How do health and biological age influence chronological age and sex differences in cognitive aging: moderating, mediating, or both?

Much research on cognitive competence in normal older adults has documented age and sex differences. The authors used new cross-sectional data from the Victoria Longitudinal Study (VLS) (n=386; age 61 to 95 years) to examine how health and biological age influence age and sex differences in cognitive aging. The authors found evidence for both moderating and mediating influences. Age differences were moderated by health status, such that the negative effects of age were most pronounced among participants of relatively better health. Sex differences were moderated by health and were more pronounced among participants reporting comparatively poorer health. Although health mediated a notable amount of age-related cognitive variation, BioAge mediated considerably more variance, even after statistical control for differences in health. A complex pattern emerged for the mediation of sex differences: Although BioAge accounted for sex-related variation in cognitive performance, health operated to suppress these differences. Overall, both health and BioAge predicted cognitive variation independently of chronological age.     

Biomarkers, health, lifestyle, and demographic variables as correlates of reaction time performance in early, middle, and late adulthood

We aimed to identify demographic, health, and biomarker correlates of reaction time performance and to determine whether biomarkers explained age differences in reaction time performance. The sample comprised three representative cohorts aged 20-24, 40-44, and 60-64 years, including a total of 7,485 participants. Reaction time measures of intraindividual variability and latency were used. The measure of intraindividual variability used was independent of mean reaction time. Older adults were more variable than younger adults in choice reaction time performance but not simple reaction time performance. The most important correlates of reaction time performance after gender and education were biological markers such as forced expiratory volume at one second, grip strength, and vision. Few measures of physical or mental health or lifestyle were associated with poorer performance on reaction time measures. Biomarkers explained the majority of age-related variance in simple reaction time and a large proportion of variance in choice reaction time. We conclude that for the ages studied, biomarkers are more important than health factors for explaining age differences in reaction time performance.     

Contents Index Volume 8

In a group of 62 young and 75 older subjects, LISREL models were used to predict ordered list recall from age category, self-reported strategy use and selected cognitive abilities. It was found that: (a) age differences in the strategies of associating and repetition/testing were completely explained by speed of mental processing and associative memory; (b) only these two age-related strategies were efficacious strategies, the one not age-related strategy (concentrating) was not; (c) a large proportion of the age-related variance in list recall performance was mediated by speed and associative memory; and (d) this influence of speed and associative memory on ordered list recall was partly mediated by strategies. These results support a moderate version of the production deficiency explanation of memory aging, in which age differences in efficacious strategy use are explained by age differences in basic cognitive abilities.     

Plasticity of memory for new learning in very old age: a story of major loss?

Longitudinal survivors of the Berlin Aging Study (N = 96, mean age = 84 years, range 75-101 years) were instructed and trained in a mnemonic skill to examine plasticity of episodic memory performance in very old age. Performance gains after mnemonic instruction were modest, and most individuals were unable to further enhance their performance during 4 sessions of mnemonic practice. Whereas the proportion of variance explained by measures from the broad fluid-ability domain (e.g., perceptual speed) increased with training, the proportion of variance explained by crystallized-ability domain (e.g., word knowledge) and sociobiographical variables decreased. Furthermore, prior 6-year longitudinal changes (loss) in perceptual speed predicted individual differences in plasticity. Results suggest that aging-induced biological factors are a prominent source of individual differences in cognitive plasticity in very old age.     

Predictors of time-based prospective memory in children

This study identified age differences in time-based prospective memory performance in school-aged children and explored possible cognitive correlates of age-related performance. A total of 56 7- to 12-year-olds performed a prospective memory task in which prospective memory accuracy, ongoing task performance, and time monitoring were assessed. Additional tests of time estimation, working memory, task switching, and planning were performed. Results showed a robust relationship between age and prospective memory performance even after controlling for ongoing task performance. Developmental differences in time monitoring were also observed, with older children generally adopting a more strategic monitoring strategy than younger children. The majority of age-related variance in prospective memory task performance could be explained by cognitive resources, in particular planning and task switching. In contrast, no further independent contribution of time estimation was observed. Findings are in line with the development of strategic behavior, as well as executive functioning, in school-aged children.     

ADAPTABILITY TO CHANGING TASK CONTEXTS: EFFECTS OF GENERAL COGNITIVE ABILITY, CONSCIENTIOUSNESS, AND OPENNESS TO EXPERIENCE

We examined the extent to which cognitive ability, Conscientiousness, and Openness to Experience predict decision-making performance prior to and after unforeseen changes in the task context. Seventy-three undergraduates made decisions on a series of 75 problems during a 3-hour computerized simulation. Unbeknownst to participants, the rules used in determining correct decisions changed after problems 25 and 50. Effects of the individual differences on decision-making performance became significantly stronger after the changes. Only cognitive ability explained variance in prechange performance. Individuals with higher cognitive ability made better decisions. After the change, the cognitive ability effect increased and the effects of Conscientiousness and Openness became statistically significant. As expected, those with high Openness made better decisions. Unexpectedly, those with low Conscientiousness made better decisions. Subsequent analyses revealed that this surprising effect for Conscientiousness was due to the traits reflecting dependability (i.e., order, dutiful-ness, deliberation) rather than volition (i.e., competence, achievement striving, self-discipline).     

Assessing mental flexibility with a new word recognition test

This paper presents the development and preliminary evaluation of a new word recognition test (WRT) designed to measure individual differences in mental flexibility, defined as the ability to solve novel problems in unfamiliar settings. Conceptually designed to simulate problem solving in real world performance situations, the test was developed to recruit fluid and reproductive abilities and the interplay between convergent and divergent thinking. It is based on a framework that integrates and extends previous theoretical and methodological approaches to the study of cognitive ability and creative cognition. The WRT was administered with various cognitive ability and criterion measures to an undergraduate student sample (n = 266). Results provide preliminary evidence of construct validity. WRT scores correlated as expected with reference measures of cognitive ability, creative performance, and college performance (GPA). Regression analyses showed the WRT explained an additional 4.5% of variance in college performance over and above traditional cognitive ability measures that take up to five times as long to administer. Results suggest further study is warranted given the potential for its contribution to basic research and applied use.     

Facets of psychopathy, heart rate variability and cognitive function

The aim of the present study was to investigate whether the four facets of Hare's Psychopathy Checklist-Revised (PCL-R; Hare, 1991; Bolt, Hare, Vitale, & Newman, 2004) were related to physiological and cognitive mechanisms. Fifty-three male prisoners participated in this study. Physiological responses were measured as heart rate variability (HRV) and heart rate (HR). Cognitive functions were measured using a continuous performance test (CPT; California Computerized Assessment Package, Abbreviated version) and a working memory test (WMT); based on Baddeley & Hitch (1974). The regression analysis of the HRV revealed that the interpersonal facet explained most of the variance during baseline (28%), CPT (16%), and WMT (12%). This was also true for the HR data during baseline (28%), CPT (20%), WMT (10%), and recovery (13%). The antisocial facet explained 10% of the variance only during baseline. Subjects scoring high compared to low on the interpersonal facet also showed better cognitive functioning. The study suggests that the different facets were differently associated with both physiological and cognitive functions.     

Age-related variance in decisions under ambiguity is explained by changes in reasoning,executive functions,and decision-making under risk

Previous literature has explained older individuals’ disadvantageous decision-making under ambiguity in the Iowa Gambling Task (IGT) by reduced emotional warning signals preceding decisions. We argue that age-related reductions in IGT performance may also be explained by reductions in certain cognitive abilities (reasoning, executive functions). In 210 participants (18–86 years), we found that the age-related variance on IGT performance occurred only in the last 60 trials. The effect was mediated by cognitive abilities and their relation with decision-making performance under risk with explicit rules (Game of Dice Task). Thus, reductions in cognitive functions in older age may be associated with both a reduced ability to gain explicit insight into the rules of the ambiguous decision situation and with failure to choose the less risky options consequently after the rules have been understood explicitly. Previous literature may have underestimated the relevance of cognitive functions for age-related decline in decision-making performance under ambiguity.     

Aging and strategic retrieval in a cued-recall test: the role of executive functions and fluid intelligence

Cued-recall in episodic memory was investigated in relation to low and high cognitive support at retrieval, executive function level and fluid intelligence level in 81 healthy adults divided first into two age groups (young and elderly adults). The first analyses showed that age-related differences were greater when a low cognitive support was provided to recall the words. An individual index of loss of performance when the number of cues was decreased was then calculated. Hierarchical regression analysis revealed that the executive functions measure (perseverative errors on the Wisconsin Card Sorting Test) was a better candidate than the fluid intelligence measure (Cattell's culture fair test) to account for the age-related variance of the size of performance loss. These findings suggest that age differences in implementing strategic retrieval may be mainly due to a decline in executive functions.     

The mouse attentional-set-shifting task: A method for assaying successful cognitive aging?

Humans exhibit considerable variance in cognitive decline with age, with some exhibiting little disruption and others becoming significantly impaired. In aged rodents, individual differences in spatial memory have been used to identify putative compensatory mechanisms underlying successful hippocampal aging. However, there are few parallel rodent models of cognitive decline in frontal-cortex-mediated functions. We tested the hypothesis that, like aged humans, aged mice would exhibit greater variance in executive function measures, as compared with young mice. We examined the performance of young and aged C57BL/6N mice in the attentional-set-shifting task. Whereas young and old mice did not differ on trials-to-criterion performance, aged mice exhibited significantly greater variance in mean correct latency—selective to the extradimensional shifting stage—as compared with their younger counterparts. Thus, this task may be used to identify mechanisms underlying individual differences in decline of frontal-mediated performances with age.     

The sensory‐cognition association in adulthood: Different magnitudes for processing speed,inhibition, episodic memory,and false memory?

One hundred and forty-six participants (age range = 20-80) completed a battery of tests designed to measure visual acuity, processing speed, inhibition, episodic memory and false memory. The relations between visual acuity and general cognitive ability, as well as between visual acuity and the indicators of this construct, were evaluated with structural equation modeling. The measurement model confirmed that the indicators of the individual cognitive abilities could be grouped into a general cognitive functioning factor. However, the relation between episodic and false memory was not completely explained by the shared association with this general factor. Furthermore, visual acuity predicted approximately half of the age-related variance in the general cognition factor. Also, the proportion of age-related variance shared with vision was highest in inhibition and lowest in false memory. The results are discussed in the light of common cause accounts of cognitive aging.     

Are variations among subjects in lateral asymmetry real individual differences or random error in measurement? Putting variability in its place

The current research investigates sources of variability in subjects' asymmetry scores on commonly used laterality tasks. In particular, subjects' asymmetry scores on four bilateral tachistoscopic tasks and one free-vision task were entered into a principal component analysis (PCA) in order to investigate components that explain the maximum variance of the sample. The results indicate that about half of the variation (45.2%) in asymmetry scores on both tachistoscopic and free-vision tasks is attributable to individual differences in characteristic perceptual asymmetry. The amount of variance explained by this characteristic perceptual asymmetry component is similar in a sample of dextrals and a sample of sinistrals. No significant relation was revealed between individual differences in characteristic perceptual asymmetry and performance on various verbal and spatial cognitive tasks.     

Academic Performance of High School Students as a Function of Mental Capacity,Cognitive Style,Mobility‐Fixity Dimension,and Creativity

The purpose of this study is to explore how creativity and the cognitive variables (mental capacity, cognitive style & mobility‐fixity dimension) can explain academic performance of high school students. Students at a high school in Maturin (Venezuela) were tested to determine creativity (Torrance Tests), cognitive variables and academic performance. Results based on multiple regression analyses showed that the mobility‐fixity dimension was the most consistent predictor of academic performance, by explaining a significant amount of the variance in Spanish, English, Geography, Biology, Chemistry, Earth Science, Mathematics, Physics and the Mean score. Creativity scores explained a significant amount of the variance in Spanish, Geography, Earth Science and the Mean score. It appears that the mobility‐fixity dimension and creativity although related, perhaps represent different aspects of academic performance.     

Antecedents of Children's Performance on Class Inclusion Tasks: Some Zimbabwean Evidence

An analysis of covariance hierarchical regression procedure was used to examine children's performance on verbally presented classification tasks in relation to the children's socio-cultural background, age, level of schooling, and sex. Task perception and motivation were entered as covariates. A total of 296 black and white Zimbabwean children took part in the study. Social class membership, age, level of schooling, and sex explained a significant proportion of the variance in performance on the classification tasks, whereas cultural group membership did not. Implications for multicultural perspectives on children's cognitive development are discussed and suggestions made for further research.     

Age-related similarities and differences in monitoring spatial cognition

Spatial cognitive performance is impaired in later adulthood but it is unclear whether the metacognitive processes involved in monitoring spatial cognitive performance are also compromised. Inaccurate monitoring could affect whether people choose to engage in tasks that require spatial thinking and also the strategies they use in spatial domains such as navigation. The current experiment examined potential age differences in monitoring spatial cognitive performance in a variety of spatial domains including visual–spatial working memory, spatial orientation, spatial visualization, navigation, and place learning. Younger and older adults completed a 2D mental rotation test, 3D mental rotation test, paper folding test, spatial memory span test, two virtual navigation tasks, and a cognitive mapping test. Participants also made metacognitive judgments of performance (confidence judgments, judgments of learning, or navigation time estimates) on each trial for all spatial tasks. Preference for allocentric or egocentric navigation strategies was also measured. Overall, performance was poorer and confidence in performance was lower for older adults than younger adults. In most spatial domains, the absolute and relative accuracy of metacognitive judgments was equivalent for both age groups. However, age differences in monitoring accuracy (specifically relative accuracy) emerged in spatial tasks involving navigation. Confidence in navigating for a target location also mediated age differences in allocentric navigation strategy use. These findings suggest that with the possible exception of navigation monitoring, spatial cognition may be spared from age-related decline even though spatial cognition itself is impaired in older age.     

Relationships between physical exercise and cognitive abilities in older adults

We investigated relationships between physical exercise and the cognitive abilities of older adults. We hypothesized that the performance of vigorous exercisers would be superior to that of sedentary individuals on measures of reasoning, working memory, and reaction time. We gave a series of cognitive tasks to 62 older men and women who exercised vigorously and 62 sedentary men and women. Multivariate and univariate analyses of variance, with age and education as covariates, indicated that the performance of the exercisers was significantly better on measures of reasoning, working memory, and reaction time. Between-group differences persisted when vocabulary, on which the performance of exercisers was superior, was used as a third covariate. Subsequent analyses showed that neither self-rated health, medical conditions, nor medications contributed to the differences between exercise groups. Results suggest that the possible contribution of physical exercise to individual differences in cognition among older adults should be further investigated.     

Demographic, clinical, and neurocognitive correlates of everyday functional impairment in severe mental illness

Although cognitive deficits often accompany severe mental illness, their implications for everyday functioning remain poorly understood. In this study, an occupational therapist (OT) rated the everyday functioning of 105 adult psychiatric patients. Using demographic, clinical, and cognitive variables, the authors tested alternative models to account for the observed variability in OT ratings. Although age, education, and the presence of schizophrenia each contributed to a model that accounted for 27% of the variation in functional independence, adding terms for auditory divided attention and verbal learning increased the proportion of explained variance to 45% and decreased the beta weights for age and education--but not schizophrenia--to nonsignificant levels. These findings demonstrate the relevance of cognitive performance to everyday functioning in severe mental illness. They are discussed with respect to hypothesized determinants of psychiatric disability.     

Individual differences in children's emotion understanding: effects of age and language

Over the last two decades, it has been established that children's emotion understanding changes as they develop. Recent studies have also begun to address individual differences in children's emotion understanding. The first goal of this study was to examine the development of these individual differences across a wide age range with a test assessing nine different components of emotion understanding. The second goal was to examine the relation between language ability and individual differences in emotion understanding. Eighty children ranging in age from 4 to 11 years were tested. Children displayed a clear improvement with age in both their emotion understanding and language ability. In each age group, there were clear individual differences in emotion understanding and language ability. Age and language ability together explained 72% of emotion understanding variance; 20% of this variance was explained by age alone and 27% by language ability alone. The results are discussed in terms of their theoretical and practical implications.     

GENERAL MENTAL ABILITY,NARROWER COGNITIVE ABILITIES,AND JOB PERFORMANCE: THE PERSPECTIVE OF THE NESTED-FACTORS MODEL OF COGNITIVE ABILITIES

The nested-factors model is a well-established structural model of cognitive abilities in cognitive ability research but has not yet been used to investigate the role of cognitive abilities in job performance. Core assumptions of the nested-factors model are that a broad general mental ability (GMA) exists besides narrower abilities and that this GMA differs from the narrower cognitive abilities in breadth but not in subordination. The authors of this article propose that a recently emerging statistical technique—relative importance analysis—corresponds to the assumptions of the nested-factors model. To empirically study the implications of using the nested-factors model, the authors applied relative importance analysis to a meta-analytic matrix linking measures of 7 narrower cognitive abilities from an established ability taxonomy (Thurstone's primary mental abilities), GMA, and job performance. Results revealed that GMA accounted for 10.9% to 28.6% of the total variance explained in job performance and that GMA was not consistently the most important predictor. The discussion focuses on potential theoretical, methodological, and practical implications of the nested-factors model for personnel psychology.