Signal-detection, threshold, and dual-process models of recognition memory: ROCs and conscious recollection

The influence of emotion on temporal context models

Temporal context models (TCMs) have been influential in understanding episodic memory and its neural underpinnings. Recently, TCMs have been extended to explain emotional memory effects, one of the most clinically important findings in the field of memory research. This review covers recent advances in hypotheses for the neural representation of spatiotemporal context through the lens of TCMs, including their ability to explain the influence of emotion on episodic and temporal memory. In recent years, simplifying assumptions of "classical" TCMs - with exponential trace decay and the mechanism by which temporal context is recovered - have become increasingly clear. The review also outlines how recent advances could be incorporated into a future TCM, beyond classical assumptions, to integrate emotional modulation.

Comparing two unitisation manipulations: effects on familiarity, recollection-based recognition, and semantic interference

The recognition of associative memory can be significantly influenced by the use of an encoding strategy known as unitisation, which has been implemented through various manipulations. However, [Shao, H., Opitz, B., Yang, J., & Weng, X. (2016). Recollection reduces unitised familiarity effect. Memory (Hove, England), 24(4), 535-547. https://doi.org/10.1080/09658211.2015.1021258] found intriguing distinctions between two common manipulations, the compound task and the imagery task, leading to a dispute. We propose that differences in levels of processing in the imagery task may account for these discrepancies. This study tested our hypothesis using two approaches. The first two experiments utilised the R/K paradigm to investigate the effects of these methods on familiarity-based and recollection-based recognition. The results demonstrated that familiarity was increased in the compound task, while recollection was increased in the imagery task. In the subsequent two experiments, an interference paradigm was employed to examine differences in semantic processing within the two tasks. The results showed that the compound task did not impact participants' inclination towards lures, while the imagery task led to a bias towards semantic lures over episodic lures, suggesting that the two encodings in the imagery task involve different levels of semantic processing. These results support our hypothesis and underscore the importance of carefully choosing comparisons that account for other variables in the study of unitisation.

Menopause Status and Within-Group Differences in Chronological Age Affect the Functional Neural Correlates of Spatial Context Memory in Middle-Aged Females

Reductions in the ability to encode and retrieve past experiences in rich spatial contextual detail (episodic memory) are apparent by midlife-a time when most females experience spontaneous menopause. Yet, little is known about how menopause status affects episodic memory-related brain activity at encoding and retrieval in middle-aged premenopausal and postmenopausal females, and whether any observed group differences in brain activity and memory performance correlate with chronological age within group. We conducted an event-related task fMRI study of episodic memory for spatial context to address this knowledge gap. Multivariate behavioral partial least squares was used to investigate how chronological age and retrieval accuracy correlated with brain activity in 31 premenopausal females (age range, 39.55-53.30 years; mean age, 44.28 years; SD age, 3.12 years) and 41 postmenopausal females (age range, 46.70-65.14 years; mean age, 57.56 years; SD age, 3.93 years). We found that postmenopausal status, and advanced age within postmenopause, was associated with lower spatial context memory. The fMRI analysis showed that only in postmenopausal females, advanced age was correlated with decreased activity in occipitotemporal, parahippocampal, and inferior parietal cortices during encoding and retrieval, and poorer spatial context memory performance. In contrast, only premenopausal females exhibited an overlap in encoding and retrieval activity in angular gyrus, midline cortical regions, and prefrontal cortex, which correlated with better spatial context retrieval accuracy. These results highlight how menopause status and chronological age, nested within menopause group, affect episodic memory and its neural correlates at midlife.SIGNIFICANCE STATEMENT This is the first fMRI study to examine how premenopause and postmenopause status affect the neural correlates of episodic memory encoding and retrieval, and how chronological age contributes to any observed group similarities and differences. We found that both menopause status (endocrine age) and chronological age affect spatial context memory and its neural correlates. Menopause status directly affected the direction of age-related and performance-related correlations with brain activity in inferior parietal, parahippocampal, and occipitotemporal cortices across encoding and retrieval. Moreover, we found that only premenopausal females exhibited cortical reinstatement of encoding-related activity in midline cortical, prefrontal, and angular gyrus, at retrieval. This suggests that spatial context memory abilities may rely on distinct brain systems at premenopause compared with postmenopause.

Hoarding titmice predominantly use Familiarity, and not Recollection, when remembering cache locations

Scatter-hoarding birds find their caches using spatial memory and have an enlarged hippocampus. Finding a cache site could be achieved using either Recollection (a discrete recalling of previously experienced information) or Familiarity (a feeling of "having encountered something before"). In humans, these two processes can be distinguished using receiver operating characteristic (ROC) curves. ROC curves for olfactory memory in rats have shown the hippocampus is involved in Recollection, but not Familiarity. We test the hypothesis that food-hoarding birds, having a larger hippocampus, primarily use Recollection to find their caches. We validate a novel method of constructing ROC curves in humans and apply this method to cache retrieval by coal tits (Periparus ater). Both humans and birds mainly use Familiarity in finding their caches, with lower contribution of Recollection. This contribution is not significantly different from chance in birds, but a small contribution cannot be ruled out. Memory performance decreases with increasing retention interval in birds. The ecology of food-hoarding Parids makes it plausible that they mainly use Familiarity in the memory for caches. The larger hippocampus could be related to associating cache contents and temporal context with cache locations, rather than Recollection of the spatial information itself.

To be or not to be relevant: Comparing short- and long-term consequences across working memory prioritization procedures

Priority-based allocation of attentional resources has shown robust effects in working memory (WM) with both cue-based and reward-based prioritization. However, direct comparisons between these effects in WM are needed. Additionally, the consequences of WM prioritization for remembering in the long term remain unclear for both prioritization procedures. Here, we tested and compared the immediate and long-term memory (LTM) effects of cue-based versus reward-based retrospective prioritization of WM content. Participants encoded four memory items and were then indicated to prioritize one of the items through the presentation of either a retro-cue or a reward pattern. We then tested their immediate and delayed memory. The results of the first experiment showed better memory for prioritized than for unprioritized information in WM and LTM, but the WM effect was driven solely by the retro-cue, making it difficult to interpret any reward-based effects in LTM. In the second experiment, using a more explicit and meaningful reward-based manipulation, the results showed a prioritization benefit in WM for both prioritization procedures. In LTM, however, the prioritization effect was predominantly driven by the retro-cue manipulation. Taken together, we found that (1) the way in which attention is directed in WM impacts the size of the prioritization benefit in WM, (2) WM prioritization generally results in a prioritization effect in LTM, and (3) that the effect in LTM is more robust for cue-based prioritization. Exploratory analyses indicated that the LTM effect of cue-based prioritization reflected a cost in performance for noncued items rather than a benefit for cued items.

Learning facilitates dual-process face recognition regardless of holistic processing

Much evidence suggests that faces are recognized based on their global familiarity in a signal-detection manner. However, experiments drawing this conclusion typically present study lists of faces only once or twice, and the nature of face recognition at higher levels of learning remains unclear. Here, three experiments are reported in which participants studied some faces eight times and others twice and then took a recognition test containing previously viewed faces, entirely new faces, and faces which recombined the parts of previously viewed faces. Three measures converged to suggest that study list repetition increased the likelihood of participants rejecting recombined faces as new by recollecting that their parts were studied but in a different combination, and that manipulating holistic or Gestalt-like processing-a hallmark of face perception-qualitatively preserved its effect on how memory judgments are made. This suggests that face learning causes a shift from the use of a signal-detection strategy to the use of a dual-process strategy of face recognition regardless of holistic processing.

Does ROC asymmetry reverse when detecting new stimuli? Reinvestigating whether the retrievability of mnemonic information is task-dependent

Recently, it has been suggested that the mnemonic information that underlies recognition decisions changes when participants are asked to indicate whether a test stimulus is new rather than old (Brainerd et al., 2021, Journal of Experimental Psychology: Learning Memory, and Cognition, advance online publication). However, some observations that have been interpreted as evidence for this assertion need not be due to mnemonic changes, but may instead be the result of conservative response strategies if the possibility of asymmetric receiver operating characteristics (ROCs) is taken into account. Conversely, recent findings in support of asymmetric ROCs rely on the assumption that the mnemonic information accessed by the decision-maker does not depend on whether an old or a new item is considered to be the target Kellen et al. (2021, Psychological Review 128[6], 1022-1050). Here, we aim to clarify whether there is such a difference in accessibility of mnemonic information by applying signal detection theory. To this end, we used two versions of a simultaneous detection and identification task in which we presented participants with two test stimuli at a time. In one version, the old item was the target; in the other, the new item was the target. This allowed us to assess differences in mnemonic information retrieved in the two tasks while taking possible ROC asymmetry into account. Results clearly indicate that there is indeed a difference in the accessibility of mnemonic information as postulated by (Brainerd et al., 2021, Journal of Experimental Psychology: Learning Memory, and Cognition, advance online publication).

Expectation of irrelevant novel stimuli has no consistent effect on recognition memory

Novelty is defined as the part of an experience that is not yet represented by memory systems. Novelty has been claimed to exert various memory-enhancing effects. A pioneering study by Wittmann et al. (2007) has shown that memory formation may even benefit from the expectation of novelty. We aimed to replicate this assumed memory effect in four behavioral studies. However, our results do not support the idea that anticipated novel stimuli are more memorable than unexpected novelty. In our experiments, we systematically manipulated the novelty predicting cues to ensure that the expectations were correctly formed by the participants, however, the results showed that there was no memory enhancement for expected novel pictures in any of the examined indices, thus we could not replicate the main behavioral finding of Wittmann et al. (2007). These results call into question the original effect, and we argue that this fits more into current thinking on memory formation and brain function in general. Our results are more consistent with the view that unexpected stimuli are more likely to be retained by memory systems. Predictive coding theory suggests that unexpected stimuli are prioritized by the nervous system and this may also benefit memory processes. Novel stimuli may be unexpected and thus recognized better in some experimental setups, yet novelty and unexpectedness do not always coincide. We hope that our work can bring more consistency in the literature on novelty, as educational methods in general could also benefit from this clarification.

OUP accepted manuscript

Retrieval practice improves retention of information in long-term memory more than restudy, but the underlying neural mechanisms of this “retrieval practice effect” (RPE) remain poorly understood. Therefore, we investigated the behavioral and neural differences between previously retrieved versus restudied items at final retrieval. Thirty younger (20–30 years old) and twenty-five older (50+ years old) adults learned familiar and new picture stimuli either through retrieval or restudy. At final recognition, hemodynamic activity was measured using functional magnetic resonance imaging (fMRI). Behaviorally, younger and older adults showed similar benefits of retrieval practice, with higher recollection, but unchanged familiarity rates. In a univariate analysis of the fMRI data, activation in medial prefrontal cortex and left temporal regions correlated with an individual’s amount of behavioral benefit from retrieval practice, irrespective of age. Compatible with this observation, in a multivariate representational similarity analysis (RSA), retrieval practice led to an increase in pattern similarity for retested items in a priori defined regions of interest, including the medial temporal lobe, as well as prefrontal and parietal cortex. Our findings demonstrate that retrieval practice leads to enhanced long-term memories in younger and older adults alike, and this effect may be driven by fast consolidation processes.

Familiarity in Mild Cognitive Impairment as a Function of Patients' Clinical Outcome 4 Years Later

OBJECTIVES

The current study addresses the nature of memory difficulties in amnestic mild cognitive impairment (aMCI). Whereas recollection is consistently found to be impaired in aMCI, the results on familiarity are divergent. One potential factor that could explain this divergence in findings relates to the heterogeneity of aMCI patients, so that only those aMCI patients who develop Alzheimer disease (AD) may present with impaired familiarity. The present study aimed at testing this hypothesis.

METHODS

A group of 45 aMCI patients and a group of 26 healthy older adults performed a verbal recognition memory test with the Remember/Know paradigm to assess recollection and familiarity processes. All participants were followed for 4 years with clinical and neuropsychological testing. At the end of follow-up, 22 aMCI patients progressed to AD and 23 aMCI patients remained stable. Initial memory performance was compared between the 3 groups.

RESULTS

Whereas recollection was severely diminished in all aMCI patients, familiarity accuracy (and consequently global recognition accuracy) was found to be impaired only in aMCI patients who subsequently developed AD.

CONCLUSION

These findings suggest that the enrichment of the aMCI population with predementia stage patients may modulate the likelihood to observe familiarity deficits, and impaired global recognition accuracy may accompany incipient AD.

Functional Specialization of the Medial Temporal Lobes in Human Recognition Memory: Dissociating Effects of Hippocampal versus Parahippocampal Damage

A central debate in the systems neuroscience of memory concerns whether different medial temporal lobe (MTL) structures support different processes in recognition memory. Using two recognition memory paradigms, we tested a rare patient (MH) with a perirhinal lesion that appeared to spare the hippocampus. Consistent with a similar previous case, MH showed impaired familiarity and preserved recollection. When compared with patients with hippocampal lesions appearing to spare perirhinal cortex, MH showed greater impairment on familiarity and less on recollection. Nevertheless, the hippocampal patients also showed impaired familiarity compared with healthy controls. However, when replacing this traditional categorization of patients with analyses relating memory performance to continuous measures of damage across patients, hippocampal volume uniquely predicted recollection, whereas parahippocampal, rather than perirhinal, volume uniquely predicted familiarity. We consider whether the familiarity impairment in MH and our patients with hippocampal lesions arises from "subthreshold" damage to parahippocampal cortex (PHC). Our data provide the most compelling neuropsychological support yet for dual-process models of recognition memory, whereby recollection and familiarity depend on different MTL structures, and may support a role for PHC in familiarity. Our study highlights the value of supplementing single-case studies with examinations of continuous brain-behavior relationships across larger patient groups.

Probing emotional recognition memory: how different response formats affect response behaviour

Receiver-operating characteristic curves from confidence ratings and remember/know (R/K) judgments are often used to estimate the contribution of familiarity and recollection to recognition memory. Both coming with specific advantages and disadvantages, which could be reduced by their combination. Little is known how the combination of both methods impacts response behaviour. This could be particularly important for emotional memory research, which is susceptible to variation in meta-mnemonic processes. We obtained reference performance indices from the two methods, instructing individuals to give confidence ratings or R/K judgments in one step. Against these, we contrasted R/K judgments in a two-step format and two combined formats, confidence ratings followed by R/K judgments and vice versa. Regarding reference formats, confidence ratings resulted in more liberal response criteria and false alarm rates than R/K judgments. Two-step R/K judgments and confidence ratings followed by R/K judgments resulted in patterns similar to one-step R/K judgments. Reversing the order resulted in more liberal response biases, higher hit and false alarms rates. Recollection and familiarity were unaffected by response formats. Valence effects did not vary with response formats. The present results suggest that confidence ratings followed by R/K judgments provide the advantages of both without biasing response behaviour.

Spontaneous recognition: Investigating the role of working memory

In almost every aspect of life, focusing on a target and ignoring distractors effectively is very important. Alternative to the common view, distraction may aid recognition via triggering automatic responses. Spontaneous recognition (SR) can be defined as the unintentional recognition of target stimuli and is measured by the effect of familiarity to distractors on a recognition task. Research has indicated that previously seen or not seen (old/new) distractors affect the recognition of targets. This research aimed to investigate the influence of working memory load on SR. A dual-task was designed to ensure engagement in two tasks-namely, the memory Stroop task (recognition task) and the n-back task (working memory task) at the same time. This design enabled an investigation of the influence of working memory load and allowed for further exploration of the influence of episodic memory load and the characteristics of n-back task. The results are in line with previous research; participants were more accurate when target and distractor were congruent versus when they were incongruent, but only when WM load was high. This interaction was modulated by episodic memory load and n-back task trials (match/mismatch). It was concluded that many factors may contribute to the SR effect. This research demonstrated that the SR effect is determined by WM availability and recognition processes engaged in another task.

Reward anticipation selectively boosts encoding of gist for visual objects

Reward anticipation at encoding enhances later recognition, but it is unknown to what extent different levels of processing at encoding (gist vs. detail) can benefit from reward-related memory enhancement. In the current study, participants (N = 50) performed an incidental encoding task in which they made gist-related or detail-related judgments about pairs of visual objects while in anticipation of high or low reward. Results of a subsequent old/new recognition test revealed a reward-related memory benefit that was specific to objects from pairs encoded in the attention-to-gist condition. These findings are consistent with the theory of long-axis specialization along the human hippocampus, which localizes gist-based memory processes to the anterior hippocampus, a region highly interconnected with the dopaminergic reward network.

Dopamine Related Genes Differentially Affect Declarative Long-Term Memory in Healthy Humans

In humans, monetary reward can promote behavioral performance including response times, accuracy, and subsequent recognition memory. Recent studies have shown that the dopaminergic system plays an essential role here, but the link to interindividual differences remains unclear. To further investigate this issue, we focused on previously described polymorphisms of genes affecting dopaminergic neurotransmission: DAT1 40 base pair (bp), DAT1 30 bp, DRD4 48 bp, and cannabinoid receptor type 1 (CNR1). Specifically, 669 healthy humans participated in a delayed recognition memory paradigm on two consecutive days. On the first day, male vs. female faces served as cues predicting an immediate monetary reward upon correct button presses. Subsequently, participants performed a remember/know recognition memory task on the same day and 1 day later. As predicted, reward increased accuracy and accelerated response times, which were modulated by DAT 30 bp. However, reward did not promote subsequent recognition memory performance and there was no interaction with any genotype tested here. Importantly, there were differential effects of genotype on declarative long-term memory independent of reward: (a) DAT1 40 bp was linked to the quality of memory with a more pronounced difference between recollection and familiarity in the heterozygous and homozygous 10-R as compared to homozygous 9-R; (b) DAT1 30 bp was linked to memory decay, which was most pronounced in homozygous 4-R; (c) DRD4 48 bp was linked to overall recognition memory with higher performance in the short allele group; and (d) CNR1 was linked to overall memory with reduced performance in the homozygous short group. These findings give new insights into how polymorphisms, which are related to dopaminergic neuromodulation, differentially affect long-term recognition memory performance.

Electrocortical indices of subjectively perceived confidence in episodic memory

Electrophysiological studies on recognition memory have identified several brain signals that are associated with subjective perceived confidence. However, the extent these brain signals reflect a generic process and are independent of the type of information recognized remains an open question. To address this issue, twenty-seven healthy volunteers performed an episodic memory task while their electro-encephalogram (EEG) was recorded. Participants encoded a set of abstract pictures, and subsequently rated their confidence on recognition decisions. Similar to results reported in previous studies using concrete words, we found retrieval-related theta power, FN400 and late positive component (LPC) effects. In contrast to previous studies using verbal material, a subsequent memory effect for encoding-related evoked theta power, sensitive to subjectively perceived memory confidence, was observed. Our findings suggest that brain signals that are associated with subjectively perceived confidence reflect specific encoding, but generic retrieval processes.

Individual differences in selective attention and scanning dynamics influence children's learning from relevant non-targets in a visual search task

Efficient selective attention is critical for engaging in task-oriented behavior but may also limit our processing of potentially meaningful, task-irrelevant details. Both older adults and younger children demonstrate poor selective attention skills but show increased processing of task-irrelevant information. This broader attention to non-targets can benefit learning among older adults when the non-target information is relevant to a primary learning goal. Although young children show similar patterns of attention to non-targets, it is unknown whether relevant non-targets similarly benefit their learning. This study examined the relationship between 4- to 8-year-old children's selective attention skills and their learning from incidental exposure to relevant non-targets. In Experiment 1, children completed an incidental encoding phase, followed by a visual search task and then a final recognition memory task. During the search task, participants identified a target within arrays containing 0, 5, 10, or 15 non-targets. Half of the images from the encoding phase appeared in the search as "relevant" non-targets, whereas the remainder never appeared during the search task. Participants showed better memory for images presented as relevant non-targets. However, children showed the largest memory benefit when efficient selective attention allowed for increased scanning of the relevant non-targets after target detection. Experiment 2 confirmed that children showed similarly efficient selective attention skills but no longer showed enhanced learning when they could not scan relevant non-targets following target detection. These results suggest that children's incidental learning from relevant non-targets is an active process that depends on how children use selective attention to engage in effective information gathering.

Distinctive encodings and the production effect: failure to retrieve distinctive encodings decreases recollection of silent items

Studies have shown that when aloud and silent items are studied together, silent items are remembered more poorly than when they are studied independently. We hypothesise that this cost to silent items emerges because, at test, participants search for memories of having said items aloud and when those memory searches fail, participants become uncertain about whether silent items were studied. This effect should be exaggerated if other unique distinctive encoding conditions are also included at study (e.g., mumbling, writing, typing, etc.). To test this prediction, we examined the impact of introducing mumbled, "important" (i.e., words that participants are told are the most important to remember), and mouthed words to a study list of aloud and silent words. Introducing mumbled and "important" words further impaired the recollection of silent items. Introducing mouthed items did not further impair the memorability of silent items because mouthing and speaking aloud are so similar and hence, are not fully unique from each other. The memorability of aloud items was unaffected in all conditions. These results suggest that participants search for distinctive encoding information at test, and only for items that fail those searches (i.e., silent items) do they lose confidence.

Retrieval Practice Improves Recollection-Based Memory Over a Seven-Day Period in Younger and Older Adults

Retrieving information improves subsequent memory performance more strongly than restudying. However, despite recent evidence for this retrieval practice effect (RPE), the temporal dynamics, age-related changes, and their possible interactions remain unclear. Therefore, we tested 45 young (18–30 years) and 41 older (50 + years) participants with a previously established RP paradigm. Specifically, subjects retrieved and restudied scene images on Day 1; subsequently, their recognition memory for the presented items was tested on the same day of learning and 7 days later using a remember/know paradigm. As main findings we can show that both young and older adults benefited from RP, however, the older participants benefited to a lesser extent. Importantly, the RPE was present immediately after learning on Day 1 and 7 days later, with no significant differences between time points. Finally, RP improved recollection rates more strongly than familiarity rates, independent of age and retrieval interval. Together, our results provide evidence that the RPE is reduced but still existing in older adults, it is stable over a period of seven days and relies more strongly on hippocampus-based recollection.

Scale-invariant Characteristics of Forgetting: Toward a Unifying Account of Hippocampal Forgetting across Short and Long Timescales

After over 100 years of relative silence in the cognitive literature, recent advances in the study of the neural underpinnings of memory-specifically, the hippocampus-have led to a resurgence of interest in the topic of forgetting. This review draws a theoretically driven picture of the effects of time on forgetting of hippocampus-dependent memories. We review evidence indicating that time-dependent forgetting across short and long timescales is reflected in progressive degradation of hippocampal-dependent relational information. This evidence provides an important extension to a growing body of research accumulated in recent years, showing that-in contrast to the once prevailing view that the hippocampus is exclusively involved in memory and forgetting over long timescales-the role of the hippocampus also extends to memory and forgetting over short timescales. Thus, we maintain that similar rules govern not only remembering but also forgetting of hippocampus-dependent information over short and long timescales.

Meta-analytic and functional connectivity evidence from functional magnetic resonance imaging for an anterior to posterior gradient of function along the hippocampal axis

There is considerable evidence from non-human animal studies that the anterior and posterior regions of the hippocampus have different anatomical connections and support different behavioural functions. Although there are some recent human studies using functional magnetic resonance imaging (fMRI) that have addressed this idea directly in the memory and spatial processing domains and provided support for it, there has been no broader meta-analysis of the fMRI literature to determine if there is consistent evidence for functional dissociations in anterior and posterior hippocampus across all of the different cognitive domains in which the hippocampus participates. The purpose of this review is to address this gap in our knowledge using three approaches. One approach involved PubMed searches to identify relevant fMRI papers reporting hippocampal activation during episodic encoding and retrieval, semantic retrieval, working memory, spatial navigation, simulation/scene construction, transitive inference, and social cognition tasks. The second was to use a large meta-analytic database (neurosynth) to find text terms and coactivation maps associated with the anterior and posterior hippocampal regions identified in the literature search. The third approach was to contrast the resting-state functional connectivity of the anterior and posterior hippocampal regions using a publicly available database that includes a large sample of adults. These three approaches provided converging evidence that not only are cognitive processes differently distributed along the hippocampal axis, but there also are distinct areas coactivated and functionally connected with the anterior and posterior segments. This anterior/posterior distinction involving multiple cognitive domains is consistent with the animal literature and provides strong support from fMRI for the idea of functional dissociations across the long axis of the hippocampus.

Probability of target recollection varies with target-lure relatedness under the dual process signal detection model

The ROC function plots hit and false alarm rates against one another. For item recognition the z-transformed ROC (Z-ROC) function is typically linear with slope less than one. The Dual Process Signal Detection (DPSD) and Unequal Variance Signal Detection (UVSD) models see the slope as reflecting the ratio of the lure and target evidence standard deviations. The DPSD model in addition sees the slope as co-varying with estimates of target recollection probability (R). This follows because the slope decreases with increases in the target evidence standard deviation which in turn increases with increases in the numbers of high evidence recollection items. However our results suggest that the lure evidence standard deviation, and thus the Z-ROC slope, can vary with factors seemingly unrelated to target recollection, posing problems for DPSD estimates of R. In word recognition the standard deviation of lure confidence ratings and the slope of the z-ROC function were larger with semantically related than unrelated lures. When the data for related and unrelated lures were fit separately, the standard two-parameter DPSD model, implausibly, set R lower for related than unrelated lures. The UVSD model, more plausibly, set the lure evidence standard deviation larger for related than unrelated lures.

Response bias, recollection, and familiarity in individuals with Highly Superior Autobiographical Memory (HSAM)

The current study focused on individuals with Highly Superior Autobiographical Memory (HSAM) and had two main objectives: 1) investigate whether HSAMs have increased recollection performance compared to controls, and 2) investigate whether HSAMs have a reliably different response bias than controls. While previous lab-based recognition tests have shown that HSAMs have normal memory performance, these tests were based on a mixture of both recollection and familiarity. Here, we employed recognition tests specifically designed to separate recollected responses from those based on familiarity. Additionally, we were interested in how HSAMs make their memory decisions. Several studies have shown a great deal of variability between individuals in their response bias. Here, individuals with HSAM and age- matched controls completed a remember/know and a source memory test. HSAMs behaved like controls in both overall and recollection-based memory discrimination. However, HSAMs showed a significantly more liberal response bias, endorsing more items as "old" than controls. These findings contribute to our understanding of how memory processes - especially those related to decision-making - function in those with superior memory abilities and may help elucidate how other (non-HSAM) memory experts make decisions.

Novelty Before or After Word Learning Does Not Affect Subsequent Memory Performance

In humans, exposure to novel images and exploration of novel virtual environments before the encoding of words improved subsequent memory performance. Animal studies revealed similar effects of novelty, both before and after learning, and could show that hippocampus-dependent dopaminergic neuromodulation plays an important role. Here, we further investigated the effects of novelty on long-term memory in humans using a novel paradigm employing short sequences of nature movies presented either before or at two time points after learning of unrelated words. Since novelty processing is associated with a release of dopamine into the hippocampus, we hypothesized that novelty exposure primarily affects hippocampus-dependent memory (i.e., recollection) but not hippocampus-independent memory (i.e., familiarity). We tested 182 healthy human subjects in three experiments including a word-learning task followed by a 1-day delayed recognition task. Importantly, participants were exposed to novel (NOV) or familiar movies (FAM) at three time points: (experiment 1) directly after encoding of the word list, (experiment 2) 15 min after encoding, (experiment 3) 15 min prior to encoding. As expected, novel movies were perceived as more interesting and led to better mood. During word recognition, reaction times were faster for remember as compared to familiarity responses in all three experiments, but this effect was not modulated by novelty. In contrast to our main hypothesis, there was no effect of novelty – before or after encoding – on subsequent word recognition, including recollection and familiarity scores. Therefore, an exposure to novel movies without an active task does not affect hippocampus-dependent and hippocampus-independent long-term recognition memory for words in humans.

Memory and cognition in schizophrenia

Episodic memory deficits are consistently documented as a core aspect of cognitive dysfunction in schizophrenia patients, present from the onset of the illness and strongly associated with functional disability. Over the past decade, research using approaches from experimental cognitive neuroscience revealed disproportionate episodic memory impairments in schizophrenia (Sz) under high cognitive demand relational encoding conditions and relatively unimpaired performance under item-specific encoding conditions. These specific deficits in component processes of episodic memory reflect impaired activation and connectivity within specific elements of frontal-medial temporal lobe circuits, with a central role for the dorsolateral prefrontal cortex (DLPFC), relatively intact function of ventrolateral prefrontal cortex and variable results in the hippocampus. We propose that memory deficits can be understood within the broader context of cognitive deficits in Sz, where impaired DLPFC-related cognitive control has a broad impact across multiple cognitive domains. The therapeutic implications of these findings are discussed.

The electrophysiology of subjectively perceived memory confidence in relation to recollection and familiarity

Subjectively perceived confidence is critically involved in distinguishing recollection from familiarity in episodic memory retrieval. However, the extent to which recollection and familiarity share similar electrophysiological processes associated with subjectively perceived memory confidence remains an open question. In addition, the role of memory encoding in subjectively perceived confidence during retrieval has not yet been investigated. To address these issues, an EEG study was performed in thirty healthy volunteers. During a memory task, participants encoded a subset of words while rating the words on pleasantness. Memory recognition and subjectively perceived confidence concerning these 'old' and additional 'new' words was tested. Results showed that during retrieval, correctly classifying an old item with high subjectively perceived confidence was associated with a parietal ERP and parietal theta power, while frontal theta activity was related to high-confident novelty processing. During the memory encoding phase, a parietal ERP and frontal theta oscillations were related to subsequent subjectively perceived memory confidence. Our findings provide the first evidence that subjectively perceived memory confidence is associated with distinct electrophysiological correlates during both memory encoding and retrieval.

Electrophysiological and behavioral evidence for attentional up-regulation, but not down-regulation, when encoding pictures into long-term memory

Visual long-term memory allows us to store a virtually infinite amount of visual information (Brady, Konkle, Alvarez, & Oliva in Proceedings of the National Academy of Sciences of the United States of America, 105(38), 14325-14329, 2008; Standing in Quarterly Journal of Experimental Psychology, 25(2), 207-222, 1973). However, our ability to encode new visual information fluctuates from moment to moment. In Experiment 1, we tested the hypothesis that we have voluntary control over these periodic fluctuations in our ability to encode representations into visual long-term memory using a precueing paradigm combined with behavioral and electrophysiological indices of memory encoding. We found that visual memory encoding can be up-regulated, but it was much more difficult, if not impossible, to down-regulate encoding on a trial-by-trial basis. In Experiment 2, we tested the hypothesis that voluntary up-regulation of visual memory encoding for an item incurs a cost to memory encoding of other items by manipulating the cueing probability. Here, we found that, although the cueing benefit was constant for both low (20%) and high (50%) cueing probabilities, the benefit in the high cueing probability condition came with the overall impairment of memory encoding. Taken together, our findings demonstrate that top-down control of visual long-term memory encoding may be primarily to prioritize certain memories, but this prioritization has a cost and should not be overused to avoid its negative consequences.

Episodic recognition memory and the hippocampus in Parkinson's disease: A review

Parkinson's disease is a progressive neurodegenerative disorder of aging. The hallmark pathophysiology includes the development of neuronal Lewy bodies in the substantia nigra of the midbrain with subsequent loss of dopaminergic neurons. These neuronal losses lead to the characteristic motor symptoms of bradykinesia, rigidity, and rest tremor. In addition to these cardinal motor symptoms patients with PD experience a wide range of non-motor symptoms, the most important being cognitive impairments that in many circumstances lead to dementia. People with PD experience a wide range of cognitive impairments; in this review we will focus on memory impairment in PD and specifically episodic memory, which are memories of day-to-day events of life. Importantly, these memory impairments severely impact the lives of patients and caregivers alike. Traditionally episodic memory is considered to be markedly dependent on the hippocampus; therefore, it is important to understand the exact nature of PD episodic memory deficits in relation to hippocampal function and dysfunction. In this review, we discuss an aspect of episodic memory called recognition memory and its subcomponents called recollection and familiarity. Recognition memory is believed to be impaired in PD; thus, we discuss what aspects of the hippocampus are expected to be deficient in function as they relate to these recognition memory impairments. In addition to the hippocampus as a whole, we will discuss the role of hippocampal subfields in recognition memory impairments.

Previously rewarding environments enhance incidental memory formation

Declarative memory performance is superior for items that were encoded in temporal proximity to reward delivery or expectancy. How reward-predicting contexts affect subsequent declarative memory formation in those contexts are, however, unknown. Using an ecological experimental setup in the form of a naturalistic driving simulator task, we examined the effect that previously rewarded environments may have on incidental memory formation. After driving in two distinct environments, one of which associated with monetary reward, participants drove again in the environments, which were embedded with unique images on billboards. A recognition test 24 h later demonstrated that incidental memory was superior for items presented in the reward-associated environment. These findings suggest that environmental cues imbued with incentive salience promote memory processes even in the absence of reward.

Exercise Similarly Facilitates Men and Women's Selective Attention Task Response Times but Differentially Affects Memory Task Performance

Previous research has found that acute, moderate-intensity physical exercise enhances selective attention and memory and that men and women show differential performance on tasks measuring these skills. Although exercise and participant sex have been examined separately, it remains unknown whether acute, moderate-intensity exercise differentially affects men and women’s selective attention and memory encoding and retrieval. Participants in the present study completed two 10-min sessions of either moderate-intensity exercise comprised of jumping rope alternating with walking in place or an active control protocol comprised of watching wellness videos alternating with walking in place. Each participant completed a selective attention task and a task assessing recognition and object location memory immediately after exercising. Exercise was related to overall faster performance during the selective attention task, with no differences in men and women’s performance. Women showed better recognition memory compared to men. Exercise specifically improved object location memory among men, but only among participants who completed the memory task second. These findings suggest that acute, moderate-intensity exercise differentially affects men and women’s memory, which may be related to complex interactions between exercise, sex hormones, and the neurotrophin BDNF.

The posterior parietal cortex and subjectively perceived confidence during memory retrieval

Functional neuroimaging studies suggest a role for the left angular gyrus (AG) in processes related to memory recognition. However, results of neuropsychological and transcranial magnetic stimulation (TMS) studies have been inconclusive regarding the specific contribution of the AG in recollection, familiarity, and the subjective experience of memory. To obtain further insight into this issue, 20 healthy right-handed volunteers performed a memory task in a single-blind within-subject controlled TMS study. Neuronavigated inhibitory repetitive TMS (rTMS) was applied over the left AG and the vertex in a randomized and counterbalanced order. Prior to rTMS participants were presented with a list of words. After rTMS participants were shown a second list of words and instructed to indicate if the word was already shown prior to rTMS ("old") or was presented for the first time ("new"). In addition, subjectively perceived memory confidence was assessed. Results showed that recollection was unaffected following inhibitory left AG rTMS. In contrast, rTMS over the left AG improved both familiarity and the subjectively perceived confidence of participants that demonstrated low baseline memory recognition. Our study highlights the importance of taking into account individual differences in experimental designs involving noninvasive brain stimulation.

Modulation of target recollection and recollection rejection networks due to retrieval facilitation and interference

To better understand neural recollection processing, we induced interference in target recollection by presenting related lures before their respective targets and facilitated recollection rejection of lures by presenting targets before their related lures. Target recollection following interference recruited visual and prefrontal cortices, showing that these regions support recollection when related information has disrupted target representations. Recollection rejection following target presentation recruited angular gyrus, indicating that this region supports recollection rejection when target representations are strong and highly accessible. Thus, recollection networks are sensitive to the accessibility of target representations that are affected by the presentation of related information during retrieval.

Recognition memory: Cellular evidence of a massive contribution of the LEC to familiarity and a lack of involvement of the hippocampal subfields CA1 and CA3

A highly debated issue in memory research is whether familiarity is supported by the parahippocampal region, especially the lateral (LEC) and the perirhinal (PER) cortices, or whether it is supported by the same brain structure as recollection: the hippocampus. One reason for this is that conflicting results have emerged regarding the contribution of the hippocampus to familiarity. This might stem from the lack of dissociation between hippocampal subfields CA1 and CA3 as these areas are involved to a different extent in processes which are pertinent to familiarity. Another reason is that empirical evidence for a contribution of the LEC is still missing. Furthermore, it is unclear whether the superficial and the deep layers of the LEC would equally contribute to this process as these layers are differentially recruited during memory retrieval which partly relies on familiarity. To identify the specific contribution of the LEC, CA1, and CA3, we imaged with cellular resolution activity in the brain of rats performing a version of a standard human memory task adapted to rats that yields judgments based on familiarity. Using this translational approach, we report that in striking contrast to CA1 and CA3, the LEC is recruited for familiarity-judgments and that its contribution is comparable to that of the PER. These results show for the first time that the LEC, specifically its deep layers, contributes to familiarity and constitute the first cellular evidence that the hippocampus does not, thus establishing that familiarity does not share the same neural substrate as recollection.

The influence of recollection and familiarity in the formation and updating of associative representations

Prior representations affect future learning. Little is known, however, about the effects of recollective or familiarity-based representations on such learning. We investigate the ability to reuse or reassociate elements from recollection- and familiarity-based associations to form new associations. Past neuropsychological research suggests that hippocampal, and presumably recollective, representations are more flexible than extra-hippocampal, presumably familiarity-based, representations. We therefore hypothesize that the elements of recollective associations, as opposed to familiarity-based representations, may be more easily manipulated and decoupled from each other, and facilitate the formation of new associations. To investigate this hypothesis we used the AB/AC learning paradigm. Across two recall studies we observed an advantage in learning AC word pairs if AB word pairs were initially recollected. Furthermore, AB word pairs were more likely to intrude during a final AC test if those AB word pairs were initially familiarity-based. A third experiment using a recognition version of the AB/AC paradigm ruled out the possibility that our findings were due to memory strength. Our results support the idea that elements in recollective associative traces may be more discretely coded, leading to their flexible use, whereas elements in familiarity-based associative traces are less flexible.

Revising recognition judgments during noisy recognition evidence accumulation: The dynamics of losses versus gains

Outside the laboratory, we sometimes revise our recognition judgments of others-realizing, for example, that we have accidentally failed to greet an acquaintance we just passed in the hallway. These recognition reversals have rarely been studied. Here, using a basic noisy-accumulation framework, we simulated recognition response reversals in which initial speeded recognition judgments were followed by an opportunity to revise the initial judgment. The simulation predictions were compared to empirical data from two experiments in which we gave participants the opportunity to revise each of their initial speeded recognition judgments. The speeded old-new responses were restricted to either 300-800 ms (Exp. 1) or 200-600 ms (Exp. 2) after each probe's onset, and the second response was self-paced in both experiments. The noisy-accumulation framework correctly anticipated three findings. First, gain rates (incorrect followed by correct responses) always exceeded loss rates (correct followed by incorrect responses). Second, despite being corrective, the raw gain rates exhibited a modest negative correlation with overall recognition skill. Third, when gain rates were conditioned on the opportunity to correct an initial error (conditional gain rate), they were then positively correlated with recognition skill but were less diagnostic than the conditional loss rates. Thus, the mechanics of noisy accumulation naturally predict that skilled recognizers will demonstrate infrequent corrective behavior but a high probability of correction, should an initial error occur.

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.

Forget all that nonsense: The role of meaning during the forgetting of recollective and familiarity-based memories

Memory can be divided into recollection and familiarity. Recollection is characterized as the ability to vividly re-experience past events, and is believed to be supported by the hippocampus, whereas familiarity is defined as an undifferentiated feeling of knowing or acquaintance, and is believed to be supported by extra-hippocampal regions, such as the perirhinal cortex. Recent evidence suggests that the neural architectures of the hippocampus and neocortex lead information in these regions being susceptible to different forgetting processes. We expand on these accounts and propose that the neocortex may be sensitive to the semantic content of a trace, with more meaningful traces being more easily retained. The hippocampus, in contrast, is not hypothesized to be influenced by semantics in the same way. To test this new account, we use a continuous-recognition paradigm to examine the forgetting rates words and nonwords that are either recollected or familiar. We find that words and nonwords that are recollected are equally likely to be forgotten over time. However, nonwords that are familiar are more likely to be forgotten over time than are words that are familiar. Our results support recent neuropsychologically-based forgetting theories of recollection and familiarity and provide new insight into how and why representations are forgotten over time.

Familiarity, but not recollection, supports the between-subject production effect in recognition memory

Five experiments explored the basis of the between-subjects production effect in recognition memory as represented by differences in the recollection and familiarity of produced (read aloud) and nonproduced (read silently) words. Using remember-know judgments (Experiment 1b) and a dual-process signal-detection approach applied to confidence ratings (Experiments 2b and 3), we observed that production influences familiarity but not recollection when manipulated between-subjects. This is in contrast to within-subject designs, which reveal a clear effect of production on both recollection and familiarity (Experiments 1a and 2a). Our findings resolve contention concerning apparent design effects: Whereas the within-subject production effect is subserved by separable recollective- and familiarity-based components, the between-subjects production effect is subserved by the familiarity-based component alone. Our findings support a role for the relative distinctiveness of production as a means of guiding recognition judgments (at least when manipulated within-subjects), but we also propose that production influences the strength of produced items, explaining the persistence of the effect in between-subjects designs. (PsycINFO Database Record

Stability of age-related deficits in the mnemonic similarity task across task variations

Several studies in our lab and others have demonstrated age-related declines in mnemonic discrimination during a recognition memory paradigm using repeated items, similar lures, and novel foils. In particular, older adults exhibit a shift in lure discriminability, identifying similar lures as old items at a greater rate than young adults. This shift likely reflects deficits in pattern separation processing as a result of underlying changes in the dentate gyrus of the hippocampus. Here, we explored whether alterations in the task design could rescue the age-related impairment or whether it was ubiquitous as one might expect if the neurobiological mechanisms were truly disturbed by typical aging. Despite overt instructions to study item details during encoding, we replicated the age-related deficit in mnemonic discrimination. We established reliable effects with short lists of stimuli and with repeated testing. Altering the task design from a study/test to a continuous recognition paradigm replicated the age-related shift in lure discrimination as well. Modifying the task to an old/new response (rather than old/similar/new) showed the same effect and a d' analysis showed that lure items were more akin to target items in older adults. Finally, we varied the test instructions in order to promote gist or veridical responses in the old/new task. Even these overt veridical test instructions did not ameliorate older adults' lure discrimination problems. Together, these findings demonstrate the robust nature of this age-related deficit and support the hypothesis that typical aging results in neurobiological changes that underlie this impairment.

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.

Modeling confidence and response time in associative recognition

Research examining models of memory has focused on differences in the shapes of ROC curves across tasks and has used these differences to argue for and against the existence of multiple memory processes. ROC functions are usually obtained from confidence judgments, but the reaction times associated with these judgments are rarely considered. The RTCON2 diffusion model for confidence judgments has previously been applied to data from an item recognition paradigm. It provided an alternative explanation for the shape of the z-ROC function based on how subjects set their response boundaries and these settings are also constrained by reaction times. In our experiments, we apply the RTCON2 model to data from associative recognition tasks to further test the model's ability to accommodate non-linear z-ROC functions. The model is able to fit and explain a variety of z-ROC shapes as well as individual differences in these shapes while simultaneously fitting reaction time distributions. The model is able to distinguish between differences in the information feeding into a decision process and differences in how subjects make responses (i.e., set decision boundaries and confidence criteria). However, the model is unable to fit data from a subset of subjects in these tasks and this has implications for models of memory.

Face recognition in schizophrenia: do individual and average ROCs tell the same story?

INTRODUCTION

Many studies have shown that recollection process is impaired in patients with schizophrenia, whereas familiarity is generally spared. However, in these studies, the Receiver Operating Characteristic (ROC) presented is average ROC likely to mask individual differences.

METHODS

In the present study using a face-recognition task, we computed the individual ROC of patients with schizophrenia and control participants. Each group was divided into two subgroups on the basis of the type of recognition processes implemented: recognition based on familiarity only and recognition based on familiarity and recollection.

RESULTS

The recognition performance of the schizophrenia patients was below that of the control participants only when recognition was based solely on familiarity. For the familiarity-alone patients, the score obtained on the Scale for the Assessment of Positive Symptoms (SAPS) was correlated with the variance of the old-face familiarity. For the familiarity-recollection patients, the score obtained on the Scale for the Assessment of Negative Symptoms (SANS) was correlated with the decision criterion and with the old-face recollection probability.

CONCLUSIONS

These results show that one cannot ascribe the impaired recognition observed in patients with schizophrenia to a recollection deficit alone. These results show that individual ROC can be used to distinguish between subtypes of schizophrenia and could serve as a basis for setting up specific cognitive remediation therapy for individuals with schizophrenia.

Process dissociation of familiarity and recollection in children: response deadline affects recollection but not familiarity

According to dual-process theories, recollection (slow and associated with contextual details) and familiarity (fast and automatic) are two independent processes underlying recognition memory. An adapted version of the process dissociation paradigm was used to measure recognition memory in 5-, 7-, and 11-year-olds and adults. In Experiment 1, it was found that 5-year-olds already recollect details of items (i.e., number). Recollection increased particularly between 5 and 7 years. Familiarity differed between 5 years and adulthood. In Experiment 2, under limited response time during retrieval, recollection was eliminated in 5-year-olds and reduced across all ages, whereas familiarity was left unaffected. Together, these findings are consistent with dual-process theories of recognition memory and provide support for two processes underlying recognition memory from a developmental perspective.