggesting that a nuanced approach is needed when dealing with intoxicated individuals in a legal context.

Why Are Trial-by-Trial, Strength-Based Criterion Shifts Hard to Observe? Is the Difficulty in the Mental Process Itself or in the Typical Cued Criterion Method?

In the cued criterion recognition paradigm (Stretch & Wixted, 1998b), trial-by-trial memory strength-based criterion shifts have been an elusive phenomenon. Often the criterion shifts do not occur. We suggest that the frequent failure in making criterion shifts in the literature is caused by participants’ failure to understand the rationale of the task as typically presented in an abstract format. In this study, participants studied words once or thrice and were asked at test to either classify the probes into “new,” “seen once,” or “seen 3 times” categories by pressing the corresponding keys or to make an old/new binary decision followed by an item presentation frequency, confidence, or a memory quality judgment. No memory strength cues were provided, and only one set of new items served as distractors for strong and weak targets. Robust trial-by-trial criterion shift was observed. We concluded that no cues distinguishing between strong and weak probes are necessary for obtaining this type of criterion shift when the tasks are designed to make good pragmatic sense for the participants. The reason why this type of criterion shift is typically hard to obtain in the cued criterion paradigm is not that the process itself is difficult but that the cued criterion method is hard for the participants to understand.

How does social competition affect true and false recognition?

Memory is highly susceptible to distortions, which can exert serious consequences in daily life. Despite this, we still know little about the role of factors that comprise social contexts in which memory processes occur. In the present study, we attempted to address this issue by examining how social competition influences true and false recognition. Participants performed a version of the Deese-Roediger-McDermott (DRM) paradigm designed to lure them into producing both true and false recognition either in competition against or independently of another person. We found that participants in the competition group showed lower levels of true and false recognition than those in the control group. Signal-detection analyses revealed that participants in both groups showed equivalent memory sensitivity for true recognition, while those in the competition group exhibited a decreased sensitivity for false recognition, which implies enhanced item-specific encoding during social competition. Moreover, participants in the competition group showed a more conservative response bias for both true and false recognition at retrieval than those in the control group, indicating a shift towards conservatism in decision strategy for both true and false recognition during social competition. The results provide compelling evidence for a decision-based reduction of true recognition and both encoding-based and decision-based reductions of false recognition under competitive contexts. Therefore, these novel findings may have implications both for understanding the powerful role of social competition on true and false memories and for understanding the potential role of social competition on other aspects of memory processes.

Assessing Theoretical Conclusions With Blinded Inference to Investigate a Potential Inference Crisis

Scientific advances across a range of disciplines hinge on the ability to make inferences about unobservable theoretical entities on the basis of empirical data patterns. Accurate inferences rely on both discovering valid, replicable data patterns and accurately interpreting those patterns in terms of their implications for theoretical constructs. The replication crisis in science has led to widespread efforts to improve the reliability of research findings, but comparatively little attention has been devoted to the validity of inferences based on those findings. Using an example from cognitive psychology, we demonstrate a blinded-inference paradigm for assessing the quality of theoretical inferences from data. Our results reveal substantial variability in experts’ judgments on the very same data, hinting at a possible inference crisis.

A strength-based mirror effect persists even when criterion shifts are unlikely

In single-item recognition, the strength-based mirror effect (SBME) is reliably obtained when encoding strength is manipulated between lists or participants. Debate surrounds the degree to which this effect is due to differentiation (e.g., Criss Journal of Memory and Language, 55, 461-478, 2006) or criterion shifts (e.g., Hicks & Starns Memory & Cognition, 42, 742-754, 2014). Problematically, differing underlying control processes may be equally capable of producing an SBME. The ability of criterion shifts to produce an SBME has been shown in prior work where differentiation was unlikely. The present work likewise produces an SBME under conditions where criterion shifts are unlikely. Specifically, we demonstrate that an SBME can be elicited without the typical number of trials needed to adjust one's decision criterion (Experiments 1, 2, and 5) and using encoding manipulations that do not explicitly alert participants that their memory quality has changed (Experiments 3 and 4). When taken in the context of the broader literature, these results demonstrate the need to prioritize memory models that can predict SBMEs via multiple underlying processes.

One mirror effect: The regularities of recognition memory

The mirror effect is a pattern of results generally found in two-condition recognition memory experiments that is consistent with normative signal detection theory as a model of recognition. However, the claim has been made that there is a distinct mirror effect, the "strength mirror effect," that differs from the normative one. This claim is based on experiments on recognition memory in which repetition or study time is varied to produce differences in accuracy, where typically the ordinary mirror effect pattern is absent. If this claim is correct, it has major implications for theories of recognition memory. Therefore, a full examination of the data that support the claim was called for. To do that, we replicated the basic demonstration of the no-mirror-effect data and analyzed it further in a series of experiments. The analysis showed the following: (1) Whether or not the mirror effect occurs is determined by whether the experimenter furnishes effective discriminanda that distinguish the weak and strong conditions for the participant. (2) Once Finding 1 is taken into account, no adjustments of or additions to the normative signal detection theory explanations are necessary. (3) There is only one mirror effect, and no separate "strength mirror effect."

Overcoming familiarity illusions in a single case with persistent déjà vu

While occasional déjà vu is benign in the general population, rare neuropsychological cases with persistent déjà vu have been described in the literature. We report the case of MN, a 25-year-old woman, who suffered a cerebral haemorrhage in the right thalamo-callosal region and experienced recurrent déjà vu episodes. Through clinical interviews and memory tasks related to déjà vu, we assumed that source memory errors and an inappropriate feeling of familiarity (measured by the number of false recognitions) were critically involved in MN's déjà vu. Based on this, we developed the first neuropsychological intervention dedicated to déjà vu. The rationale was to train MN to detect elements that could produce an inappropriate feeling of familiarity and to promote metacognitive awareness about déjà vu. This intervention was effective at reducing the frequency of déjà vu episodes in MN's daily life, as well as the number of false recognitions in memory tasks. In addition to its clinical contribution, this single-case study contributes to the limited literature on patients whose déjà vu is not related to epileptic abnormalities and medial temporal brain damage, and provide supportive evidence of the role of an erroneous feeling of familiarity and of metacognitive processes in déjà vu.

Cue quality and criterion setting in recognition memory

Previous studies on how people set and modify decision criteria in old-new recognition tasks (in which they have to decide whether or not a stimulus was seen in a study phase) have almost exclusively focused on properties of the study items, such as presentation frequency or study list length. In contrast, in the three studies reported here, we manipulated the quality of the test cues in a scene-recognition task, either by degrading through Gaussian blurring (Experiment 1) or by limiting presentation duration (Experiment 2 and 3). In Experiments 1 and 2, degradation of the test cue led to worse old-new discrimination. Most importantly, however, participants were more liberal in their responses to degraded cues (i.e., more likely to call the cue "old"), demonstrating strong within-list, item-by-item, criterion shifts. This liberal response bias toward degraded stimuli came at the cost of increasing the false alarm rate while maintaining a constant hit rate. Experiment 3 replicated Experiment 2 with additional stimulus types (words and faces) but did not provide accuracy feedback to participants. The criterion shifts in Experiment 3 were smaller in magnitude than Experiments 1 and 2 and varied in consistency across stimulus type, suggesting, in line with previous studies, that feedback is important for participants to shift their criteria.

Item-method directed forgetting: Effects at retrieval?

In an item-method directed forgetting paradigm, words are presented one at a time, each followed by an instruction to Remember or Forget; a directed forgetting effect is measured as better subsequent memory for Remember words than Forget words. The dominant view is that the directed forgetting effect arises during encoding due to selective rehearsal of Remember over Forget items. In three experiments we attempted to falsify a strong view that directed forgetting effects in recognition are due only to encoding mechanisms when an item method is used. Across 3 experiments we tested for retrieval-based processes by colour-coding the recognition test items. Black colour provided no information; green colour cued a potential Remember item; and, red colour cued a potential Forget item. Recognition cues were mixed within-blocks in Experiment 1 and between-blocks in Experiments 2 and 3; Experiment 3 added explicit feedback on the accuracy of the recognition decision. Although overall recognition improved with cuing when explicit test performance feedback was added in Experiment 3, in no case was the magnitude of the directed forgetting effect influenced by recognition cueing. Our results argue against a role for retrieval-based strategies that limit recognition of Forget items at test and posit a role for encoding intentions only.

Cross-task and cross-manipulation stability in shifting the decision criterion

In recognition memory experiments participants must discriminate between old and new items, a judgment influenced by response bias. Research has shown substantial individual differences in the extent to which people will strategically adjust their response bias to diagnostic cues such as the prior probability of an old item. Despite this significant between subject variability, shifts in bias have been found to be relatively predictive within individuals across memory tests. Experiment 1 sought to determine whether this predictability extends beyond memory. Results revealed that the amount a subject shifted response bias in a recognition memory task was significantly predictive of shifting in a visual perception task, suggesting that shifting can generalise outside of a specific testing domain. Experiment 2 sought to determine how predictive shifting would be across two manipulations well known to induce shifts in bias: a probability manipulation and a response payoff manipulation. A modest positive relationship between these two methods was observed, suggesting that shifting behaviour is relatively predictive across different manipulations of shifting. Overall, results from both experiments suggest that response bias shifting, like response bias setting, is a relatively stable behaviour within individuals despite changes in test domain and test manipulation.

Ignoring memory hints: The stubborn influence of environmental cues on recognition memory

Recognition judgments can benefit from the use of environmental cues that signal the general likelihood of encountering familiar versus unfamiliar stimuli. While incorporating such cues is often adaptive, there are circumstances (e.g., eyewitness testimony) in which observers should fully ignore environmental cues in order to preserve memory report fidelity. The current studies used the explicit memory cueing paradigm to examine whether participants could intentionally ignore reliable environmental cues when instructed. Three experiments demonstrated that participants could volitionally dampen the directional influence of environmental cues on their recognition judgments (i.e., whether influenced to respond "old" or "new") but did not fully eliminate their influence. Although monetary incentives diminished the mean influence of cues on responses rates, finer grained individual differences analysis, as well as confidence and RTs analyses, demonstrated that participants were still systematically influenced. These results demonstrate that environmental cues presented at test remain a potent influence on recognition decisions and subjective confidence even when ostensibly ignored. (PsycINFO Database Record

Memória de Reconhecimento: Modelos de Processamento Simples versus Duplo

Resumo O processo de reconhecimento de memórias consiste em discriminar informações previamente encontradas de informações novas. Duas abordagens teóricas divergentes buscam explicar esse fenômeno. A primeira propõe que o reconhecimento se baseia essencialmente na sensação de familiaridade gerada por cada estímulo. A segunda propõe que além da intensidade da familiaridade, a evocação de aspectos qualitativos e contextuais dos eventos memorizados possui um papel fundamental no processo de reconhecimento. Aspectos teóricos e metodológicos inerentes às duas linhas teóricas são criticamente discutidos no presente artigo, sendo que o resultado dessa discussão se apresenta favorável à segunda perspectiva teórica.

The effects of weak versus strong relational judgments on response bias in Two-Alternative-Forced-Choice recognition: Is the test criterion-free?

It is widely believed that a Two-Alternative-Forced-Choice (2AFC) in an old/new recognition memory test is made by comparing the two items and choosing the item with the higher strength. For this reason, it is considered to be criterion-free by some researchers. We found evidence that subjects probabilistically compromised the comparison by choosing the left item when they recognized it as old. Using both normal test pairs (comprised of one new and one old item) and two types of null pairs (comprised of both-new or both-old items), we found that a left-biased choice was coupled with higher hit and false alarm rates and a shorter left than right-choice RT for the normal pairs, consistent with the hypothesis of a bias for making a choice on the basis of a left individual-item recognition. For the null pairs, RT was much longer for the both-new than for the both-old pairs, providing additional evidence for basing decision on an individual-item's absolute, rather than a relative, familiarity. Additionally, subjects gave higher confidence ratings to choices for the both-old than the normal and both-new pairs, again suggesting that their decision was based on absolute familiarity of the items. The results were found to be not due to a fast-response instruction. A comparative judgment experiment in which subjects chose the item higher or lower in an attribute magnitude did not show the response side bias and RT asymmetry. The presence of bias in the former, and the absence of it in the latter can be explained by a weak versus strong relational judgment in the former and the latter type of 2AFC, respectively. We discuss the implications these findings have for the use of the 2AFC as a method for testing recognition memory.

They can take a hint: Older adults effectively integrate memory cues during recognition

Adaptively biasing recognition judgments in light of environmental cues improves net accuracy. Based on previous work suggesting that strategically shifting biases on a trial-wise basis should be cognitively demanding, the authors predicted that older adults would not achieve the same accuracy benefits from environmental cues as the young. However, despite showing clear declines in cognitive control as indexed by complex span, older adults demonstrated similar accuracy gains and similar alterations of response probabilities with cues of 75% reliability (Experiment 1) and more complex cues spanning 3 levels of reliability (Experiment 2). Despite preserved gains in accuracy, older adults clearly demonstrated disproportionate slowing that was specific to trials in which cues were invalid. This slowing may reflect impairments in behavioral inhibition that could impinge upon accuracy were responding increasingly sped and future work manipulating response speed and measures of inhibition may yield further insights.

Dubious decision evidence and criterion flexibility in recognition memory

When old–new recognition judgments must be based on ambiguous memory evidence, a proper criterion for responding “old” can substantially improve accuracy, but participants are typically suboptimal in their placement of decision criteria. Various accounts of suboptimal criterion placement have been proposed. The most parsimonious, however, is that subjects simply over-rely on memory evidence – however faulty – as a basis for decisions. We tested this account with a novel recognition paradigm in which old–new discrimination was minimal and critical errors were avoided by adopting highly liberal or conservative biases. In Experiment 1, criterion shifts were necessary to adapt to changing target probabilities or, in a “security patrol” scenario, to avoid either letting dangerous people go free (misses) or harming innocent people (false alarms). Experiment 2 added a condition in which financial incentives drove criterion shifts. Critical errors were frequent, similar across sources of motivation, and only moderately reduced by feedback. In Experiment 3, critical errors were only modestly reduced in a version of the security patrol with no study phase. These findings indicate that participants use even transparently non-probative information as an alternative to heavy reliance on a decision rule, a strategy that precludes optimal criterion placement.

Differential effects of emotional cues on components of prospective memory: an ERP study

So far, little is known about the neurocognitive mechanisms associated with emotion effects on prospective memory (PM) performance. Thus, this study aimed at disentangling possible mechanisms for the effects of emotional valence of PM cues on the distinct phases composing PM by investigating event-related potentials (ERPs). Participants were engaged in an ongoing N-back task while being required to perform a PM task. The emotional valence of both the ongoing pictures and the PM cues was manipulated (pleasant, neutral, unpleasant). ERPs were recorded during the PM phases, such as encoding, maintenance, and retrieval of the intention. A recognition task including PM cues and ongoing stimuli was also performed at the end of the sessions. ERP results suggest that emotional PM cues not only trigger an automatic, bottom-up, capture of attention, but also boost a greater allocation of top-down processes. These processes seem to be recruited to hold attention toward the emotional stimuli and to retrieve the intention from memory, likely because of the motivational significance of the emotional stimuli. Moreover, pleasant PM cues seemed to modulate especially the prospective component, as revealed by changes in the amplitude of the ERP correlates of strategic monitoring as a function of the relevance of the valence for the PM task. Unpleasant pictures seemed to modulate especially the retrospective component, as revealed by the largest old/new effect being elicited by unpleasant PM pictures in the recognition task.

Social influences on adaptive criterion learning

People adaptively shift decision criteria when given biased feedback encouraging specific types of errors. Given that work on this topic has been conducted in nonsocial contexts, we extended the literature by examining adaptive criterion learning in both social and nonsocial contexts. Specifically, we compared potential differences in criterion shifting given performance feedback from social sources varying in reliability and from a nonsocial source. Participants became lax when given false positive feedback for false alarms, and became conservative when given false positive feedback for misses, replicating prior work. In terms of a social influence on adaptive criterion learning, people became more lax in response style over time if feedback was provided by a nonsocial source or by a social source meant to be perceived as unreliable and low-achieving. In contrast, people adopted a more conservative response style over time if performance feedback came from a high-achieving and reliable source. Awareness that a reliable and high-achieving person had not provided their feedback reduced the tendency to become more conservative, relative to those unaware of the source manipulation. Because teaching and learning often occur in a social context, these findings may have important implications for many scenarios in which people fine-tune their behaviors, given cues from others.

Hypergraph-based recognition memory model for lifelong experience

Cognitive agents are expected to interact with and adapt to a nonstationary dynamic environment. As an initial process of decision making in a real-world agent interaction, familiarity judgment leads the following processes for intelligence. Familiarity judgment includes knowing previously encoded data as well as completing original patterns from partial information, which are fundamental functions of recognition memory. Although previous computational memory models have attempted to reflect human behavioral properties on the recognition memory, they have been focused on static conditions without considering temporal changes in terms of lifelong learning. To provide temporal adaptability to an agent, in this paper, we suggest a computational model for recognition memory that enables lifelong learning. The proposed model is based on a hypergraph structure, and thus it allows a high-order relationship between contextual nodes and enables incremental learning. Through a simulated experiment, we investigate the optimal conditions of the memory model and validate the consistency of memory performance for lifelong learning.

Examining Event-Related Potential (ERP) correlates of decision bias in recognition memory judgments

Memory judgments can be based on accurate memory information or on decision bias (the tendency to report that an event is part of episodic memory when one is in fact unsure). Event related potentials (ERP) correlates are important research tools for elucidating the dynamics underlying memory judgments but so far have been established only for investigations of accurate old/new discrimination. To identify the ERP correlates of bias, and observe how these interact with ERP correlates of memory, we conducted three experiments that manipulated decision bias within participants via instructions during recognition memory tests while their ERPs were recorded. In Experiment 1, the bias manipulation was performed between blocks of trials (automatized bias) and compared to trial-by-trial shifts of bias in accord with an external cue (flexibly controlled bias). In Experiment 2, the bias manipulation was performed at two different levels of accurate old/new discrimination as the memory strength of old (studied) items was varied. In Experiment 3, the bias manipulation was added to another, bottom-up driven manipulation of bias induced via familiarity. In the first two Experiments, and in the low familiarity condition of Experiment 3, we found evidence of an early frontocentral ERP component at 320 ms poststimulus (the FN320) that was sensitive to the manipulation of bias via instruction, with more negative amplitudes indexing more liberal bias. By contrast, later during the trial (500–700 ms poststimulus), bias effects interacted with old/new effects across all three experiments. Results suggest that the decision criterion is typically activated early during recognition memory trials, and is integrated with retrieved memory signals and task-specific processing demands later during the trial. More generally, the findings demonstrate how ERPs can help to specify the dynamics of recognition memory processes under top-down and bottom-up controlled retrieval conditions.

Response bias in recognition memory as a cognitive trait

According to signal detection theory, old-new recognition decisions can be affected by response bias, a general proclivity to respond either "old" or "new." In recognition experiments, response bias is usually analyzed at a group level, but substantial individual differences in bias can underlie group means. These differences suggest that, independent of any experimental manipulation, some people require more memory evidence than do others before they are willing to call an item "old." In four experiments, we investigated the possibility that recognition response bias is a partial function of a trait-like predisposition. Bias was highly correlated across two recognition study-test cycles separated by 10 min (Experiment 1). A nearly identical correlation was observed when the tasks were separated by one week (Experiment 2). Bias correlations remained significant even when the stimuli differed sharply between the first and second study-test cycles (Experiment 3). No relationship was detected between bias and response strategies in two general knowledge tests (Experiments 2 and 4), but bias did weakly predict frequency of false recall in the Deese/Roediger-McDermott (DRM) paradigm (Experiment 4). This evidence of trait-like stability suggests an entirely different aspect of response bias than that studied by examining its modulation by task variables, one for which complete theories of recognition memory may need to account.

Strength cues and blocking at test promote reliable within-list criterion shifts in recognition memory

In seven experiments, we explored the potential for strength-based, within-list criterion shifts in recognition memory. People studied a mix of target words, some presented four times (strong) and others studied once (weak). In Experiments 1, 2, 4A, and 4B, the test was organized into alternating blocks of 10, 20, or 40 trials. Each block contained lures intermixed with strong targets only or weak targets only. In strength-cued conditions, test probes appeared in a unique font color for strong and weak blocks. In the uncued conditions of Experiments 1 and 2, similar strength blocks were tested, but strength was not cued with font color. False alarms to lures were lower in blocks containing strong target words, as compared with lures in blocks containing weak targets, but only when strength was cued with font color. Providing test feedback in Experiment 2 did not alter these results. In Experiments 3A-3C, test items were presented in a random order (i.e., not blocked by strength). Of these three experiments, only one demonstrated a significant shift even though strength cues were provided. Overall, the criterion shift was larger and more reliable as block size increased, and the shift occurred only when strength was cued with font color. These results clarify the factors that affect participants' willingness to change their response criterion within a test list.

Ventral fronto-temporal pathway supporting cognitive control of episodic memory retrieval

Achieving our goals often requires guiding access to relevant information from memory. Such goal-directed retrieval requires interactions between systems supporting cognitive control, including ventrolateral prefrontal cortex (VLPFC), and those supporting declarative memory, such as the medial temporal lobes (MTL). However, the pathways by which VLPFC interacts with MTL during retrieval are underspecified. Prior neuroanatomical evidence suggests that a polysynaptic ventral fronto-temporal pathway may support VLPFC-MTL interactions. To test this hypothesis, human participants were scanned using fMRI during performance of a source-monitoring task. The strength of source information was varied via repetition during encoding. Single encoding events should produce a weaker memory trace, thus recovering source information about these items should demand greater cognitive control. Results demonstrated that cortical targets along the ventral path--anterior VLPFC, temporal pole, anterior parahippocampus, and hippocampus--exhibited increases in univariate BOLD response correlated with increases in controlled retrieval demand, independent of factors related to response selection. Further, a functional connectivity analysis indicated that these regions functionally couple and are distinguishable from a dorsal pathway related to response selection demands. These data support a ventral retrieval pathway linking PFC and MTL.

Where is the criterion noise in recognition? (Almost) everyplace you look: comment on Kellen, Klauer, and Singmann (2012)

Recent articles, including Benjamin, Diaz, and Wee (2009), have argued that recognition memory may be better understood if consideration is given to sources of noise in the decisions, as well as to those in the representations, underlying recognition judgments. They based that conclusion on a wide consideration of persisting mysteries in recognition research as well as a new experimental paradigm involving ensemble recognition. Kellen, Klauer, and Singmann (2012) reanalyzed Benjamin et al.'s data and introduced their own new experimental paradigm to this debate. They concluded that criteria do not vary much from trial to trial in recognition testing and, thus, that decision noise in recognition is small or nonexistent. However, their alternative interpretation of Benjamin et al.'s data relies on a questionable conclusion to reject all models in which the locations of criteria are restricted to be the same across ensembles and a meta-assumption that a model should be rejected as false if it yields unconventional parameters. In addition, their experimental logic relies on the assumption that ranking tasks are always bias-free. Here, I question these assumptions and suggest avenues for reconciliation between these contrasting claims.

Individual differences in shifting decision criterion: a recognition memory study

An ability to flexibly shift a decision criterion can be advantageous. For example, a known change in the base rate of targets and distractors on a recognition memory test will lead optimal decision makers to shift their criterion accordingly. In the present study, 95 individuals participated in two recognition memory tests that included periodic changes in the base rate probability that the test stimulus had been presented during the study session. The results reveal a wide variability in the tendency to shift decision criterion in response to this probability information, with some appropriately shifting and others not shifting at all. However, participants were highly reliable in their tendency to shift criterion across tests. The goal of the present study was to explain what factors account for these individual differences. To accomplish this, over 50 variables were assessed for each individual (e.g., personality, cognitive style, state of mind). Using a regression model that incorporated different sets of factors, over 50% of the variance was accounted for. The results of the analysis describe the total, direct, and mediating effects on criterion shifting from factors that include memory strength, strategy, and inherent characteristics such as a fun-seeking personality, a negative affect, and military rank. The results are discussed with respect to understanding why participants rarely chose an optimal decision-making strategy and provide greater insight into the underlying mechanisms of recognition memory.

Recognition of categorised words: repetition effects in rote study

In the recognition-memory mirror effect one stimulus class exhibits both more hits and fewer false alarms than a contrasting class. This outcome is frequently detected when strong (e.g., repeated, long-duration study) and weak items have appeared in different lists but less so within lists. The mirror effect may reflect people's assignment of a more lenient recognition criterion to the weak than the strong class. The present study asked whether a paradigm that has yielded within-list mirror effects when participants make gist ratings during study (Singer, 2009, 2011) likewise obtains in rote study. In Experiments 1 and 2 people studied words from category pairs such that the stimuli from one category only were repeated three times. Both hits and false alarms were consistently higher for the repeated than the unrepeated condition, a pattern labelled "concordant" (rather than mirror). This might reflect the either a positive "distribution shift" of the repeated-category lures or a metacognitive strategy. Experiment 3 coupled the same study procedure with two-alternative forced-choice testing (2AFC) to deny the distribution shift explanation. The sorts of strategy that might favour repeated over unrepeated lures are considered.

Metacognitive awareness and adaptive recognition biases

Prior literature has primarily focused on the negative influences of misleading external sources on memory judgments. This study investigated whether participants can capitalize on generally reliable recommendations in order to improve their net performance; the focus was on potential roles for metacognitive monitoring (i.e., knowledge about one's own memory reliability) and performance feedback. In Experiment 1, participants received explicit external recommendations (Likely Old or Likely New) that were 75% valid during recognition tests containing deeply and shallowly encoded materials. In Experiment 2, participants received recommendations of differing validity (65% and 85%). Discrimination improved across both experiments when external recommendations were present versus absent. This improvement was influenced by metacognitive monitoring ability measured in the absence of recommendations. Thus, effective incorporation of external recommendations depended in part on how sensitive observers were to gradations of their internal evidence when recommendations were absent. Finally, corrective feedback did not improve participants' ability to use external recommendations, suggesting that metacognitive monitoring ability during recognition is not easily improved via feedback.

Effects of Exposure on Discrimination of Similar Stimuli and on Memory for Their Unique and Common Features

Human participants received exposure to similar visual stimuli (AW and BW) that shared a common feature (W). Experiment 1 demonstrated that subsequent discrimination between AW and BW was more accurate when the two stimuli were preexposed on an intermixed schedule (AW, BW, AW, BW…) than when they were preexposed on a blocked schedule (AW, AW…BW, BW…): the intermixed–blocked effect. Furthermore, memory for the unique features of the stimuli (A and B) was better when the stimuli were preexposed on an intermixed schedule than when they were preexposed on a blocked schedule. Conversely, memory for the common features of the stimuli (W) was better when the stimuli were preexposed on a blocked schedule than when they were preexposed on an intermixed schedule. Experiment 2 again demonstrated the intermixed–blocked effect, but participants were preexposed to the stimuli in such a way that the temporal spacing between exposures to the unique features was equated between schedules. Memory for the unique and common features was similar to that found in Experiment 1. These findings support the proposal that perceptual learning depends on a mechanism that enhances memory for the unique features and reduces memory for common features.

Diffusion model drift rates can be influenced by decision processes: an analysis of the strength-based mirror effect

Improving memory for studied items (targets) often helps participants reject nonstudied items (lures), a pattern referred to as the strength-based mirror effect (SBME). Criss (2010) demonstrated the SBME in diffusion model drift rates; that is, the target drift rate was higher and the lure drift rate was lower for lists of words studied 5 times versus lists of words studied once. She interpreted the drift rate effect for lures as evidence for the differentiation process, whereby strong memory traces produce a poorer match to lure items than do weak memory traces. However, she noted that strength may have also affected a model parameter called the drift criterion-a participant-controlled decision parameter that defines the zero point in drift rate. We directly contrasted the differentiation and drift-criterion accounts by manipulating list strength either at both encoding and retrieval (which produces a differentiation difference in the studied traces) or at retrieval only (which equates differentiation from the study list but provides the opportunity to change decision processes based on strength). Across 3 experiments, results showed that drift rates for lures were lower on strong tests than on weak tests, and this effect was observed even when strength was varied at retrieval alone. Therefore, results provided evidence that the SBME is produced by changes in decision processes, not by differentiation of memory traces.

Unmasking a shady mirror effect: Recognition of normal versus obscured faces

Hockley, Hemsworth, and Consoli (1999) found that following the study of normal faces, a recognition test of normal faces versus faces wearing sunglasses produced a mirror effect: The sunglasses manipulation decreased hit rates and increased false-alarm rates. The stimuli used by Hockley et al. (1999) consisted of separate poses of models wearing or not wearing sunglasses. In the current experiments, we separately manipulated same versus different depictions of individual faces and whether or not the faces were partially obscured. The results of a simulation and four experiments suggest that the test-based, mirror effect observed by Hockley et al. (1999) is actually two separable effects.