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The Penn Electrophysiology of Encoding and Retrieval Study (PEERS) aimed to characterize the behavioral and electrophysiological (EEG) correlates of memory encoding and retrieval in highly practiced individuals. Across five PEERS experiments, 300+ subjects contributed more than 7,000 memory testing sessions with recorded EEG data. Here we tell the story of PEERS: its genesis, evolution, major findings, and the lessons it taught us about taking a big scientific approach in studying memory and the human brain. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
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While previous work has shown a positive relationship between cognitive performance and lifestyle factors in younger adults, evidence for this relationship among middle-aged and older adults has been mixed. The current study aimed to further test the relationship among physical activity, sleep quality, and memory performance in middle-aged and older adults, and to test whether this relationship holds up during the COVID-19 pandemic. Our results showed that physical activity was associated with better sleep quality and better working memory performance, and better sleep quality was associated with better working memory and self-perceptions of everyday memory abilities. Additionally, we found that the effects of physical activity on working memory were partially mediated by sleep quality. While these effects were small and only correlational in nature, they lend further support to the notion that sleep quality and physical activity are beneficial to memory later in life, even during a global pandemic.
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Recent work has examined the interaction between space and time in memory search, but there is still limited understanding of this relationship. Here, we test the hypothesis that individuals can exert control over how time and space interact in response to subtle differences in task instructions. To test this hypothesis, we analyzed two experiments where participants completed two immediate free recall tasks, a verbal task involving words presented at a central location and a spatial task involving squares presented at different locations. Some participants were free to recall the words or locations spontaneously in any order they preferred. In contrast, another group was subtly biased toward temporal information by instructions to begin recall from the last presented item before recalling the remaining items in any order they wished. Replicating recent work, all conditions showed clear evidence that recall was organized along both the temporal and the spatial dimensions. Extending this work, we found that the subtle change in recall instructions increased the reliance on temporal information in the spatial recall task. Correlational analyses suggest that spatial and temporal information do not compete when participants search memory spontaneously. However, they do compete when instructions favor temporal information. These findings highlight that individuals can exert some cognitive control over how associative dimensions interact during memory search and emphasize the importance of incorporating such processes into theoretical models.
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Rememoração Mental , Percepção Espacial , Humanos , Rememoração Mental/fisiologia , Adulto Jovem , Adulto , Percepção Espacial/fisiologia , Percepção do Tempo/fisiologia , Masculino , Feminino , Fatores de Tempo , Função Executiva/fisiologia , Memória de Curto Prazo/fisiologiaRESUMO
Recent events are easy to recall, but they also interfere with the recall of more distant, non-recent events. In many computational models, non-recent memories are recalled by using the context associated with those events as a cue. Some models, however, do little to explain how people initially activate non-recent contexts in the service of accurate recall. We addressed this limitation by evaluating two candidate mechanisms within the Context-Maintenance and Retrieval model. The first is a Backward-Walk mechanism that iteratively applies a generate/recognize process to covertly retrieve progressively less recent items. The second is a Post-Encoding Pre-Production Reinstatement (PEPPR) mechanism that formally implements a metacognitive control process that reinstates non-recent contexts prior to retrieval. Models including these mechanisms make divergent predictions about the dynamics of response production and monitoring when recalling non-recent items. Before producing non-recent items, Backward-Walk cues covert retrievals of several recent items, whereas PEPPR cues few, if any, covert retrievals of that sort. We tested these predictions using archival data from a dual-list externalized free recall paradigm that required subjects to report all items that came to mind while recalling from the non-recent list. Simulations showed that only the model including PEPPR accurately predicted covert recall patterns. That same model fit the behavioral data well. These findings suggest that self-initiated context reinstatement plays an important role in recall of non-recent memories and provides a formal model that uses a parsimonious non-hierarchical context representation of how such reinstatement might occur.
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Rememoração Mental , Metacognição , Humanos , Rememoração Mental/fisiologia , Sinais (Psicologia)RESUMO
A key assumption of some leading memory theories is that information about the relative order of events is automatically encoded whenever memories are formed and automatically retrieved whenever events are remembered. This information is often used to guide memory search: Remembering one event tends to trigger the retrieval of other events previously experienced nearby in time (temporal contiguity effect). The retrieved context framework attributes this temporal contiguity effect to automatic encoding and retrieval processes, predicting temporal contiguity even in incidental encoding and implicit retrieval. There is strong evidence of temporal contiguity following incidental encoding, but does the prediction hold for implicit retrieval? In this experiment, we tested the framework's predictions for recall and repetition priming. Across 30 trials, undergraduates ([Formula: see text]) read a series of words aloud as they appeared onscreen. In each trial, two words were repeated (cue and target), initially separated by |lag[Formula: see text] 1, 2, or 5. On their second presentation, the cue word was presented first, immediately followed by the target word. We found a strong temporal contiguity effect in a surprise free recall test, replicating previous work with explicit retrieval. For implicit retrieval, we compared repetition priming (how quickly subjects began reading a word on its first versus second presentation) for cue and target words. Repeating a cue word enhanced repetition priming for its associated target word, and this effect varied with the initial lag between the cue and target. These results support theories that assume temporal information is encoded and retrieved automatically.
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The transformation of experiences into meaningful events and memories is intertwined with the notion of time. Temporal perception can influence, and be influenced by, segmenting continuous experience into meaningful events. Episodic memories formed from these events become associated with temporal information as well. However, it is less clear how temporal perception contributes to structuring events and organizing memory: whether it plays a more active or passive role, and whether this temporal information is encoded initially during perception or influenced by retrieval processes. To address these questions, we examined how event segmentation influences temporal representations during initial perception and memory retrieval, without testing temporal information explicitly. Using a neural measure of temporal context extracted from scalp electroencephalography in human participants (N = 170), we found reduced temporal context similarity between studied items separated by an event boundary when compared to items from the same event. Furthermore, while participants freely recalled list items, neural activity reflected reinstatement of temporal context representations from the study phase, including temporal disruption. A computational model of episodic memory, the context maintenance and retrieval (CMR) model, predicted these results, and made novel predictions regarding the influence of temporal disruption on recall order. These findings implicate the impact of event structure on memory organization via temporal representations, underscoring the role of temporal information in event segmentation and episodic memory. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Memória Episódica , Percepção do Tempo , Humanos , Rememoração Mental , Eletroencefalografia/métodosRESUMO
Memory tends to be better when items are processed for their meaning (deep processing) rather than their perceptual features (shallow processing). This levels of processing (LOP) effect is well-replicated and has been applied in many settings, but the mechanisms involved are still not well understood. The temporal contiguity effect (TCE), the finding that recalling one event often triggers recall of another event experienced nearby in time, also predicts memory performance. This effect has given rise to several competing theories with specific contiguity-generating mechanisms related to how items are processed. Therefore, studying how LOP and the TCE interact may shed light on the mechanisms underlying both effects. However, it is unknown how LOP and the TCE interact-various theories make differing predictions. In this preregistered study, we tested predictions of three theoretical explanations: accounts which assume temporal information is automatically encoded, accounts based on a trade-off between item and order information, and accounts which emphasize the importance of strategic control processes. Participants completed an immediate free recall task where they either engaged in deep processing, shallow processing, or no additional task while studying each word. Recall and the TCE were highest for no-task lists and greater for deep than shallow processing. Our results support theories which assume temporal associations are automatically encoded and those which emphasize strategic control processes. Both perspectives should be considered in theory development. These findings also suggest temporal information may contribute to better recall under deeper processing with implications for determining which situations benefit from deep processing.
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Memória de Curto Prazo , Rememoração Mental , Humanos , TempoRESUMO
The present study is the first to examine individual differences in long-term memory, arousal dysregulation, and intensity of attention within the same experiment. Participants (N = 106) completed 28 lists of an immediate free-recall task while their pupil diameter was recorded via an eye-tracker during the encoding period. Two main pupillary measures were extracted: intraindividual variability in pre-list pupil diameter and evoked pupillary responses during item encoding. Variability in pre-list pupil diameter served as a measure of arousal dysregulation, and evoked pupillary responses served as a measure of intensity of attention. Based on prior work, we hypothesized that there would be a positive association between intensity of attention and recall ability, and that there would be a negative association between arousal dysregulation and recall ability. Collectively these two measures accounted for 19% of interindividual variance in recall, with 5% attributable uniquely to intensity of attention and 12% attributable uniquely to arousal regulation. The findings demonstrate that there are sources of individual differences in long-term memory that can be revealed via pupillometry, notably the amount of effort deployed during item encoding and the degree to which people exhibit dysregulated arousal. Both findings are consistent with recent theorizing regarding the role of the locus coeruleus (LC)-norepinephrine (NE) system's role in goal-directed cognition. Specifically, the LC governs both moment-to-moment arousal and NE release to cortical regions subserving cognitive processing. Among people for whom this system operates most optimally, long-term memory retention is superior.
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Individualidade , Pupila , Atenção/fisiologia , Cognição/fisiologia , Humanos , Memória de Longo Prazo , Norepinefrina/fisiologia , Pupila/fisiologiaRESUMO
People with schizophrenia experience episodic memory impairments that have been theorized to reflect deficits in processing context (e.g., spatio-temporal features tied to a specific event). Although past research has reported episodic memory impairments in young people at-risk for schizophrenia, the extent to which these impairments reflect context processing deficits remains unknown. We addressed this gap in the literature by examining whether children and adolescents at risk for schizophrenia exhibit context processing deficits during free recall, a memory task with high contextual demands. Our sample included three groups (N = 58, 9-16 years old) varying in risk for schizophrenia:16 high-risk, unaffected first-degree relatives of patients with schizophrenia, bipolar disorder, and/or schizoaffective disorder, 22 clinical control participants with a comorbid disorder (ADHD and/or an anxiety disorder), and 20 healthy control participants. Participants first completed a free recall task and then completed a recognition memory task. Based on established theories of episodic memory, we assumed that context processing played a more pivotal role in free recall than recognition memory. Consequently, if schizophrenia risk is associated with context processing deficits, then memory impairment should be present in free recall measures that are most sensitive to context processing (i.e., recall accuracy and temporal contiguity). Consistent with this prediction, free recall accuracy and temporal contiguity were lower for the high-risk group than the healthy controls, whereas recognition memory was comparable across groups. These findings suggest that episodic memory impairments associated with schizophrenia in unaffected, first-degree relatives may reflect context processing deficits.
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The temporal contiguity effect (TCE) is the tendency for the recall of one event to cue recall of other events originally experienced nearby in time. Retrieved context theory proposes that the TCE results from fundamental properties of episodic memory: binding of events to a drifting context representation during encoding and the reinstatement of those associations during recall. If these processes are automatic, the TCE should not be dependent on any encoding strategy and should, in fact, be present regardless of encoding intentionality. Here, we ask whether this theory is compatible with recent findings that the TCE is dramatically reduced under incidental encoding, even though memory accuracy is only modestly reduced. We begin by attempting to replicate this finding in a new large-scale study with over 5,000 participants in which we manipulated encoding intentionality between participants in both delayed free recall and continual distractor free recall. A small, but reliable, TCE was observed in all conditions, although the effect was dramatically reduced in incidental encoding. In a simulation study, we demonstrated that retrieved context theory can simultaneously account for both overall recall and the strength of the TCE in incidental encoding conditions. Additional analyses revealed that the incidental TCE is not an artifact of theoretically uninteresting factors, such as recency, and is consistent with being generated by the core contextual dynamics of retrieved context theory. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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Memória Episódica , Rememoração Mental , Humanos , TempoRESUMO
Space and time are both essential aspects of human episodic memory. Yet, behavioral studies into the dynamics of recall have focused more on time than space. For instance, it is now well known that temporally contiguous events are more likely to be subsequently recalled than temporally remote events, as measured by the lag-conditional response probability (lag-CRP), which represents the probability of recalling item i + lag after recalling item i. The present study administered both verbal and spatial delayed free recall (DFR) tasks to a sample of 168 participants in order to measure lag-CRPs along both spatial and temporal associative dimensions. Whereas only the temporal lag-CRP could be measured in the verbal DFR task, both temporal and spatial lag-CRPs could be measured in the spatial DFR task. As expected, the results obtained in the verbal DFR task indicated the typical temporal contiguity effect. More importantly, the results obtained in the spatial DFR task indicated significant contiguity effects along both associative dimensions, and the spatial contiguity effect was found to be significantly larger than the temporal contiguity effect. In addition, the relatively small temporal contiguity effect observed in the spatial DFR task was also found to be significantly smaller than the temporal contiguity effect observed in the verbal DFR task. Altogether, the present findings provided novel evidence that spatial and temporal proximity can both cue sequential dependencies between successive recalls. As such, retrieved context models of episodic memory should be expanded to include spatial context as well as temporal context.
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Memória Episódica , Humanos , Rememoração Mental , Probabilidade , TempoRESUMO
The electrophysiological evidence for suppression to date primarily draws upon traditional retrieval-induced forgetting and Think/No-Think paradigms, which involve strategic and intentional restriction of thought. Here event-related potential (ERP) signatures of suppression were examined using a novel task, which unlike traditional paradigms, does not include an initial priming step or intentional thought restraint. Participants were instructed to verbally generate semantically related responses to cue words (e.g., "PIZZA"), and unrelated responses to others. According to an inhibitory account of interference resolution, semantic competition from automatically activated target words must be resolved in order to generate an unrelated response, whereas no resolution is required for generating related responses. In a subsequent phase, accessibility for target words (e.g., "PEPPERONI") that required suppression, words that did not require suppression, as well as new control words was measured using a lexical decision task. We observed a sustained late positivity for unrelated responses in the generation task, and early negative amplitudes of suppressed items in the lexical decision task. These findings are consistent with inhibitory mechanisms operating at retrieval to suppress competitors and show that such processes operate on automatically activated items that are not presented in the context of an experiment, representative of retrieval situations that occur in everyday life.
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Fenômenos Eletrofisiológicos/fisiologia , Inibição Psicológica , Rememoração Mental/fisiologia , Adolescente , Adulto , Aprendizagem por Associação/fisiologia , Sinais (Psicologia) , Eletroencefalografia , Potenciais Evocados/fisiologia , Feminino , Humanos , Idioma , Masculino , Memória/fisiologia , Tempo de Reação/fisiologia , Semântica , Adulto JovemRESUMO
Longitudinal designs must deal with the confound between increasing age and increasing task experience (i.e., retest effects). Most existing methods for disentangling these factors rely on large sample sizes and are impractical for smaller scale projects. Here, we show that a measurement burst design combined with a model of retest effects can be used to study age-related change with modest sample sizes. A combined model of age-related change and retest-related effects was developed. In a simulation experiment, we show that with sample sizes as small as n = 8, the model can reliably detect age effects of the size reported in the longitudinal literature while avoiding false positives when there is no age effect. We applied the model to data from a measurement burst study in which eight subjects completed a burst of seven sessions of free recall every year for five years. Six additional subjects completed a burst only in years 1 and 5. They should, therefore, have smaller retest effects but equal age effects. The raw data suggested slight improvement in memory over five years. However, applying the model to the yearly-testing group revealed that a substantial positive retest effect was obscuring stability in memory performance. Supporting this finding, the control group showed a smaller retest effect but an equal age effect. Measurement burst designs combined with models of retest effects allow researchers to employ longitudinal designs in areas where previously only cross-sectional designs were feasible.
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We examined oscillatory power in electroencephalographic recordings obtained while younger (18-30 years) and older (60+ years) adults studied lists of words for later recall. Power changed in a highly consistent way from word-to-word across the study period. Above 14 Hz, there were virtually no age differences in these neural gradients. But gradients below 14 Hz reliably discriminated between age groups. Older adults with the best memory performance showed the largest departures from the younger adult pattern of neural activity. These results suggest that age differences in the dynamics of neural activity across an encoding period reflect changes in cognitive processing that may compensate for age-related decline.
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Encéfalo/fisiologia , Cognição/fisiologia , Eletroencefalografia , Transtornos da Memória/fisiopatologia , Rememoração Mental/fisiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/fisiologia , Fenômenos Eletrofisiológicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Adulto JovemRESUMO
Atkinson and Shiffrin (1968) argued that performance on any memory task reflects the combined influence of both the fixed structure of the memory system and control processes tailored to the specific task. We investigated the role of control processes in governing the temporal contiguity and semantic contiguity effects in free recall-tendencies to organize recall based on proximity in the study list and pre-existing semantic associations. Subjects studied lists that contained four "clusters", each composed of four semantically associated words but presented in random order such that associates were not in adjacent serial positions. Subjects were given either standard free-recall instructions, instructions to focus on order-based associations (i.e., the original order of presentation), or meaning-based associations (i.e., pre-existing semantic relationships). Replicating previous work, lists with strong semantic relationships resulted in a reduced overall temporal contiguity effect when recalled under standard free-recall instructions. However, under meaning-based recall instructions, the temporal contiguity effect was nearly eliminated. Detailed analyses of within-cluster transitions and an order reconstruction task revealed that temporal information was encoded, but control processes prevented it from dominating memory search. These results point to a need for more empirical work exploring how control processes change recall dynamics and for more theoretical work modeling the computational basis of these processes.
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Associação , Memória Episódica , Rememoração Mental/fisiologia , Adulto , Feminino , Humanos , Masculino , Semântica , Fatores de Tempo , Adulto JovemRESUMO
Some memories are linked such that recalling one can trigger the retrieval of another. What determines which memories are linked? Some models predict that simply occurring close together in time is sufficient for links to form between memories. A competing theory suggests that temporal proximity is generally not sufficient, and existing evidence for such links is an artifact of using chainlike lists of items in artificial laboratory tasks. To test these competing accounts, we asked subjects to recall news stories that they had encountered over the past 2 years (Experiment 1) or 4 months (Experiment 2). In both experiments, subjects showed a strong bias to successively recall stories that appeared in the news within days of each other-even after accounting for the fact that stories that occur close in time tend to be semantically related. By moving beyond laboratory tasks, this research solidifies the foundation of contemporary memory theory.
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Memória Episódica , Rememoração Mental/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de TempoRESUMO
Previous attempts to understand the neurocognitive mechanisms underlying attention-deficit/hyperactivity disorder (ADHD) may be limited by the tendency to focus exclusively on "externally directed cognition" (EDC) while ignoring "internally directed cognition" (IDC; Dixon, Fox, & Christoff, 2014. There is clear evidence that ADHD reflects deficiencies in EDC because of weaknesses in modulatory, motivational, and cognitive control constructs, but little is currently known about the integrity of IDC in ADHD. In the present study, we used a verbal episodic memory task involving immediate free recall to assess the integrity of EDC and IDC in a sample of 111 adolescents, 50 with study-confirmed diagnoses of ADHD and 61 without. The ADHD group was found to have significantly worse scores on outcomes that depend on EDC during encoding (serial position), and significantly better scores on outcomes that depend on IDC during retrieval (lag-conditional response probabilities). In addition, model parameters estimating the contribution of EDC and IDC processes were fit to these data using the retrieved context model of memory search. The model suggested that, during encoding, the ADHD group had slower mental context drift, indicative of weaker externally directed attention to the list items, as well as deficiencies in their ability to allocate and sustain attention when the study list first appeared. During retrieval, in contrast, the model suggested that the ADHD group had faster mental context drift indicative of stronger internally directed attention to retrieved context. These findings provide novel evidence that ADHD reflects impaired EDC and enhanced IDC, and they reinforce the clinical relevance of distinguishing EDC and IDC in future studies. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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Transtorno do Deficit de Atenção com Hiperatividade/psicologia , Atenção/fisiologia , Memória de Curto Prazo/fisiologia , Adolescente , Análise de Variância , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Criança , Cognição/fisiologia , Feminino , Humanos , Masculino , Memória Episódica , Motivação/fisiologiaRESUMO
Contiguity is one of the major predictors of recall dynamics in human episodic memory. But there are many competing theories of how the memory system gives rise to contiguity. Here we provide a set of benchmark findings for which any such theory should account. These benchmarks are drawn from a review of the existing literature as well as analyses of both new and archival data. They include 34 distinct findings on how various factors including individual and group differences, task parameters, and type of stimuli influence the magnitude of the contiguity effect. We will see that contiguity is observed in a range of tasks including recognition, paired associates, and autobiographical recall and across a range of time scales including minutes, days, weeks, and years. The broad pattern of data point toward a theory in which contiguity arises from fundamental memory mechanisms that encode and search an approximately time scale invariant representation of temporal distance.
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Memória Episódica , Rememoração Mental , Tempo , Humanos , Teoria PsicológicaRESUMO
We assessed age differences in the ability to resolve competition for figural status in stationary displays using small, enclosed, symmetrical silhouettes that participants classified as depicting "novel" or "familiar" shapes. The silhouettes were biased such that the inside was perceived as the shaped figure, and the outside was perceived as a shapeless ground. The critical manipulation was whether a portion of a meaningful object was suggested on the outside of the border of some of the novel silhouettes but not others (M+Ground and M-Ground novel silhouettes, respectively). This manipulation was intended to induce greater inhibitory competition for figural status from the groundside in M+Ground silhouettes than M-Ground silhouettes. In previous studies, young adults classified M+Ground silhouettes as "novel" faster than M-Ground silhouettes (Trujillo, Allen, Schnyer, & Peterson, 2010), suggesting that young adults may recruit more inhibition to resolve figure-ground when there is more competition. We replicated this effect with young adults in the present study, but older adults showed the opposite pattern and were less accurate in classifying M+Ground than M-Ground silhouettes. These results extend the evidence for inhibitory deficits in older adults to figure assignment in stationary displays. The (M+Ground - M-Ground) RT differences were evident in observers' longest responses, consistent with the hypothesis that inhibitory deficits are evident when the need for inhibition is substantial.
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Envelhecimento/fisiologia , Cognição/fisiologia , Percepção de Forma/fisiologia , Inibição Psicológica , Reconhecimento Visual de Modelos/fisiologia , Idoso , Feminino , Humanos , Masculino , Estimulação Luminosa , Adulto JovemRESUMO
We develop a novel, computationally explicit, theory of age-related memory change within the framework of the context maintenance and retrieval (CMR2) model of memory search. We introduce a set of benchmark findings from the free recall and recognition tasks that include aspects of memory performance that show both age-related stability and decline. We test aging theories by lesioning the corresponding mechanisms in a model fit to younger adult free recall data. When effects are considered in isolation, many theories provide an adequate account, but when all effects are considered simultaneously, the existing theories fail. We develop a novel theory by fitting the full model (i.e., allowing all parameters to vary) to individual participants and comparing the distributions of parameter values for older and younger adults. This theory implicates 4 components: (a) the ability to sustain attention across an encoding episode, (b) the ability to retrieve contextual representations for use as retrieval cues, (c) the ability to monitor retrievals and reject intrusions, and (d) the level of noise in retrieval competitions. We extend CMR2 to simulate a recognition memory task using the same mechanisms the free recall model uses to reject intrusions. Without fitting any additional parameters, the 4-component theory that accounts for age differences in free recall predicts the magnitude of age differences in recognition memory accuracy. Confirming a prediction of the model, free recall intrusion rates correlate positively with recognition false alarm rates. Thus, we provide a 4-component theory of a complex pattern of age differences across 2 key laboratory tasks.