Inhibitory processes in young and older adults in a picture-word task

Abstract

The present study examines changes in healthy young and healthy older adults in the ability to inhibit partially activated information in a picture/word interference paradigm. On each trial, subjects received a cue (i.e., the word PICTURE or WORD) indicating which of two stimuli the subject should attend to in an upcoming picture/word display. the display always contained a superimposed picture and word (e.g., a picture of a DEER with the word TEA printed on it). Following display offset, and depending upon the initial precue, either a test picture (e.g., KETTLE) or a test word (e.g., MOOSE) was presented. the subject's task was to determine as quickly and as accurately as possible whether the test stimulus was related to the cued dimension of the earlier picture/word display. the speed to reject an unrelated test item (e.g., picture of a KETTLE when the precue was PICTURE) that was related to the ignored dimension of the picture/word display (e.g., the word TEA in the picture/word display) was used as an index of the efficiency of the inhibitory system. the results indicated that older adults had more difficulty than younger adults inhibiting a to-be-ignored word when it was related to a picture test item, but did not have more difficulty inhibiting a to-be-ignored picture when it was related to a word test item. the results indicate that an age-related deficit in the control of interfering information is dependent upon the fluency of the processing routes.     

The transient nature of executive control processes in younger and older adults

In this paper I review data from recent studies supporting the hypothesis that executive control processes fluctuate in efficiency over time and that these fluctuations are more pervasive in older than younger adults. Patterns of response accuracy in tasks requiring selective attention and prospective memory reveal that lapses of intention are often preceded and followed by periods of goal-directed action. Analysis of response time distributions reveals that increased performance variability in older adults for task conditions requiring executive control results from an increase in the degree of positive skewing of the distribution. Together, these findings lead to the suggestion that disruptions of executive control processes supporting performance in demanding tasks are temporally limited in nature. Data from recent neurophysiological studies indicates a possible role of the prefrontal cortex in maintaining optimal levels of executive control.     

A comparison of higher order auditory processes in younger and older adults

The authors conducted 3 experiments investigating the effects of aging on higher order auditory processes. They compared younger and older adults with respect to (a) their auditory channel capacity, (b) the extent of their top-down control over auditory gain, and (c) their ability to focus attention on a narrow band of frequencies. To ensure that subclinical cochlear processing deficits in older adults (e.g., higher thresholds, poorer discrimination of frequency and intensity differences) did not limit performance, the authors used only stimuli that were perfectly discriminable by all participants. No age differences were found in any of these experiments, suggesting that some higher order auditory processes (e.g., top-down control over auditory gain, auditory attention) are preserved in normal aging, despite numerous age-related declines in peripheral auditory functionality.     

Stereotype threat strengthens automatic recall and undermines controlled processes in older adults

The threat of being judged stereotypically (stereotype threat) may impair memory performance in older adults, thereby producing inflated age differences in memory tasks. However, the underlying mechanisms of stereotype threat in older adults or other stigmatized groups remain poorly understood. Here, we offer evidence that stereotype threat consumes working memory resources in older adults. More important, using a process-dissociation procedure, we found, for the first time, that stereotype threat undermines the controlled use of memory and simultaneously intensifies automatic response tendencies. These findings indicate that competing models of stereotype threat are actually compatible and offer further reasons for researchers and practitioners to pay special attention to age-related stereotypes during standardized neuropsychological testing.     

Strategic encoding and retrieval processes in verbal recall among middle-aged and older adults

The authors used an analysis of individual differences to examine the role of executive control in strategic encoding and retrieval in verbal recall. Participants enrolled in the Louisiana Healthy Aging Study completed measures of working memory (WM), cognitive status, vocabulary, and free recall of words. Indices of clustering in free recall were calculated to permit inferences on strategic encoding and retrieval processes. We hypothesized that WM would be more strongly associated with strategic encoding and retrieval metrics than vocabulary based on the assumption that successful remembering requires executive control in WM. Regression analyses, together with a variance portioning procedure, confirmed that WM had comparable levels of unique and shared variance with the strategic encoding and retrieval metrics, and both exceeded vocabulary. Theoretical and clinical implications of these data are considered, with the suggestion of future research in lifespan samples as opposed to exclusively young adult or older adult samples.     

Stress and inflammation among older adults: The moderating role of religiosity

Chronic stress weakens the immune system and leads to heightened bodily inflammation, which in turn is linked with serious health conditions. This study examined whether religiosity moderates the relationship between stress and inflammation (measured by C-reactive Protein (CRP)). A sample of 4,734 community-dwelling older adults was drawn from the 2006 wave of the Health and Retirement Study. Logistic regression was used to analyze the relationship between chronic stress (8-item index), inflammation (high CRP level), and religiosity (organizational, nonorganizational, and intrinsic), controlling for other factors. Higher levels of stress were significantly associated with high inflammation/CRP (p = .039). Further, intrinsic religiosity acted as a moderator of this relationship (p = .024), such that the relationship between stress and inflammation is lessened for persons with higher levels of intrinsic religiosity. Higher intrinsic religiosity attenuated the effects of stress on inflammation, suggesting that individuals with stronger religious commitment/motivation may better cope with stress.     

Global coherence in younger and older adults: Influence of cognitive processes and discourse type

The purpose of the present research was to examine the influence of cognitive processes on discourse global coherence ability measured across different discourse tasks and collected from younger (n = 40; 20–39 years) and older (n = 40; 70–87 years) cognitively healthy adults. Study participants produced oral language samples in response to five commonly used discourse elicitation tasks and they were analyzed for maintenance of global coherence. Participants also completed memory and attention measures. Group differences on the global coherence scale were found for only one type of discourse—recounts. Across discourse elicitation tasks the lowest global coherence scores were found for recounts compared to the other discourse elicitation tasks. The influence of cognitive processes on maintenance of global coherence differed for the two age groups. For the younger group, there were no observed significant relationships. For the older group, cognitive measures were related to global coherence of stories and procedures.     

Specific effects of the Trier Social Stress Test on speech fluency in young and older adults

The notion that speech becomes less fluent during stressful speaking conditions has received little empirical test, and no research has tested this relationship in older adult participants. We analyzed speeches produced during the Trier Social Stress Test (TSST) or during a less stressful placebo (pTSST) version of the task. We measured young and older adults’ speech fillers (e.g., um), unfilled pauses (at least 1 s in duration), and other disfluencies (e.g., repetitions, repairs). Neither young nor older adult participants rated themselves as having greater stress in the TSST than pTSST condition, but behavioral effects were obtained. Participants in the TSST condition produced more mid-phrase speech fillers and unfilled pauses than participants in the pTSST condition. Young adults produced more unfilled pauses than older adults overall, and older adults produced more mid-phrase fillers than young adults. Critically, age group interacted with experimental condition, such that older speakers produced disproportionately more mid-phrase fillers than young adults in the TSST compared to the pTSST condition. In sum, the negative effects of the TSST on fluency were generally similar across age, but this specific age-related increase in mid-phrase fillers indicates that older adults’ word retrieval may have been particularly negatively affected. Findings are generally consistent with previous research and add to understanding of how factors internal to the speaker (i.e., demographic, personality, and cognitive variables) and factors external to the speaker (i.e., variables regarding the situation, context, or content of speech) combine to affect speech fluency.     

Semantic priming in young and older adults: evidence for age constancy in automatic and attentional processes

Automatic and attentional components of semantic priming and the relation of each to episodic memory were evaluated in young and older adults. Category names served as prime words, and the relatedness of the prime to a subsequent lexical decision target was varied orthogonally with whether the target category was expected or unexpected. At a prime-target stimulus-onset asynchrony (SOA) of 410 ms, target words in the same category had faster lexical decision latencies than did different category targets. This effect was not significant at a 1,550-ms SOA and was attributed to automatic processes. Expected category targets had faster latencies than unexpected category targets at the 410-ms SOA, and the magnitude of the effect increased at the 1,550-ms SOA. This effect was attributed to attentional processes. These patterns of priming were obtained for both age groups, but in a surprise memory test older adults had poorer recall of primes and targets. We discuss the implications of these results for the hypothesis that older adults suffer deficits in selective attention and for the related hypothesis that attentional deficits impair semantic processing, which causes memory decrements in old age.     

The impact of beliefs about face recognition ability on memory retrieval processes in young and older adults

This study examined whether beliefs about face recognition ability differentially influence memory retrieval in older compared to young adults. Participants evaluated their ability to recognise faces and were also given information about their ability to perceive and recognise faces. The information was ostensibly based on an objective measure of their ability, but in actuality, participants had been randomly assigned the information they received (high ability, low ability or no information control). Following this information, face recognition accuracy for a set of previously studied faces was measured using a remember–know memory paradigm. Older adults rated their ability to recognise faces as poorer compared to young adults. Additionally, negative information about face recognition ability improved only older adults' ability to recognise a previously seen face. Older adults were also found to engage in more familiarity than item-specific processing than young adults, but information about their face recognition ability did not affect face processing style. The role that older adults' memory beliefs have in the meta-cognitive strategies they employ is discussed.     

Personality and sexuality in older adults

Objective: This study explored cross-time associations between personality and multiple components of sexual functioning and behaviour in a large cohort of older adults (n = 5745).

Design: Participants (M_age = 65.57 ± 8.28 years) completed questionnaires in 2010 and 2012.

Main outcome measures: Outcomes explored included sexual attitudes, sexual activity, sexual satisfaction, lifetime sexual partners, sexual orientation and sexual dysfunction.

Results: We found that higher levels of openness and lower levels of agreeableness were related to more liberal attitudes toward sex, a greater number of sexual partners, a higher sex drive, more frequent sexual activity, lower levels of sexual dysfunction and (for women) a greater tendency towards homosexuality. Higher levels of conscientiousness were also related to more conservative attitudes towards sex, lower levels of sexual dysfunction and a greater tendency towards heterosexuality. For sexually active older adults, higher levels of extraversion and lower levels of neuroticism were related to greater sexual satisfaction. Higher levels of extraversion and lower levels of conscientiousness were also related to a greater number of sexual partners in men but not women.

Conclusion: These findings provide evidence that personality is an important correlate of sexual functioning and behaviour in older adults.     

Inhibitory processes and spoken word recognition in young and older adults: the interaction of lexical competition and semantic context.

Two experiments were conducted to examine the importance of inhibitory abilities and semantic context to spoken word recognition in older and young adults. In Experiment 1, identification scores were obtained in 3 contexts: single words, low-predictability sentences, and high-predictability sentences. Additionally, identification performance was examined as a function of neighborhood density (number of items phonetically similar to a target word). Older adults had greater difficulty than young adults recognizing words with many neighbors (hard words). However, older adults also exhibited greater benefits as a result of adding contextual information. Individual differences in inhibitory abilities contributed significantly to recognition performance for lexically hard words but not for lexically easy words. The roles of inhibitory abilities and linguistic knowledge in explaining age-related impairments in spoken word recognition are discussed.     

Relational integration in older adults

Reasoning requires making inferences based on information gleaned from a set of relations. The relational complexity of a problem increases with the number of relations that must be considered simultaneously to make a correct inference. Previous work (Viskontas, Morrison, Holyoak, Hummel, & Knowlton, ) has shown that older adults have difficulty integrating multiple relations during analogical reasoning, especially when required to inhibit irrelevant information. We report two experiments that examined the ability to integrate multiple relations in younger, middle-aged, and older adults performing two other reasoning tasks. These tasks systematically varied relational complexity, and required either inductive reasoning (a version of the Raven's Matrices Task) or transitive inference. Our results show that as people age they have increasing difficulty in solving problems that require them to integrate multiple relations. This difficulty may stem from a decrease in working memory capacity.     

Search and selection processes in implicit and explicit word-stem completion performance in young, middle-aged, and older adults

In the present investigation, we sought to (1) replicate previous reports of impaired word-stem completion (WSC) priming and cued recall performance in older adults, (2) gain a better understanding of the differential roles of search and selection processes in implicit and explicit WSC, and (3) determine the particular aspects of WSC performance that are influenced by age. Experiment 1 demonstrated that older adults primed and recalled fewer items on a WSC task than middle-aged adults did, who in turn primed and recalled fewer items than young adults did. A series of item analyses indicated that choice of a stem completion is influenced by two independent sources of information: the familiarity of the completion reflected by word frequency and the cue-specific match between the stem and the completion word based on the common pronunciation of the stem. Experiment 2 demonstrated that older adults utilized cue-specific matching to the same degree as young and middle-aged adults. However, the impact of target familiarity changed across the lifespan. Older adults produced and recalled high-frequency targets as well as young adults but produced and recalled fewer low-frequency targets than did young participants. The results are consistent with the view that older adults rely on familiarity to a greater degree than do young adults.     

Visuomotor binding in older adults

Action integration is the process through which actions performed on a stimulus and perceptual aspects of the stimulus become bound as a unitary object. This process appears to be controlled by the dopaminergic system in the prefrontal cortex, an area that is known to decrease in volume and dopamine functioning in older adults. Although the decline should lead to reduced action integration in older adults, we found equivalent integration in both young and older adults. This indicates that older adults may be able to compensate for their dopaminergic deficiencies by activating additional neural networks that are not used by young adults.     

Representational momentum in older adults

Humans have a tendency to perceive motion even in static images that simply “imply” movement. This tendency is so strong that our memory for actions depicted in static images is distorted in the direction of implied motion - a phenomenon known as representational momentum (RM). In the present study, we created an RM display depicting a pattern of implied (clockwise) rotation of a rectangle. Young adults viewers’ memory of the final position of the test rectangle was biased in the direction of continuing rotation, but older adults did not show a similar memory bias. We discuss several possible explanations for this group difference, but argue that the failure of older adults to shown an RM effect most likely reflects age-related changes in areas of the brain involved in processing real and implied motion.     

老年人群的韵律感知

老龄化导致听觉系统、认知功能有所衰退。老年人群的言语理解能力减弱, 韵律信息解析存在困难。老年人对重音、语调、语速等语言韵律感知能力退化, 对情感韵律的加工也出现问题, 特别是消极情绪韵律加工减退较快。老年疾病进一步加深韵律加工难度, 韵律感知呈现出与特定疾病的相关性。未来研究需考察不同语言背景老年人群的韵律感知表现与机制、复杂交流环境的影响、韵律感知障碍对老年疾病的预测、韵律感知的早期干预与复健等问题。     

Judgments of blame and forgiveness: A comparison of young adults,older adults,and older adults with dementia

IntroductionAlzheimer's disease may modify moral judgment.ObjectiveIn two studies, we assessed the impact of dementia on blame and forgiveness. Study 1 compared the ways in which young adults, older adults, and older adults with dementia cognitively integrated two factors. Study 2 assessed the number of different factors that older adults with dementia were able to integrate during these moral judgments.MethodThe participants recorded their moral judgements in a blame task and in a forgiveness task. In study 1, the two questionnaires contained scenarios built from the combination of two factors. In study 2, the participants were confronted with the same tasks under three different conditions with scenarios that combined three, four or five factors.ResultsThe data from study 1 showed that the older adults with dementia did not combine the two factors in the same way as young adults did: the combination depended on the type of moral judgment. Study 2 revealed differences in moral judgment between older adults with dementia and adults without dementia in all tasks (i.e. with three, four or five factors combined).ConclusionDementia has an impact on moral judgments. Moral judgment among people with dementia is both task- and condition-dependant.     

Sustained-attention capacity in young and older adults

The sustained-attention capacity of young (21-29 years) and older (65-78 years) adults was examined using a high-event rate digit-discrimination vigilance task presented at three levels of stimulus degradation. Increased stimulus degradation led to a reduction in the hit rate and to a greater decline in hit rate over blocks (increased vigilance decrement). Sensitivity (d') declined over blocks only at the highest level of stimulus degradation. Older adults had a lower hit rate and showed greater vigilance decrement than young adults, particularly when stimuli were highly degraded. However, both age groups showed the same pattern of stability in sensitivity when stimulus degradation was moderate, and sensitivity decrement over time when stimulus degradation was high. The results suggest that the process of sustained allocation of capacity--as reflected in temporal changes in sensitivity--operates similarly in young and older adults.     

Memory complaints in younger and older adults

Two samples of older and younger subjects were administered a series of memory tasks and questionnaires tapping their perceptions about their own memory functioning. As in previous research, memory performance was usually better in the younger than in the older sample. In contrast, perceptions about memory varied little as a function of age, and these subjective reports were not related to objective memory performances. These results are relevant to theories that metacognition plays an important role in mediating performance declines with advancing age. If metacognition is implicated in age-related memory differences, it is some aspect of metacognition other than long-term beliefs about memory functioning (e. g. short-term perceptions that occur while attempting to perform memory tasks).