Characterizing adult age differences in the initiation and organization of retrieval: A further investigation of retrieval dynamics in dual-list free recall

Individual and Age Differences in Item and Context Memory

We investigated whether individuals who are good at recognizing previously presented items are also good at recognizing the context in which items were presented. We focused specifically on whether the relation between item recognition and context recognition abilities differs in younger and older adults. It has been hypothesized that context memory declines more rapidly in older adults due to an age-related deficit in associative binding or recollection. To test this hypothesis, younger and older adults were asked to remember lists of names and objects, as well as the context (i.e. their size, location, and color) that accompanied those items. Following presentation of each list, recognition tests for items and context were administered. Confirmatory factor analysis (CFA) models analyzing both item and context scores together provided no evidence of separate factors for item and context memory. Instead, the best-fitting model separated performance by item-type, regardless of context, and no differences were found in the structure of these abilities in younger and older adults. These findings are consistent with the limited previous latent variable research on context memory in aging suggesting that there is no context recognition memory ability separable from item memory in younger nor older adults. Instead, individual differences in recognition memory abilities may be specific to the domain of the studied stimulus.

PEPPR: A post-encoding pre-production reinstatement model of dual-list free recall

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.

Adult age differences in subjective context retrieval in dual-list free recall

Age-related episodic memory deficits imply that older and younger adults differentially retrieve and monitor contextual features that indicate the source of studied information. Such differences have been shown in subjective reports during recognition and cued recall as well as process estimates derived from computational models of free recall organisation. The present study extends the subject report method to free recall to characterise age differences in context retrieval and monitoring, and to test assumptions from a context-based computational model. Older and younger adults studied two lists of semantically related words and then recalled from only the first or second list. After each recall, participants indicated their subjective context retrieval using remember/know judgments. Compared to younger adults, older adults showed lower recall accuracy and subjective reports of context retrieval (i.e., remember judgments) that were less specific to correct recalls. These differences appeared after first-recall attempts. Recall functions conditioned on serial positions were more continual across correct recalls from target lists and intrusions from non-target lists for older than younger adults. Together with other analyses of context retrieval and monitoring reported here, these findings suggest that older adults retrieved context less distinctively across the recall period, leading to greater perceived similarity for temporally contiguous lists.

Performance on the processing portion of complex working memory span tasks is related to working memory capacity estimates

Individual differences in working memory capacity (WMC) have long been known to relate to performance in domains outside of WM, including attentional control, long-term memory, problem-solving, and fluid intelligence to name a few. Complex span WM tasks, composed of a processing component and a storage component, are often used to index WMC in these types of investigations. Capacity estimates are derived from performance on the storage component only, while processing performance is often largely ignored. Here, we explore the relationship between processing performance and WMC in a large dataset for each of three complex span tasks to better characterize how the components of these tasks might be related. We provide evidence that enforcing an 85% or better accuracy criterion for the processing portion of the task results in the removal of a disproportionate number of individuals exhibiting lower WMC estimates. We also find broad support for differences in processing task performance, characterized according to both accuracy and reaction time metrics, as a function of WMC. We suggest that researchers may want to include processing task performance measures, in addition to capacity estimates, in studies using complex span tasks to index WMC. This approach may better characterize the relationships between complex span task performance and performance in disparate domains of cognition.

Spontaneous Distractor Reactivation With Age: Evidence for Bound Target-Distractor Representations in Memory

Reduced attentional control with age is associated with the processing and maintenance of task-irrelevant information in memory. Yet the nature of these memory representations remains unclear. We present evidence that, relative to younger adults (n = 48), older adults (n = 48) both (a) store simultaneously presented target and irrelevant information as rich, bound memory representations and (b) spontaneously reactivate irrelevant information when presented with previously associated targets. In a three-stage implicit reactivation paradigm, re-presenting a target picture that was previously paired with a distractor word spontaneously reactivated the previously associated word, making it become more accessible than an unreactivated distractor word in a subsequent implicit memory task. The accessibility of reactivated words, indexed by priming, was also greater than the degree of distractor priming shown by older adults in a control condition (n = 48). Thus, reduced attentional control influences the processing and representation of incoming information.

Interpolated retrieval effects on list isolation: Individual differences in working memory capacity

We examined the effects of interpolated retrieval from long-term memory (LTM) and short-term memory (STM) on list isolation in dual-list free recall and whether individual differences in working memory capacity (WMC) moderated those effects. Ninety-seven subjects completed study-test trials that included two study lists separated by either an exemplar generation task (LTM retrieval) or a two-back task (STM retrieval). Subjects then completed an externalized free recall task that allowed for the examination of response accessibility and monitoring. Individual differences in WMC were assessed using three complex span tasks: operation span, reading span, and rotation span. Correct recall and intratrial intrusion summary scores showed no effect of interpolated retrieval on either response accessibility or monitoring. However, serial-position curves for correct recall of List 1 showed larger primacy in the two-back than in the exemplar generation task for high-WMC subjects. We interpreted these results from a context change perspective, as showing that interpolated LTM retrieval accelerated context change for subjects who processed the context more effectively. We consider the implications of these findings for models of memory.

[Analysis of intrusion errors in free recall]

Extra-list intrusion errors during five trials of the eight-word list-learning task of the Amsterdam Dementia Screening Test (ADST) were investigated in 823 consecutive psychogeriatric patients (87.1% suffering from major neurocognitive disorder). Almost half of the participants (45.9%) produced one or more intrusion errors on the verbal recall test. Correct responses were lower when subjects made intrusion errors, but learning slopes did not differ between subjects who committed intrusion errors and those who did not so. Bivariate regression analyses revealed that participants who committed intrusion errors were more deficient on measures of eight-word recognition memory, delayed visual recognition and tests of executive control (the Behavioral Dyscontrol Scale and the ADST-Graphical Sequences as measures of response inhibition). Using hierarchical multiple regression, only free recall and delayed visual recognition retained an independent effect in the association with intrusion errors, such that deficient scores on tests of episodic memory were sufficient to explain the occurrence of intrusion errors. Measures of inhibitory control did not add significantly to the explanation of intrusion errors in free recall, which makes insufficient strength of memory traces rather than a primary deficit in inhibition the preferred account for intrusion errors in free recall.

Adult age differences in production and monitoring in dual-list free recall

The present experiment examined adult age differences in the production and monitoring of responses in dual-list free recall. Younger and older adults studied 2 lists of unrelated words and were instructed to recall from List 1, List 2, or List 1 and List 2. An externalized free recall procedure required participants to: (a) report all responses that came to mind while recalling from specific lists, (b) classify responses as correct or incorrect, and (c) provide confidence judgments for their accuracy classifications. Relative to younger adults, older adults showed a monitoring deficit by misclassifying proportionally more responses and discriminating more poorly between correct and incorrect responses in their confidence judgments. This deficit was especially pronounced under conditions of retroactive interference that occurred when participants recalled from List 1 only. A comparison of retrieval dynamics for all responses produced and for those that participants were reasonably confident were correct provided information about age differences in preretrieval context reinstatement and postretrieval monitoring of retrieved context. One noteworthy finding was that total production when recalling from List 1 showed that List 2 responses remained more accessible across the first several retrieval attempts for older than younger adults, which indicated a substantial age difference in the ability to reinstate List 1 context. Overall, the present findings provide a nuanced characterization of age differences in the operation of production and monitoring mechanisms under conditions of proactive and retroactive interference that can inform models of free recall. (PsycINFO Database Record