Working memory for item and temporal information in younger and older adults

Two experiments examined age differences in mechanisms hypothesized to affect activation of item and temporal information in working memory. Activation levels were inferred from the ability to reject n-back lures matching items in different temporal positions. Information with the least decay had a performance advantage over less recent information, but was susceptible to the same temporal context errors found in all adjacent-to-target lure positions. Lures most distant from the current item showed a performance rebound. The pattern of increased magnitudes of age effects at adjacent-to-target positions indicated a reduction in older adults' working memory for temporal context information above and beyond item memory declines. Results overall support the emphasis on context information as a critical factor in working memory and cognitive aging.     

Does survival context enhance memory for source? A within-subjects comparison

ABSTRACT

Nairne, Thompson, and Pandeirada [2007. Adaptive memory: Survival processing enhances retention. Journal of Experimental Psychology: Learning, Memory, and Cognition, 33, 263–273] demonstrated that processing words according to their relevance to a survival scenario enhanced their subsequent retrieval in recall and recognition tasks compared to a variety of control scenarios. From an adaptive perspective, it is maintained that processing words in a survival context should also enhance memory for source; however, evidence in the literature is rather mixed regarding a survival context advantage for source memory. In the current study, we conducted four experiments to systematically investigate the survival advantage in source memory, when the context itself is the source, with both recall (Experiments 1A and 1B) and recognition tests (Experiments 2A and 2B). Results showed a survival advantage for item memory over the control contexts in all experiments. The survival context advantage was not extended to source memory performance in Experiment 1A. Results from all other experiments, however, indicated a survival context advantage for both item and source memory. Findings are discussed in relation to possible proximate mechanisms underlying the survival processing effect.     

Children’s Memory for Temporal Information: The Roles of Temporal Language and Executive Function

Abstract

The ability to recall the temporal order of events develops much more slowly than the ability to recall facts about events. To explore what processes facilitate memory for temporal information, we tested 3- to 6-year-old children (N?=?40) for immediate memory of the temporal order of events from a storybook, using a visual timeline task and a yes/no recognition task. In addition, children completed tasks assessing their understanding of before and after and the executive functions of inhibition using the Day/Night Stroop task and cognitive shifting using the Dimensional Change Card Sort (DCCS) task. Older children (Mage?=?69.25?months) outperformed younger children (Mage?=?52.35?months) on all measures; however, the only significant predictor of memory for the temporal ordering of events was cognitive shifting. The findings suggest that the difficulty in memory for temporal information is related to development of a general cognitive ability, as indexed by the DCCS, rather than specific temporal abilities.     

Effects of Age on the Temporal Organization of Working Memory in Deaf Signers

ABSTRACT

Deaf native signers have a general working memory (WM) capacity similar to that of hearing non-signers but are less sensitive to the temporal order of stored items at retrieval. General WM capacity declines with age, but little is known of how cognitive aging affects WM function in deaf signers. We investigated WM function in elderly deaf signers (EDS) and an age-matched comparison group of hearing non-signers (EHN) using a paradigm designed to highlight differences in temporal and spatial processing of item and order information. EDS performed worse than EHN on both item and order recognition using a temporal style of presentation. Reanalysis together with earlier data showed that with the temporal style of presentation, order recognition performance for EDS was also lower than for young adult deaf signers. Older participants responded more slowly than younger participants. These findings suggest that apart from age-related slowing irrespective of sensory and language status, there is an age-related difference specific to deaf signers in the ability to retain order information in WM when temporal processing demands are high. This may be due to neural reorganisation arising from sign language use. Concurrent spatial information with the Mixed style of presentation resulted in enhanced order processing for all groups, suggesting that concurrent temporal and spatial cues may enhance learning for both deaf and hearing groups. These findings support and extend the WM model for Ease of Language Understanding.     

Local context effects during emotional item directed forgetting in younger and older adults

This paper explored the differential sensitivity young and older adults exhibit to the local context of items entering memory. We examined trial-to-trial performance during an item directed forgetting task for positive, negative, and neutral (or baseline) words each cued as either to-be-remembered (TBR) or to-be-forgotten (TBF). This allowed us to focus on how variations in emotional valence (independent of arousal) and instruction (TBR vs. TBF) of the previous item (trial n-1) impacted memory for the current item (trial n) during encoding. Different from research showing impairing effects of emotional arousal, both age groups showed a memorial boost for stimuli when preceded by items high in positive or negative valence relative to those preceded by neutral items. This advantage was particularly prominent for neutral trial n items that followed emotional items suggesting that, regardless of age, neutral memories may be strengthened by a local context that is high in valence. A trending age difference also emerged with older adults showing greater sensitivity when encoding instructions changed between trial n-1 and n. Results are discussed in light of age-related theories of cognitive and emotional processing, highlighting the need to consider the dynamic, moment-to-moment fluctuations of these systems.     

Adult age differences in temporal and item memory

Three experiments tested whether the relationship between age differences in temporal and item memory depends on the degree to which the item memory measure relies on memory for context. The authors predicted a stronger relationship of temporal memory to free recall than to recognition memory. Results showed that age differences in temporal memory could be eliminated after controlling for free recall but not recognition memory performance. Under some conditions recognition memory accounted for a significant portion of age-related variance in temporal memory. These results challenge past research that has interpreted age differences in temporal and item memory as independent and suggest that a generalized decline in context memory may underlie reduced performance in older adults on all types of memory tests.     

Trait rumination and response to negative evaluative lab-induced stress: neuroendocrine,affective, and cognitive outcomes

Theoretical models of depression posit that, under stress, elevated trait rumination predicts more pronounced or prolonged negative affective and neuroendocrine responses, and that trait rumination hampers removing irrelevant negative information from working memory. We examined several gaps regarding these models in the context of lab-induced stress. Non-depressed undergraduates completed a rumination questionnaire and either a negative-evaluative Trier Social Stress Test (n?=?55) or a non-evaluative control condition (n?=?69), followed by a modified Sternberg affective working memory task assessing the extent to which irrelevant negative information can be emptied from working memory. We measured shame, negative and positive affect, and salivary cortisol four times. Multilevel growth curve models showed rumination and stress interactively predicted cortisol reactivity; however, opposite predictions, greater rumination was associated with blunted cortisol reactivity to stress. Elevated trait rumination interacted with stress to predict augmented shame reactivity. Rumination and stress did not significantly interact to predict working memory performance, but under control conditions, rumination predicted greater difficulty updating working memory. Results support a vulnerability-stress model of trait rumination with heightened shame reactivity and cortisol dysregulation rather than hyper-reactivity in non-depressed emerging adults, but we cannot provide evidence that working memory processes are critical immediately following acute stress.     

Adult Age Differences in the Access and Deletion Functions of Inhibition

ABSTRACT

This study examined age differences in working memory using a delayed-matching-to-sample (DMTS) task. Based on the inhibitory decline hypothesis, which posits that older adults are more susceptible to interference, age differences were expected to be greater for older adults when irrelevant information was present during encoding. Two experiments tested both the access and deletion functions of inhibition. In both experiments, performance was equated for older and younger participants on a no-interference version of the DMTS task to control for age differences in encoding information into working memory. Results consistently showed equivalent effects of distraction for older and younger adults regardless of the difficulty of the perceptual discrimination of targets and distractors, the degree of processing of the distractors, or the semantic relationship between targets and distractors. These results support theories that propose age differences in encoding to explain age differences in working memory, and are inconsistent with theories that propose that older adults are more susceptible to interference than younger adults.     

Two good reasons to say ‘change!’ – ensemble representations as well as item representations impact standard measures of VWM capacity

Visual working memory (VWM) is a central bottleneck in human information processing. Its capacity is most often measured in terms of how many individual‐item representations VWM can hold (k). In the standard task employed to estimate k, an array of highly discriminable colour patches is maintained and, after a short retention interval, compared to a test display (change detection). Recent research has shown that with more complex, structured displays, change‐detection performance is, in addition to individual‐item representations, supported by ensemble representations formed as a result of spatial subgroupings. Here, by asking participants to additionally localize the change, we reveal indication for an influence of ensemble representations even in the very simple, unstructured displays of the colour‐patch change‐detection task. Critically, pure‐item models from which standard formulae of k are derived do not consider ensemble representations and, therefore, potentially overestimate k. To gauge this overestimation, we develop an item‐plus‐ensemble model of change detection and change localization. Estimates of k from this new model are about 1 item (~30%) lower than the estimates from traditional pure‐item models, even if derived from the same data sets.     

The effects of aerobic exercise on working memory in methamphetamine-dependent patients: Evidence from combined fNIRS and ERP

ObjectiveTo explore the effect of aerobic exercise on working memory according to exercise intensity in patients with methamphetamine (MA) dependence.DesignTwelve-week randomized controlled trial.MethodForty-five MA-dependent patients were divided randomly into three groups participating in 12-week moderate- and high-intensity aerobic exercise interventions and no intervention (control), respectively. Working memory performance was assessed using a 2-back task, and a combined functional near-infrared spectral imaging–event-related potential measure was used to identify spatial and temporal components of the neurofunctional underpinnings of this performance.ResultsHigh-intensity exercise significantly enhanced the discernment aspect of working memory. It also decreased N1 and P2 amplitudes, and increased neural activity in the left dorsolateral prefrontal cortex.ConclusionsThe findings of this study suggest that high-intensity aerobic exercise can enhance working memory and neural activity in MA-dependent patients, and thus that it may serve as an effective therapeutic tool for these patients.     

Aging and Working Memory Inside and Outside the Focus of Attention: Dissociations of Availability and Accessibility

ABSTRACT

Two experiments used the N-Back task to test for age differences in working memory inside and outside the focus of attention. Manipulations of the difficulty of item-context binding (Experiment 1) and of stimulus feature binding (Experiment 2) were used to create conditions that varied in their demand on working memory, with the expectation that greater demand might increase age differences in focus-switching costs and the search rate outside the focus of attention. Results showed, however, that although age differences were evident in measures of overall speed and accuracy, and the manipulations significantly affected response times and accuracy in the expected direction, the experimental manipulations had no impact on age differences. Findings instead pointed to age-related reductions in accuracy but not speed of focus-switching and search outside the focus of attention. Thus, age-related deficits appear to involve the availability of representations in working memory, but not their accessibility.     

Proactive interference in working memory is related to adult age and cognitive factors: cross-sectional and longitudinal evidence from the Betula study

ABSTRACT

In working memory (WM), successful maintenance of information is affected by interference. Older adults may be especially susceptible to the effects of interference, which may cause age-related cognitive impairments. A relative score of IC was derived from cross-sectional (n = 869) and longitudinal (n = 443) data to investigate (1) if IC is reduced in normal aging, (2) if individual differences in IC related to individual performance in other cognitive domains, and (3) if 5-year change in IC is related to change in general cognition. Older age was associated with reduced IC, but no decline in IC occurred over 5 years. Also, the ability to control interference in WM was related to performance in episodic memory, verbal fluency, and block design. We also found that IC mediates the relationship between age and cognition, suggesting that age-related cognitive decline is linked to IC. Finally, we demonstrate that change in IC was related to decline in episodic memory.     

Item-Position Effect in Raven’s Matrices: A Developmental Perspective

ABSTRACT

This study examined whether there is a developmental difference in the emergence of an item-position effect in intelligence testing. The item-position effect describes the dependency of the item’s characteristics on the positions of the items and is explained by learning. Data on fluid intelligence measured by Raven’s Standard Progressive Matrices (SPM) and data on working memory tasks were collected from both primary school age children (7–8 years old) and secondary school age adolescents (12–13 years old). The item-position effect of SPM was represented and separated from the ability component by the fixed-links model. The results indicated a clear age difference: whereas the item-position effect was observed in the adolescents, it was not found in the primary school children. In addition, separating the item-position effect detected in the adolescents from the ability component led to a larger correlation with working memory than otherwise. These results suggest that age differences in intelligence test performance may not only reflect differences in the general ability but also in the sources of the item-position effect.     

Age differences in visual working memory capacity: not based on encoding limitations

Why does visual working memory performance increase with age in childhood? One recent study ( Cowan et al., 2010b ) ruled out the possibility that the basic cause is a tendency in young children to clutter working memory with less‐relevant items (within a concurrent array, colored items presented in one of two shapes). The age differences in memory performance, however, theoretically could result from inadequate encoding of the briefly presented array items by younger children. We replicated the key part of the procedure in children 6–8 and 11–13 years old and college students (total N = 90), but with a much slower, sequential presentation of the items to ensure adequate encoding. We also required verbal responses during encoding to encourage or discourage labeling of item information. Although verbal labeling affected performance, age differences persisted across labeling conditions, further supporting the existence of a basic growth in capacity.     

Aging,imagery, and the bizarreness effect

ABSTRACT

This study examined the bizarre imagery effect in young and older adults, under incidental and intentional conditions. Intentionality was manipulated across experiments, with participants receiving an incidental free recall test in Experiment 1 and an intentional test in Experiment 2. This study also examined the relation between working memory resources and the bizarreness effect. In Experiment 1 young and older adults were presented with common and bizarre sentences; they later received an incidental recall test. There were no age differences in sensitivity to the bizarreness effect in Experiment 1 when ANOVAs were used to analyze the data. However, when the bizarreness effect was examined in terms of effect size, there was evidence that younger adults produced larger bizarreness effect sizes than younger adults. Experiment 2 further explored age differences in sensitivity to the bizarreness effect by presenting young and older adults with bizarre and common sentences under intentional learning conditions. Experiment 2 failed to yield age differences as a function of item type (bizarre vs. common). In addition, Experiment 2 failed to yield significant evidence that the bizarreness effect is modulated by working memory resources. The results of this study are most consistent with the distinctiveness account of the bizarreness effect.     

A comparison of visual working memory and episodic memory performance in younger and older adults

Working memory and episodic memory decline with age. However, as they are typically studied separately, it is largely unknown whether age-associated differences are similar. A task design was developed in which visual working memory and episodic memory performances were measured using the same stimuli, with both tasks involving context binding. A 2-back working memory task was followed by a surprise subsequent recognition memory task that assessed incidental encoding of object locations of the 2-back task. The study compared performance of younger (N=30; M_age=23.5, SD_age=2.9, range=20-29) and older adults (N=29; M_age=72.1, SD_age=6.8, range=62-90). Older adults performed worse than younger adults, without an interaction effect. In younger, but not in older adults, performance on the two tasks was related. We conclude that although age differences (Young>Older) are similar in the working memory and incidental associative memory tasks, the relationship between the two memory systems differs as a function of age group.     

Different types of working memory binding in epilepsy patients with unilateral anterior temporal lobectomy

The medial temporal lobe is an important structure for long-term memory formation, but its role in working memory is less clear. Recent studies have shown hippocampal involvement during working memory tasks requiring binding of information. It is yet unclear whether this is limited to tasks containing spatial features. The present study contrasted three binding conditions and one single-item condition in patients with unilateral anterior temporal lobectomy.A group of 43 patients with temporal lobectomy (23 left; 20 right) and 20 matched controls were examined with a working memory task assessing spatial relational binding (object–location), non-spatial relational binding (object–object), conjunctive binding (object–colour) and working memory for single items. We varied the delay period (3 or 6 s), as there is evidence showing that delay length may modulate working memory performance.The results indicate that performance was worse for patients than for controls in both relational binding conditions, whereas patients were unimpaired in conjunctive binding. Single-item memory was found to be marginally impaired, due to a deficit on long-delay trials only.In conclusion, working memory binding deficits are found in patients with unilateral anterior temporal lobectomy. The role of the medial temporal lobe in working memory is not limited to tasks containing spatial features. Rather, it seems to be involved in relational binding, but not in conjunctive binding. The medial temporal lobe gets involved when working memory capacity does not suffice, for example when relations have to be maintained or when the delay period is long.     

Explaining age differences in temporal working memory

To determine the cognitive mechanisms underlying age differences in temporal working memory (WM), the authors examined the contributions of item memory, associative memory, simple order memory, and multiple item memory, using parallel versions of the delayed-matching-to-sample task. Older adults performed more poorly than younger adults on tests of temporal memory, but there were no age differences in nonassociative item memory, regardless of the amount of information to be learned. In contrast, a combination of associative and simple order memory, both of which were reduced in older adults, completely accounted for age-related declines in temporal memory. The authors conclude that 2 mechanisms may underlie age differences in temporal WM, namely, a generalized decline in associative ability and a specific difficulty with order information.     

Temporal contiguity and ageing: The role of memory organization in cognitive decline

The temporal contiguity effect is the tendency to form associations between items presented in nearby study positions. In the present study, we explored whether temporal contiguity predicted conversion to cognitively unimpaired-declining (CUD) status from a baseline of unimpaired older adults. Data from 419 participants were drawn from the Wisconsin Registry of Alzheimer’s Prevention (WRAP) data set and analysed with binary logistic regressions. Temporal contiguity was calculated using the Rey Auditory Verbal Learning Test. Other predictors included age, years of education, sex, APOE-ε4 status, and other measures of memory recall. Lower temporal contiguity predicted conversion to CUD after accounting for covariates. These findings support the hypothesis that temporal organization in memory is related to cognitive decline and suggest that temporal contiguity may be used for studies of early detection.     

A test of the CaR-FA-X mechanisms and depression in adolescents

ABSTRACT

People who have depression have difficulty recalling specific autobiographical information (Sumner, (2011) The mechanisms underlying overgeneral autobiographical memory: An evaluative review of evidence for the Ca R-FA-X model. Clinical Psychology Review, 3231(1), 34–48). This is called overgeneral autobiographical memory (OGM) and is associated with the development and persistence of depression. Williams, Barnhofer, Crane, Hermans, Raes, Watkins, & Dalgleish (2007 Autobiographical memory specificity and emotional disorder. Psychological Bulletin, 133(1), 122–148) proposed that OGM is maintained by three mechanisms: capture and rumination (CaR), functional avoidance (FA), and impaired executive control (X), and integrated these into the CaR-FA-X model. The aim of this study was to assess OGM and test the CaR-FA-X model in adolescents with low mood. We recruited 29 young people aged 12–17 with elevated symptoms of depression and 29 with minimal symptoms of depression, matched for gender and age. After controlling for IQ, adolescents with elevated depression retrieved fewer specific memories, ruminated more, and had poorer working memory and verbal fluency than adolescents with minimal depression. The groups did not differ on measures of inhibition or functional avoidance. The CaR-FA-X model was therefore partially supported. These results confirm that there is a relationship between low mood and OGM in young people and that OGM may arise as consequence of impaired working memory and verbal fluency and cognitive interference due to rumination.