Conceptual processing of distractors by older but not younger adults

The assessment of executive function abilities in healthy and neurodegenerative aging-A selective literature review

Numerous studies have examined executive function (EF) abilities in cognitively healthy older adults and those living with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Currently, there are no standard accepted protocols for testing specific EFs; thus, researchers have used their preferred tool, which leads to variability in assessments of decline in a particular ability across studies. Therefore, there is a need for guidance as to the most sensitive tests for assessing EF decline. A search of the most current literature published between 2000 and 2022 on EF studies assessing cognitively healthy older adults and individuals living with MCI and AD was conducted using PubMed/Medline, PsycINFO, Embase, Web of Science, and Google Scholar. Emphasis was placed on the EF's dual-tasking, inhibition, shifting or switching, and working memory updating. Many tasks and their outcomes were reviewed. Of particular importance was the difference in outcomes for tasks applied to the same group of participants. These various EF assessment tools demonstrate differences in effectively identifying decline in EF ability due to the aging process and neurodegenerative conditions, such as MCI and AD. This review identifies various factors to consider in using particular EF tasks in particular populations, including task demand and stimuli factors, and also when comparing differing results across studies.

Are older adults susceptible to visual distraction when targets and distractors are spatially separated?

Older adults show preserved memory for previously distracting information due to reduced inhibitory control. In some previous studies, targets and distractors overlap both temporally and spatially. We investigated whether age differences in attentional orienting and disengagement affect recognition memory when targets and distractors are spatially separated at encoding. In Experiments 1 and 2, eye movements were recorded while participants completed an incidental encoding task under covert (i.e., restricted viewing) and overt (i.e., free-viewing) conditions, respectively. The encoding task consisted of pairs of target and distractor item-color stimuli presented in separate visual hemifields. Prior to stimulus onset, a central cue indicated the location of the upcoming target. Participants were subsequently tested on their recognition of the items, their location, and the associated color. In Experiment 3, targets were validly cued on 75% of the encoding trials; on invalid trials, participants had to disengage their attention from the distractor and reorient to the target. Associative memory for colors was reduced among older adults across all experiments, though their location memory was only reduced in Experiment 1. In Experiment 2, older and younger adults directed a similar proportion of fixations toward targets and distractors. Explicit recognition of distractors did not differ between age groups in any of the experiments. However, older adults were slower to correctly recognize distractors than false alarm to novel items in Experiment 2, suggesting some implicit memory for distraction. Together, these results demonstrate that older adults may only be vulnerable to encoding visual distraction when viewing behavior is unconstrained.

Americans weigh an attended emotion more than Koreans in overall mood judgments

Face ensemble coding is the perceptual ability to create a quick and overall impression of a group of faces, triggering social and behavioral motivations towards other people (approaching friendly people or avoiding an angry mob). Cultural differences in this ability have been reported, such that Easterners are better at face ensemble coding than Westerners are. The underlying mechanism has been attributed to differences in processing styles, with Easterners allocating attention globally, and Westerners focusing on local parts. However, the remaining question is how such default attention mode is influenced by salient information during ensemble perception. We created visual displays that resembled a real-world social setting in which one individual in a crowd of different faces drew the viewer's attention while the viewer judged the overall emotion of the crowd. In each trial, one face in the crowd was highlighted by a salient cue, capturing spatial attention before the participants viewed the entire group. American participants' judgment of group emotion more strongly weighed the attended individual face than Korean participants, suggesting a greater influence of local information on global perception. Our results showed that different attentional modes between cultural groups modulate social-emotional processing underlying people's perceptions and attributions.

Memory, aging and the brain: Old findings and current issues

In this article I reprise some selected findings and issues from my previous behavioural work on age-related differences in memory, and relate them to current work on the neural correlates of encoding, retrieval and representation. In particular, I describe the case study of a woman who had persistent experiences of erroneous recollection. I also describe the results of a study showing a double dissociation of implicit and explicit memory in younger and older adults. Finally, I assess recent work on loss of specificity in older adults' encoding and retrieval processes of episodic events. In all cases I attempt to relate these older findings to current ideas and empirical results in the area of memory, aging, and the brain.

Implicit processes enhance cognitive abilities in mild cognitive impairment

Previous work has shown that older adults with typical age-related memory changes (i.e., without cognitive impairment) pick up irrelevant information implicitly, and unknowingly use that information when it becomes relevant to a later task. Here, we address the possibility that implicit processes play a similarly beneficial role in the cognitive abilities of individuals with amnestic mild cognitive impairment (aMCI). Twenty-two individuals with aMCI and 22 matched controls participated in a picture judgment task while instructed to ignore distractions in the form of word/non-word letter strings. Memory for the distracting words was later tested with a word-fragment completion task. Both groups showed a priming effect, that is, they were significantly more likely to solve fragments of previously presented than non-presented words. However, the aMCI group had significantly higher scores than the older adults without cognitive impairment, t(42) = 2.16, p < .05, Cohen's d = 0.67. Our findings suggest that individuals with aMCI can enhance their performance on an explicit cognitive task, in this case, word-fragment completion, if previously exposed to the relevant information implicitly, opening up possible interventions aimed at this population.

The benefits of immature cognitive control: How distributed attention guards against learning traps

Cognitive control allows one to focus one's attention efficiently on relevant information while filtering out irrelevant information. This ability provides a means of rapid and effective learning, but using this control also brings risks. Importantly, useful information may be ignored and missed, and learners may fall into "learning traps" (e.g., learned inattention) wherein they fail to realize that what they ignore carries important information. Previous research has shown that adults may be more prone to such traps than young children, but the mechanisms underlying this difference are unclear. The current study used eye tracking to examine the role of attentional control during learning in succumbing to these learning traps. The participants, 4-year-old children and adults, completed a category learning task in which an unannounced switch occurred wherein the feature dimensions most relevant to correct categorization became irrelevant and formerly irrelevant dimensions became relevant. After the switch, adults were more likely than children to ignore the new highly relevant dimension and settle on a suboptimal categorization strategy. Furthermore, eye-tracking analyses reveal that greater attentional selectivity during learning (i.e., optimizing attention to focus only on the most relevant sources of information) predicted this tendency to miss important information later. Children's immature cognitive control, leading to broadly distributed attention, appears to protect children from this trap-although at the cost of less efficient and slower learning. These results demonstrate the double-edged sword of cognitive control and suggest that immature control may serve an adaptive function early in development.

Pay attention and you might miss it: Greater learning during attentional lapses

Attentional lapses have been found to impair everything from basic perception to learning and memory. Yet, despite the well-documented costs of lapses on cognition, recent work suggests that lapses might unexpectedly confer some benefits. One potential benefit is that lapses broaden our learning to integrate seemingly irrelevant content that could later prove useful-a benefit that prior research focusing only on goal-relevant memory would miss. Here, we measure how fluctuations in sustained attention influence the learning of seemingly goal-irrelevant content that competes for attention with target content. Participants completed a correlated flanker task in which they categorized central targets (letters or numbers) while ignoring peripheral flanking symbols that shared hidden probabilistic relationships with the targets. We found that across participants, higher rates of attentional lapses correlated with greater learning of the target-flanker relationships. Moreover, within participants, learning was more evident during attentional lapses. These findings address long-standing theoretical debates and reveal a benefit of attentional lapses: they expand the scope of learning and decisions beyond the strictly relevant.

Narrative thinking lingers in spontaneous thought

Some experiences linger in mind, spontaneously returning to our thoughts for minutes after their conclusion. Other experiences fall out of mind immediately. It remains unclear why. We hypothesize that an input is more likely to persist in our thoughts when it has been deeply processed: when we have extracted its situational meaning rather than its physical properties or low-level semantics. Here, participants read sequences of words with different levels of coherence (word-, sentence-, or narrative-level). We probe participants’ spontaneous thoughts via free word association, before and after reading. By measuring lingering subjectively (via self-report) and objectively (via changes in free association content), we find that information lingers when it is coherent at the narrative level. Furthermore, and an individual’s feeling of transportation into reading material predicts lingering better than the material’s objective coherence. Thus, our thoughts in the present moment echo prior experiences that have been incorporated into deeper, narrative forms of thinking.

Some experiences linger in our minds, while others quickly fade. Here, the authors show that the extent to which our recent experiences linger into subsequent thought increases as a function of processing depth.

Ageing and selective inhibition of irrelevant information in an attention-demanding rapid serial visual presentation task

Attention involves both an ability to selectively focus on relevant information and simultaneously ignore irrelevant information (i.e. inhibitory control). Many factors impact inhibitory control such as individual differences, relative timing of stimuli presentation, distractor characteristics, and participant age. Previous research with young adults responding to an attention-demanding rapid serial visual presentations of pictures superimposed with task-irrelevant words evaluated the extent to which unattended information may be subject to inhibitory control. Surprise recognition tests following the rapid serial visual presentation task showed that recognition for unattended words presented with non-targets (i.e. non-aligned or ‘NA’ words) during the rapid serial visual presentation task were recognised at chance levels. However, when the unattended words were infrequently paired with the attended picture targets (i.e. target-aligned or ‘TA’ words), recognition rates were significantly below chance and significantly lower compared to NA words, suggesting selective inhibitory control for the previously unattended TA words. The current study adapted this paradigm to compare healthy younger and older adults’ ability to engage in inhibitory control. In line with previous research, younger adults demonstrated selective inhibition with recognition rates for TA words significantly lower than NA words and chance, while NA words were recognised at chance levels. However, older adults showed no difference in recognition rates between word types (TA versus NA). Rather all items were recognised at rates significantly below chance suggesting inhibited recognition for all unattended words, regardless of when they were presented during the primary task. Finally, older adults recognised significantly fewer NA words compared to young adults. These findings suggest that older adults may experience a decline in their ability to selectively inhibit the processing of irrelevant information, while maintaining the capacity to exercise global inhibition over unattended lexical information.

Examining the effects of time of day and sleep on generalization

Extracting shared structure across our experiences allows us to generalize our knowledge to novel contexts. How do different brain states influence this ability to generalize? Using a novel category learning paradigm, we assess the effect of both sleep and time of day on generalization that depends on the flexible integration of recent information. Counter to our expectations, we found no evidence that this form of generalization is better after a night of sleep relative to a day awake. Instead, we observed an effect of time of day, with better generalization in the morning than the evening. This effect also manifested as increased false memory for generalized information. In a nap experiment, we found that generalization did not benefit from having slept recently, suggesting a role for time of day apart from sleep. In follow-up experiments, we were unable to replicate the time of day effect for reasons that may relate to changes in category structure and task engagement. Despite this lack of consistency, we found a morning benefit for generalization when analyzing all the data from experiments with matched protocols (n = 136). We suggest that a state of lowered inhibition in the morning may facilitate spreading activation between otherwise separate memories, promoting this form of generalization.

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.

Age differences in vulnerability to distraction under arousal

Aging affects brain circuitry involved in both inhibition and arousal. In this study, we tested whether older adults are more or less prone to distraction from emotionally arousing events than young adults. To do so, we examined how arousing taboo distractor words affected concurrent 1-back task performance and subsequent memory for distractors. Our second goal was to examine how the arousal level of 1 item can modulate processing of preceding neutral distractors (taboo-minus-1 distractors). During the task, participants first made 1-back judgments about target pictures that were superimposed with to-be-ignored neutral or taboo distractors. Relative to young adults, older adults were more distracted by taboo than neutral words on the 1-back task and remembered more of the taboo distractors on a later incidental recognition task. Furthermore, young adults showed better suppression of taboo-minus-1 distractors than neutral distractors, whereas in older adults, arousal did not facilitate suppression of taboo-minus-1 distractors. This effect appeared to require attentional control as adding an unrelated attentional load during the 1-back task eliminated the beneficial effect of arousal for young adults' suppression of taboo-minus-1 distractors. Finally, when top-down attentional guidance was provided by increasing the goal relevance of target pictures, both groups showed enhanced suppression of taboo-minus-1 distractors versus other neutral distractors. Together, these findings imply that the effect of arousal on distractibility in aging may arise from an interaction between top-down and bottom-up processes. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

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

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

The role of executive control in post-stroke aphasia treatment

Executive control (EC) ability is increasingly emerging as an important predictor of post-stroke aphasia recovery. This study examined whether EC predicted immediate treatment gains, treatment maintenance and generalization after naming therapy in ten adults with mild to severe chronic post-stroke aphasia. Performance on multiple EC tasks allowed for the creation of composite scores for common EC, and the EC processes of shifting, inhibition and working memory (WM) updating. Participants were treated three times a week for five weeks with a phonological naming therapy; difference scores in naming accuracy of treated and untreated words (assessed pre, post, four- and eight-weeks after therapy) served as the primary outcome measures. Results from simple and multiple linear regressions indicate that individuals with better shifting and WM updating abilities demonstrated better maintenance of treated words at four-week follow-up, and those with better common EC demonstrated better maintenance of treated words at both four- and eight-week follow-ups. Better shifting ability also predicted better generalization to untreated words post-therapy. Measures of EC were not indicative of improvements on treated words immediately post-treatment, nor of generalization to untreated words at follow-up. Findings suggest that immediate treatment gains, maintenance and generalization may be supported by different underlying mechanisms.

The Shifting Architecture of Cognition and Brain Function in Older Adulthood

Cognitive aging is often described in the context of loss or decline. Emerging research suggests that the story is more complex, with older adults showing both losses and gains in cognitive ability. With increasing age, declines in controlled, or fluid, cognition occur in the context of gains in crystallized knowledge of oneself and the world. This inversion in cognitive capacities, from greater reliance on fluid abilities in young adulthood to increasingly crystallized or semanticized cognition in older adulthood, has profound implications for cognitive and real-world functioning in later life. The shift in cognitive architecture parallels changes in the functional network architecture of the brain. Observations of greater functional connectivity between lateral prefrontal brain regions, implicated in cognitive control, and the default network, implicated in memory and semantic processing, led us to propose the default-executive coupling hypothesis of aging. In this review we provide evidence that these changes in the functional architecture of the brain serve as a neural mechanism underlying the shifting cognitive architecture from younger to older adulthood. We incorporate findings spanning cognitive aging and cognitive neuroscience to present an integrative model of cognitive and brain aging, describing its antecedents, determinants, and implications for real-world functioning.

States of focused attention and sequential action: A comparison of single session meditation and computerised attention task influences on top-down control during sequence learning

Motor sequence learning is considered the result of the outflow of information following cognitive control processes that are shared by other goal-directed behaviours. Emerging evidence suggests that focused-attention meditation (FAM) establishes states of enhanced cognitive control, that then exert top-down control biases in subsequent unrelated tasks. With respect to sequence learning, a single-session of FAM has been shown to entrain stimulus-dependent forms of sequential behaviour in meditation naïve individuals. In the present experiment, we compared single-session effects of FAM and a computerised attention task (CAT) to test if FAM-induced enhanced top-down control is generally comparable to cognitive tasks that require focused attention. We also investigated if effort, arousal or pleasure associated with FAM, or CAT explained the influence of these tasks on sequence learning. Relative to a rest-only control condition, both FAM and CAT resulted in shorter reaction time (RT) in a serial reaction time task (SRTT), and this enhanced RT performance was associated with higher reliance on stimulus-based planning as opposed to sequence representation formation. However, following FAM, a greater rate of improvement in RT performance was observed in comparison to both CAT and control conditions. Neither effort, arousal nor pleasure associated with FAM or CAT explained SRTT performance. These findings were interpreted to suggest that the effect of FAM states on increased top-down control during sequence learning is based on the focused attention control feature of this meditation. FAM states might be associated with enhanced cognitive control to promote the development of more efficient stimulus-response processing in comparison to states induced by other attentional tasks.

When comprehension elicits incomprehension: Deterioration of semantic categorisation in the absence of stimulus repetition

Repetition improves retrieval from memory; however, under some circumstances, it can also impair performance. Separate literatures have investigated this phenomenon, including studies showing subjective loss of meaning following ‘semantic satiation’, slowed naming and categorisation when semantically related items are repeated and semantic ‘access deficits’ in aphasia. Such effects have been variously explained in terms of habituation of repeatedly accessed representations, increased interference from strongly activated competitors and long-term weight changes reflecting the suppression of non-targets on earlier trials (i.e., retrieval-induced forgetting). While studies of semantic satiation involve massed repetition of individual items, competition and weight changes at the conceptual level should elicit declining comprehension for non-repeated items: this pattern has been demonstrated for picture naming but effects in categorisation are less clear. We developed a paced serial semantic task (PSST), in which participants identified category members among distracters. Performance in healthy young adults deteriorated with ongoing retrieval for non-repeated words belonging to functional categories (e.g., picnic), taxonomic categories (e.g., animal) and feature-based categories (e.g., colour red – ‘tomato’, ‘post box’). This decline was greatest at fast presentation speeds (when there was less time to overcome competition/inhibition) and for strongly associated targets (which may have accrued more inhibition to facilitate earlier target categorisation). Deteriorating performance was also seen across words and pictures, consistent with a conceptual locus. We observed a release from deteriorating categorisation following a switch to a new category, demonstrating that this was not a general effect of time on task. Patients with semantic aphasia, who have deficient semantic control, maintained their performance throughout the categories, unlike younger adults: this finding is hard to reconcile with accounts of declining performance that propose a build-up of competition, since the patients should have had greater difficulty resolving such competition. These results instead suggest that declining performance on our goal-driven categorisation task was linked to the use of a controlled retrieval strategy by healthy young adults. Patients may not have inhibited related non-target knowledge to facilitate initial categorisation like younger volunteers, and consequently they were less vulnerable to declining comprehension in this paradigm. Together, these results demonstrate circumstances which produce declines in continuous categorisation in healthy adults.

Divided attention reduces resistance to distraction at encoding but not retrieval

Older adults show implicit memory for previously seen distraction, an effect attributed to poor attentional control. It is unclear whether this effect results from lack of control over encoding during the distraction task, lack of retrieval constraint during the test task, or both. In the present study, we simulated poor distraction control in young adults using divided attention at encoding, at retrieval, at both times, or not at all. The encoding task was a 1-back task on pictures with distracting superimposed letter strings, some of which were words. The retrieval task was a word fragment completion task testing implicit memory for the distracting words. Attention was divided using an auditory odd digit detection task. Dividing attention at encoding, but not at retrieval, resulted in significant priming for distraction, which suggests that control over encoding processes is a primary determinant of distraction transfer in populations with low inhibitory control (e.g. older adults).

Cognitive Control As a Double-Edged Sword

Cognitive control, the ability to limit attention to goal-relevant information, aids performance on a wide range of laboratory tasks. However, there are many day-to-day functions which require little to no control and others which even benefit from reduced control. We review behavioral and neuroimaging evidence demonstrating that reduced control can enhance the performance of both older and, under some circumstances, younger adults. Using healthy aging as a model, we demonstrate that decreased cognitive control benefits performance on tasks ranging from acquiring and using environmental information to generating creative solutions to problems. Cognitive control is thus a double-edged sword - aiding performance on some tasks when fully engaged, and many others when less engaged.

The effects of value on context-item associative memory in younger and older adults

Valuable items are often remembered better than items that are less valuable by both older and younger adults, but older adults typically show deficits in binding. Here, we examine whether value affects the quality of recognition memory and the binding of incidental details to valuable items. In Experiment 1, participants learned English words each associated with a point-value they earned for correct recognition with the goal of maximizing their score. In Experiment 2, value was manipulated by presenting items that were either congruent or incongruent with an imagined state of physiological need (e.g., hunger). In Experiment 1, point-value was associated with enhanced recollection in both age groups. Memory for the color associated with the word was in fact reduced for high-value recollected items compared with low-value recollected items, suggesting value selectively enhances binding of task-relevant details. In Experiment 2, memory for learned images was enhanced by value in both age groups. However, value differentially enhanced binding of an imagined context to the item in younger and older adults, with a strong trend for increased binding in younger adults only. These findings suggest that value enhances episodic encoding in both older and younger adults but that binding of associated details may be reduced for valuable items compared to less valuable items, particularly in older adults. (PsycINFO Database Record

Time of day effects on the use of distraction to minimise forgetting

Recent research found that implicit rehearsal of distraction can reduce forgetting for older adults, in part due to their inefficient regulation of irrelevant information. Here, we investigated whether young adults' memory can also benefit from critical information presented as distraction. Participants recalled a list of words initially and then again after a 15-min delay, with some of the critical studied words exposed as distraction during the delay. We tested young adults at an optimal versus non-optimal time of day, the latter a condition intended to mirror patterns of those with reduced attention regulation. We also varied task instruction to assess whether awareness of an upcoming memory task would influence implicit rehearsal of distraction. The task instruction manipulation was ineffective, but desynchronising time of testing and period of optimal cognitive arousal resulted in a memory benefit. Young adults tested at a non-optimal time showed minimal forgetting of words repeated as distraction, while those tested at an optimal time showed no memory benefit for these items, consistent with research suggesting that attention regulation is greatly affected by circadian arousal.

Do young adults show conceptual knowledge of previous distractors?

Using implicit tests, older adults have been found to retain conceptual knowledge of previously seen task-irrelevant information. While younger adults typically do not show the same effect, evidence from one study [Gopie, N., Craik, F. I. M., & Hasher, L. (2011). A double dissociation of implicit and explicit memory in younger and older adults. Psychological Science, 22, 634-640. doi: 10.1177/0956797611403321 ] suggests otherwise. In that study, young adults showed greater explicit than implicit memory for previous distractors on a word fragment completion task. This was interpreted as evidence for maintaining access to previous conceptual knowledge of the distractors. Here, we report two failures to replicate that original finding, followed by a third study designed to test directly whether young adults use conceptual-level information that was previously irrelevant. Our findings agree with others that young adults show weak to no evidence of conceptual knowledge of previously irrelevant information.

Costs of Selective Attention: When Children Notice What Adults Miss

One of the lawlike regularities of psychological science is that of developmental progression-an increase in sensorimotor, cognitive, and social functioning from childhood to adulthood. Here, we report a rare violation of this law, a developmental reversal in attention. In Experiment 1, 4- to 5-year-olds ( n = 34) and adults ( n = 35) performed a change-detection task that included externally cued and uncued shapes. Whereas the adults outperformed the children on the cued shapes, the children outperformed the adults on the uncued shapes. In Experiment 2, the same participants completed a visual search task, and their memory for search-relevant and search-irrelevant information was tested. The young children outperformed the adults with respect to search-irrelevant features. This demonstration of a paradoxical property of early attention deepens current understanding of the development of attention. It also has implications for understanding early learning and cognitive development more broadly.

Age-Related Differences in Associative Learning of Landmarks and Heading Directions in a Virtual Navigation Task

Previous studies have showed that spatial memory declines with age but have not clarified the relevance of different landmark cues for specifying heading directions among different age groups. This study examined differences between younger, middle-aged and older adults in route learning and memory tasks after they navigated a virtual maze that contained: (a) critical landmarks that were located at decision points (i.e., intersections) and (b) non-critical landmarks that were located at non-decision points (i.e., the sides of the route). Participants were given a recognition memory test for critical and non-critical landmarks and also given a landmark-direction associative learning task. Compared to younger adults, older adults committed more navigation errors during route learning and were poorer at associating the correct heading directions with both critical and non-critical landmarks. Notably, older adults exhibited a landmark-direction associative memory deficit at decision points; this was the first finding to show that an associative memory deficit exist among older adults in a navigational context for landmarks that are pertinent for reaching a goal, and suggest that older adults may expend more cognitive resources on the encoding of landmark/object features than on the binding of landmark and directional information. This study is also the first to show that older adults did not have a tendency to process non-critical landmarks, which were regarded as distractors/irrelevant cues for specifying the directions to reach the goal, to an equivalent or larger extent than younger adults. We explain this finding in view of the low number of non-critical cues in our virtual maze (relative to a real-world urban environment) that might not have evoked older adults’ usual tendency toward processing or encoding distractors. We explain the age differences in navigational and cognitive performance with regards to functional and structural changes in the hippocampus and parahippocampus, and recommend further investigations into the functional connectivity between the prefrontal cortex and hippocampus for a better understanding of the landmark-direction associative learning among the elderly. Finally, it is hoped that the current behavioral findings will facilitate efforts to identify the neural markers of Alzheimer’s disease, a disease that commonly involves navigational deficits.

Cultural differences in visual attention: Implications for distraction processing

We investigated differences between participants of East Asian and Western descent in attention to and implicit memory for irrelevant words which participants were instructed to ignore while completing a target task (a Stroop Task in Experiment 1 and a 1-back task on pictures in Experiment 2). Implicit memory was measured using two conceptual priming tasks (category generation in Experiment 1 and general knowledge in Experiment 2). Participants of East Asian descent showed reliable implicit memory for previous distractors relative to those of Western descent with no evidence of differences on target task performance. We also found differences in a Corsi Block spatial memory task in both studies, with superior performance by the East Asian group. Our findings suggest that cultural differences in attention extend to task-irrelevant background information, and demonstrate for the first time that such information can boost performance when it becomes relevant on a subsequent task.

A retroactive spatial cue improved VSTM capacity in mild cognitive impairment and medial temporal lobe amnesia but not in healthy older adults

Visual short-term memory (VSTM) is a vital cognitive ability, connecting visual input with conscious awareness. VSTM performance declines with mild cognitive impairment (MCI) and medial temporal lobe (MTL) amnesia. Many studies have shown that providing a spatial retrospective cue ("retrocue") improves VSTM capacity estimates for healthy young adults. However, one study has demonstrated that older adults are unable to use a retrocue to inhibit irrelevant items from memory. It is unknown whether patients with MCI and MTL amnesia will be able to use a retrocue to benefit their memory. We administered a retrocue and a baseline (simultaneous cue, "simucue") task to young adults, older adults, MCI patients, and MTL cases. Consistent with previous findings, young adults showed a retrocue benefit, whereas healthy older adults did not. In contrast, both MCI patients and MTL cases showed a retrocue benefit--the use of a retrocue brought patient performance up to the level of age-matched controls. We speculate that the patients were able to use the spatial information from the retrocue to reduce interference and facilitate binding items to their locations.