Differential age effects for implicit and explicit conceptual associative memory

Deficits in memory metacognitive efficiency in late adulthood are related to distinct brain profile

The tendency of falsely remembering events that did not happen in the past increases with age. This is particularly evident in cases in which features presented at study are re-presented at test in a recombined constellation (termed rearranged pairs). Interestingly, older adults also express high confidence in such false memories, a tendency that may indicate reduced metacognitive efficiency. Within an existing cohort study, we aimed at investigating age-related differences in memory metacognitive efficiency (as measured by meta d' ratio) in a sample of 1522 older adults and 397 young adults. The analysis showed an age-related deficit in metacognition which was more pronounced for rearranged pairs than for new pairs. We then explored associations between cortical thickness and memory metacognitive efficiency for rearranged pairs in a subsample of 231 older adults. By using partial least square analysis, we found that a multivariate profile composed by ventromedial prefrontal cortex, insula, and parahippocampal cortex was uniquely associated with between-person differences in memory metacognitive efficiency. These results suggest that the impairment in memory metacognitive efficiency for false alarms is a distinct age-related deficit, above and beyond a general age-related decline in memory discrimination, and that it is associated with brain regions involved in metacognitive processes.

Smartphone use as an efficient tool to improve anomia in primary progressive aphasia

Cognitive interventions are helpful in the non-pharmacological management of Primary progressive aphasia (PPA) and other neurodegenerative disorders of cognition, by helping patients to compensate for their cognitive deficits and improve their functional independence. In this study, we examined the effectiveness of cognitive rehabilitation based on the use of mobile device technology in PPA. The aim of this research study was to determine if BL, a patient with semantic variant PPA (svPPA) and severe anomia, was able to learn using specific smartphone functions and an application to reduce her word finding difficulties. She was trained during the intervention sessions on a list of target pictures to measure changes in picture naming performance. Errorless learning was applied during learning. BL quickly learned to use smartphone functions and the application over the course of the intervention. She significantly improved her anomia for trained pictures, and to a lesser extent for untrained semantically related pictures. Picture naming performance was maintained six months after the intervention, and she continued to use her smartphone regularly to communicate with family members and friends. This study confirms that smartphone use can be learned in PPA, which can help reduce the symptoms of anomia and improve communication skills.

Some young adults hyper-bind too: Attentional control relates to individual differences in hyper-binding

Hyper-binding - the erroneous encoding of target and distractor information into associative pairs in memory - has been described as a unique age effect caused by declines in attentional control. Previous work has found that, on average, young adults do not hyper-bind. However, if hyper-binding is caused by reduced attentional control, then young adults with poor attention regulation should also show evidence of hyper-binding. We tested this question with an individual differences approach, using a battery of attentional control tasks and relating this to individual differences in hyper-binding. Participants (N = 121) completed an implicit associative memory test measuring memory for both target-distractor (i.e., hyper-binding) and target-target pairs, followed by a series of tasks measuring attentional control. Our results show that on average, young adults do not hyper-bind, but as predicted, those with poor attentional control show a larger hyper-binding effect than those with good attentional control. Exploratory analyses also suggest that individual differences in attentional control relate to susceptibility to interference at retrieval. These results support the hypothesis that hyper-binding in older adults is due to age-related declines in attentional control, and demonstrate that hyper-binding may be an issue for any individual with poor attentional control, regardless of age.

The Interactive Role of Sleep and Circadian Rhythms in Episodic Memory in Older Adults

Adequate sleep is essential for healthy physical, emotional, and cognitive functioning, including memory. However, sleep ability worsens with increasing age. Older adults on average have shorter sleep durations and more disrupted sleep compared with younger adults. Age-related sleep changes are thought to contribute to age-related deficits in episodic memory. Nonetheless, the nature of the relationship between sleep and episodic memory deficits in older adults is still unclear. Further complicating this relationship are age-related changes in circadian rhythms such as the shift in chronotype toward morningness and decreased circadian stability, which may influence memory abilities as well. Most sleep and cognitive aging studies do not account for circadian factors, making it unclear whether age-related and sleep-related episodic memory deficits are partly driven by interactions with circadian rhythms. This review will focus on age-related changes in sleep and circadian rhythms and evidence that these factors interact to affect episodic memory, specifically encoding and retrieval. Open questions, methodological considerations, and clinical implications for diagnosis and monitoring of age-related memory impairments are discussed.

Study-test congruence of response levels in item stimulus-response priming

We investigated stimulus-response (S-R) memory links during object priming using a binary associative size judgement paradigm. At study, participants decided which of two objects was bigger in real life and, at test, made the same or the reverse judgement. We examined the effects of response congruence on item S-R priming in the associative paradigm. In Experiment 1, a task reversal manipulation had minimal impact on RT priming when classifications were congruent for both recombined objects between study and test. Experiment 2 found that RT priming was more disrupted by classification incongruence of the selected than of the nonselected item alone, with incongruence of the nonselected object having no effect on RTs. Experiment 3, however, found that classification incongruence of both items eliminated RT priming, indicating that a significant effect of classification incongruence for the nonselected item is only evident if both items are classification-incongruent. Finally, across all experiments, we found that accuracy was more sensitive than RTs to decision/action incongruence. We interpret these findings in light of a two-stream account of S-R priming, and suggest a few extensions to account for interactions between S-R links of recombined items.

Encoding and retrieval eye movements mediate age differences in pattern completion

Older adults often mistake new information as 'old', yet the mechanisms underlying this response bias remain unclear. Typically, false alarms by older adults are thought to reflect pattern completion - the retrieval of a previously encoded stimulus in response to partial input. However, other work suggests that age-related retrieval errors can be accounted for by deficient encoding processes. In the present study, we used eye movement monitoring to quantify age-related changes in behavioral pattern completion as a function of eye movements during both encoding and partially cued retrieval. Consistent with an age-related encoding deficit, older adults executed more gaze fixations and more similar eye movements across repeated image presentations than younger adults, and such effects were predictive of subsequent recognition memory. Analysis of eye movements at retrieval further indicated that in response to partial lure cues, older adults reactivated the similar studied image, indexed by the similarity between encoding and retrieval gaze patterns, and did so more than younger adults. Critically, reactivation of encoded image content via eye movements was associated with lure false alarms in older adults, providing direct evidence for a pattern completion bias. Together, these findings suggest that age-related changes in both encoding and retrieval processes, indexed by eye movements, underlie older adults' increased vulnerability to memory errors.

Neural Correlates of Enhanced Memory for Meaningful Associations with Age

Evidence suggests that age differences in associative memory are attenuated for associations that are consistent with prior knowledge. Such knowledge structures have traditionally been associated with the default network (DN), which also shows reduced modulation with age. In the present study, we investigated whether DN activity and connectivity patterns could account for this age-related effect. Younger and older adults underwent functional magnetic resonance imaging as they learned realistic and unrealistic prices of common grocery items. Both groups showed greater activity in the DN during the encoding of realistic, relative to unrealistic, prices. Moreover, DN activity at encoding and retrieval and its connectivity with an attention control network at encoding were associated with enhanced memory for realistic prices. Finally, older adults showed overactivation of control regions during retrieval of realistic prices relative to younger adults. Our findings suggest that DN activity and connectivity patterns (traditionally viewed as indicators of cognitive failure with age), and additional recruitment of control regions, might underlie older adults' enhanced memory for meaningful associations.

Implicit associative memory remains intact with age and extends to target-distractor pairs

In this study, we use a novel, implicit memory paradigm to test forhyper-binding, or older adults' tendency to form non-target associations. Participants viewed pictures of objects superimposed with text and made speeded categorization judgments about the objects across three blocks varying in binding demand. During the no- and some-binding blocks, participants decided if the pictured object alone could fit inside a drawer while ignoring superimposed non-words and words, respectively. During the full-binding block, participants decided if both items could fit inside a drawer together. At test, participants viewed intact and rearranged pairs from encoding and decided if both items could fit in a drawer together. Across two experiments, older adults responded faster to intact than rearranged pairs from both the some- and full-binding blocks, while young adults showed no difference in RTs. These findings suggest that implicit associative memory is preserved with age and extends to non-target information.

Priming older adults and people with mild to moderate Alzheimer's disease problem-solving with false memories

In two experiments we investigated whether older adult controls (OACs) and people with mild and moderate Alzheimer's disease (AD) benefit from false memory priming effects in subsequent problem-solving tasks. In addition, and unlike in previous false memory priming studies with older adults, we examined latency measures in the recognition phase. In Experiment 1 participants were asked to solve compound remote associate task (CRAT) problems, half of which had been preceded by the presentation of Deese/Roediger-McDermott (DRM) lists whose critical lures (CLs) were also the solutions to those problems. In Experiment 2, we used a similar paradigm but investigated whether CLs could prime solutions to subsequent analogical reasoning problems. In this latter experiment, we also examined whether these priming effects were stronger when the activation of the CL term occurred during the memory task (was presented as part of the list; i.e., true memories) or when these items were not presented but arose during encoding due to spreading activation (i.e., false memories). We found that all three groups' performance on these tasks was facilitated only by false memories spontaneously generated from the prior presentation of DRM lists. That is, performance on CRATs and analogical reasoning tasks was better (greater accuracy and faster speed) when those problems were preceded by DRM lists whose CLs also served as the solution to those problems. These findings are consistent with previous results from studies with children, young adults, and older adults and extends them to people with more moderate AD.

Age-Related Differences in the Impact of Prior Knowledge on Recognition Performance: A Face Recognition Study

Background/Study context: The dual-process hypothesis of memory and aging (DPHMA) postulates a decline of recollection with no decline in recognition. While the age-related recollection deficit is well-documented, any age-changes in the familiarity process remain unclear. Some studies have shown that familiar and meaningful material can enhance the recognition performance of older adults. The goal of the present study was to explore the impact of familiar material on age-related recognition-memory decline, using a dual-process approach.

METHODS

One hundred participants (50 young adults and 50 older adults) performed two recognition tasks using an unfamiliar and a famous face recognition task. A receiver operating characteristic (ROC) analysis was used to examine the memory processes underlying recognition memory.

RESULTS

The older adults showed lower performance on recognition accuracy and false alarms rate, only in the unfamiliar-face recognition task. A DPHMA-like pattern on unfamiliar-face recognition task was obtained. Prior knowledge in the famous-face recognition task improved recollection for older adults and no age-related deficit was found.

CONCLUSION

The present study suggests that episodic memory deficits in healthy aging are primarily driven by a recollection deficit while familiarity is relatively well spared. However, this age-related recollection deficit could be alleviated using knowledge-based material.

Aging and recognition memory: A meta-analysis

Recognizing a stimulus as previously encountered is a crucial everyday life skill and a critical task motivating theoretical development in models of human memory. Although there are clear age-related memory deficits in tasks requiring recall or memory for context, the existence and nature of age differences in recognition memory remain unclear. The nature of any such deficits is critical to understanding the effects of age on memory because recognition tasks allow fewer strategic backdoors to supporting memory than do tasks of recall. Consequently, recognition may provide the purest measure of age-related memory deficit of all standard memory tasks. We conducted a meta-analysis of 232 prior experiments on age differences in recognition memory. As an organizing framework, we used signal-detection theory (Green & Swets, 1966; Macmillan & Creelman, 2005) to characterize recognition memory in terms of both discrimination between studied items and unstudied lures (d') and response bias or criterion (c). Relative to young adults, older adults showed reduced discrimination accuracy and a more liberal response criterion (i.e., greater tendency to term items new). Both of these effects were influenced by multiple, differing variables, with larger age deficits when studied material must be discriminated from familiar or related material, but smaller when studying semantically rich materials. These results support a view in which neither the self-initiation of mnemonic processes nor the deployment of strategic processes is the only source of age-related memory deficits, and they add to our understanding of the mechanisms underlying those changes. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Implicit motivation improves executive functions of older adults

It is widely accepted that while controlled processes (e.g., working memory and executive functions) decline with age, implicit (automatic) processes are not affected by age. In this paper we challenge this view by arguing that high-level automatic processes (e.g., recruiting motivation) decline with age, and that this decline plays an unappreciated role in cognitive aging. Specifically, we hypothesized that due to their decline, automatic motivational processes are less likely to be spontaneously activated in old age; thus, implicit external activation of them should have stronger effects on older (vs. younger) adults. In two experiments we used different methods of implicitly activating motivation, and measured executive functions of younger and older adults using the Wisconsin Card Sorting Test. In both experiments, implicit modulation of motivation resulted in improved executive functioning for older adults. The framework we propose is general and offers a new look at various aspects of cognitive aging.

Visual Acuity does not Moderate Effect Sizes of Higher-Level Cognitive Tasks

BACKGROUND/STUDY CONTEXT

Declining visual capacities in older adults have been posited as a driving force behind adult age differences in higher-order cognitive functions (e.g., the "common cause" hypothesis of Lindenberger & Baltes, 1994, Psychology and Aging, 9, 339-355). McGowan, Patterson, and Jordan (2013, Experimental Aging Research, 39, 70-79) also found that a surprisingly large number of published cognitive aging studies failed to include adequate measures of visual acuity. However, a recent meta-analysis of three studies (La Fleur and Salthouse, 2014, Psychonomic Bulletin & Review, 21, 1202-1208) failed to find evidence that visual acuity moderated or mediated age differences in higher-level cognitive processes. In order to provide a more extensive test of whether visual acuity moderates age differences in higher-level cognitive processes, we conducted a more extensive meta-analysis of topic.

METHODS

Using results from 456 studies, we calculated effect sizes for the main effect of age across four cognitive domains (attention, executive function, memory, and perception/language) separately for five levels of visual acuity criteria (no criteria, undisclosed criteria, self-reported acuity, 20/80-20/31, and 20/30 or better).

RESULTS

As expected, age had a significant effect on each cognitive domain. However, these age effects did not further differ as a function of visual acuity criteria.

CONCLUSION

The current meta-analytic, cross-sectional results suggest that visual acuity is not significantly related to age group differences in higher-level cognitive performance-thereby replicating La Fleur and Salthouse (2014). Further efforts are needed to determine whether other measures of visual functioning (e.g., contrast sensitivity, luminance) affect age differences in cognitive functioning.

Multiple determinants of lifespan memory differences

Memory problems are among the most common complaints as people grow older. Using structural equation modeling of commensurate scores of anterograde memory from a large (N = 315), population-derived sample (www.cam-can.org), we provide evidence for three memory factors that are supported by distinct brain regions and show differential sensitivity to age. Associative memory and item memory are dramatically affected by age, even after adjusting for education level and fluid intelligence, whereas visual priming is not. Associative memory and item memory are differentially affected by emotional valence, and the age-related decline in associative memory is faster for negative than for positive or neutral stimuli. Gray-matter volume in the hippocampus, parahippocampus and fusiform cortex, and a white-matter index for the fornix, uncinate fasciculus and inferior longitudinal fasciculus, show differential contributions to the three memory factors. Together, these data demonstrate the extent to which differential ageing of the brain leads to differential patterns of memory loss.

Associative and Implicit Memory Performance as a Function of Cognitive Reserve in Elderly Adults with and without Mild Cognitive Impairment

This study aims to analyze implicit and explicit memory performance as a function of cognitive reserve (CR) in a healthy control group (N = 39) and a mild cognitive impairment (MCI) group (N = 37). Both groups were subdivided into high and low cognitive reserve, and were asked to complete an explicit and implicit associative recognition tasks. The results showed that the control group was able to learn both tasks (η2 = .19, p < .0001), and the high CR group fared better (η2 = .06, p < .05). The MCI sample, conversely, was unable to learn the implicit relationship, and showed very little learning on the explicit association task. Participants diagnosed with MCI showed little plasticity in learning associations regardless of CR (η2 = .12, p < .01).

Preserved memory-based orienting of attention with impaired explicit memory in healthy ageing

It is increasingly recognised that spatial contextual long-term memory (LTM) prepares neural activity for guiding visuo-spatial attention in a proactive manner. In the current study, we investigated whether the decline in explicit memory observed in healthy ageing would compromise this mechanism. We compared the behavioural performance of younger and older participants on learning new contextual memories, on orienting visual attention based on these learnt contextual associations, and on explicit recall of contextual memories. We found a striking dissociation between older versus younger participants in the relationship between the ability to retrieve contextual memories versus the ability to use these to guide attention to enhance performance on a target-detection task. Older participants showed significant deficits in the explicit retrieval task, but their behavioural benefits from memory-based orienting of attention were equivalent to those in young participants. Furthermore, memory-based orienting correlated significantly with explicit contextual LTM in younger adults but not in older adults. These results suggest that explicit memory deficits in ageing might not compromise initial perception and encoding of events. Importantly, the results also shed light on the mechanisms of memory-guided attention, suggesting that explicit contextual memories are not necessary.

Associative memory in aging: the effect of unitization on source memory

In normal aging, memory for associations declines more than memory for individual items. Unitization is an encoding process defined by creation of a new single entity to represent a new arbitrary association. The current study tested the hypothesis that age-related differences in associative memory can be reduced by encoding instructions that promote unitization. In two experiments, groups of 20 young and 20 older participants learned new associations between a word and a background color under two conditions. In the item detail condition, they had to imagine that the item is the same color as the background-an instruction promoting unitization of the associations. In the context detail condition, which did not promote unitization, they had to imagine that the item interacted with another colored object. At test, they had to retrieve the color that was associated with each word (source memory). In both experiments, the results showed an age-related decrement in source memory performance in the context detail but not in the item detail condition. Moreover, Experiment 2 examined receiver operating characteristics in older participants and indicated that familiarity contributed more to source memory performance in the item detail than in the context detail condition. These findings suggest that unitization of new associations can overcome the associative memory deficit observed in aging, at least for item-color associations.

Effect of repetition lag on priming of unfamiliar visual objects in young and older adults

Across three experiments, we examined the effect of repetition lag on priming of unfamiliar visual objects in healthy young and older adults. Multiple levels of lag were examined, ranging from short (one to four intervening stimuli) to long (50 + intervening stimuli). In each experiment, subjects viewed a series of new and repeated line drawings of objects and decided whether they depicted structurally possible or impossible figures. Experiment 1 and 2 found similar levels of priming in young and older adults at short and medium lags. At the longer repetition lags (∼20 + intervening stimuli), older adults showed less overall priming, as measured by reaction time (RT) facilitation, than young adults. This indicates that older adults can rapidly encode unfamiliar three-dimensional objects to support priming at shorter lags; however, they cannot maintain these representations over longer intervals. In addition to repetition lag, we also explored the relationship between priming and cognitive reserve, as measured by education and verbal intelligence. In the older adults, higher levels of cognitive reserve were associated with greater RT priming, suggesting that cognitive reserve may mediate the relationship between aging and priming.

Reduced specificity of hippocampal and posterior ventrolateral prefrontal activity during relational retrieval in normal aging

Neuroimaging studies of episodic memory in young adults demonstrate greater functional neural activity in ventrolateral pFC and hippocampus during retrieval of relational information as compared with item information. We tested the hypothesis that healthy older adults--individuals who exhibit behavioral declines in relational memory--would show reduced specificity of ventrolateral prefrontal and hippocampal regions during relational retrieval. At study, participants viewed two nouns and were instructed to covertly generate a sentence that related the words. At retrieval, fMRIs were acquired during item and relational memory tasks. In the relational task, participants indicated whether the two words were previously seen together. In the item task, participants indicated whether both items of a pair were previously seen. In young adults, left posterior ventrolateral pFC and bilateral hippocampal activity was modulated by the extent to which the retrieval task elicited relational processing. In older adults, activity in these regions was equivalent for item and relational memory conditions, suggesting a reduction in ventrolateral pFC and hippocampal specificity with normal aging.

The status of rapid response learning in aging

Strong evidence exists for an age-related impairment in associative processing under intentional encoding and retrieval conditions, but the status of incidental associative processing has been less clear. In 2 experiments, we examined the effects of age on rapid response learning-the incidentally learned stimulus-response association that results in a reduction in priming when a learned response becomes inappropriate for a new task. Specifically, we tested whether priming was equivalently sensitive in both age groups to reversal of the task-specific decision cue. Experiment 1 showed that cue inversion reduced priming in both age groups with a speeded inside/outside classification task, and in Experiment 2, cue inversion eliminated priming on an associative version of this task. Thus, the ability to encode an association between a stimulus and its initial task-specific response appears to be preserved in aging. These findings provide an important example of a form of associative processing that is unimpaired in older adults.