Cross-Sectional versus Longitudinal Age Gradients of Tower of Hanoi Performance: The Role of Practice Effects and Cohort Differences in Education

ABSTRACT

We examined 5-year longitudinal changes in Tower of Hanoi (TOH) performance in a population-based sample of adults (35–85 years initially; n?=?1480). An age-matched sample (n?=?433) was included to estimate practice effects. The longitudinal age gradients differed substantially from the cross-sectional age gradients. This was the case even when practice effects, that were substantial in magnitude across the young/middle-aged groups, were controlled for. Instead of a continuous age-related deficit in performance from 35 and onwards, longitudinal data showed slowing of performance and increases of illegal moves past age 65. Cohort-related differences in educational attainment did not account for this discrepancy. Further analyses revealed a positive relation between practice-related gains and explicit memory of having performed the task at the first test occasion and a positive association between latent changes in TOH and Block Design, in line with cross-sectional findings. In conclusion, the results demonstrate a pattern of age-related changes indicating a late-onset decline of TOH performance and underscore the need to control for retest effects in longitudinal aging research.     

Stability, growth, and decline in adult life span development of declarative memory: cross-sectional and longitudinal data from a population-based study

Five-year changes in episodic and semantic memory were examined in a sample of 829 participants (35-80 years). A cohort-matched sample (N=967) was assessed to control for practice effects. For episodic memory, cross-sectional analyses indicated gradual age-related decrements, whereas the longitudinal data revealed no decrements before age 60, even when practice effects were adjusted for. Longitudinally, semantic memory showed minor increments until age 55, with smaller decrements in old age as compared with episodic memory. Cohort differences in educational attainment appear to account for the discrepancies between cross-sectional and longitudinal data. Collectively, the results show that age trajectories for episodic and semantic memory differ and underscore the need to control for cohort and retest effects in cross-sectional and longitudinal studies, respectively.     

Adult Age Differences in Tower of Hanoi Performance: Influence From Demographic and Cognitive Variables

We examined performance in a five-disk version of the Tower of Hanoi (TOH) puzzle, assumed to reflect executive functioning, in population-based samples ranging in age from 35 to 85 years (N ?=?2798). Univariate analyses revealed significant age effects across three TOH measures as reflected by an age-related increase in moves to solution, a gradual slowing of performance, and an increase in rule violations with advanced age. The age-related influence was eliminated, or reduced considerably, when controlling for demographic and cognitive background variables. Across the dependent measures, Block Design and a measure of episodic memory (recall) were the consistent predictors. No effects of education were detected, while significant gender differences, favoring males, were observed for two TOH measures. Taken together, the results suggest that age-related deficits observed in TOH performance reflects an age-related impairment in visuospatial ability in addition to impairments in executive functions.     

The fate of cognition in very old age: six-year longitudinal findings in the Berlin Aging Study (BASE)

The authors report full-information longitudinal age gradients in 4 intellectual abilities on the basis of 6-year longitudinal changes in 132 individuals (mean age at T1 = 78.27, age range = 70-100) from the Berlin Aging Study. Relative to the cross-sectional parent sample (N = 516, mean age at T1 = 84.92 years), this sample was positively selected because of differential mortality and experimental attrition. Perceptual speed, memory, and fluency declined with age. In contrast, knowledge remained stable up to age 90, with evidence for decline thereafter. Age gradients were more negative in old old (n = 66, mean age at T1 = 83.04) than in old (n = 66, mean age at T1 = 73.77) participants. Rates of decline did not differ reliably between men and women or between participants with high versus low life-history status. They conclude that intellectual development after age 70 varies by distance to death, age, and intellectual ability domain.     

Sustained attention in adulthood: a unique, large-sample, longitudinal and multicohort analysis using the Mackworth Clock-Test

A cross-sectional sample of men (n = 177) tested in 1962-1964, and men (n = 188) and women (n = 113) tested in 1980-1984, and a longitudinal sample (n = 53) of men tested in 1962-1964 and 1980-1984, were used to investigate age differences and 18-year age changes on a 62-min sensory vigilance task that made virtually no demand on memory, the Mackworth Clock-Test. Age differences and changes in the vigilance decrement were also examined. No age differences or changes were obtained for detection accuracy. Target response time showed significant age-related 18-year longitudinal changes and one significant cross-sectional age difference; the overall age effect was of a U-shaped function with a minimum at middle age. Age differences and changes were obtained in a measure of arousal: skin potential response latency; the overall age effect was also consistent with a U-shaped function. There was little consistent evidence of a differential effect of age on the vigilance decrement. Outcomes contradictory to Surwillo and Quilter (1964) and Quilter, Giambra, and Benson (1983) are reconciled through additional statistical analyses.     

Differential trajectories of age-related changes in components of executive and memory processes

Several studies have demonstrated age-related declines in general executive function and memory. In this study, we examined cross-sectional and longitudinal age effects in more specific cognitive processes that constitute executive function and memory. We postulated that, whereas some components of executive and memory functions would show age differences and longitudinal declines, other specific abilities would be maintained or even improve with repeated testing. In a sample of individuals ≥55 years old from the Baltimore Longitudinal Study of Aging, we found longitudinal declines in inhibition, manipulation, semantic retrieval, phonological retrieval, switching, and long-term memory over a maximum of 14 years follow-up. In contrast, abstraction, capacity, chunking, discrimination, and short-term memory were maintained or even improved longitudinally, probably due in part to repeated testing. Moreover, whereas several different abilities were correlated across participants' cross-sectional performance, longitudinal changes in performance showed more heterogeneous trajectories. Finally, compared with cross-sectional performance, longitudinal trajectories showed better distinction between participants with and those without later cognitive impairment. These results show that longitudinal cognitive aging of executive and memory functions is not a uniform process but a heterogeneous one and suggest that certain executive and memory functions remain stable despite age-related declines in other component processes. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

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

ABSTRACT

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

Mortality-Related Differences and Changes in Episodic Memory Among the Oldest Old: Evidence From a Population-Based Sample of Nonagenarians

We examined cross-sectional differences and longitudinal changes in episodic memory performance related to impending death among a group of very old people, aged 90–101 years. Participants were assessed at 3 measurement points across a 6-year interval. Three groups were identified: those who survived the entire follow-up period (n =40), those who died before the first follow-up (n =44), and those who died after the first follow-up (n =14). Participants completed a battery of episodic memory tasks consisting of face recognition, word recognition, word recall, and object recall with selective reminding. Those who survived performed better than those who were going to die in object recall at baseline. A Cox regression analysis, controlling age, revealed that object recall performance was significantly related to subsequent mortality status. Longitudinal analyses demonstrated significant 3-year decline for both face recognition and object recall, but no evidence of differential decline as a function of mortality group. Thus, longitudinal changes in memory preceding death were not as pronounced as the corresponding cross-sectional differences in this very old sample. In general, the results suggest that mortality-related memory deficits are present in extreme old age, although these deficits are relatively small and task-specific.     

ANTECEDENTS AND CONSEQUENCES OF PSYCHOLOGICAL WORKPLACE STRAIN DURING EXPATRIATION: A CROSS-SECTIONAL AND LONGITUDINAL INVESTIGATION

In this study, we examined nonlinear/interaction effects associated with the antecedents and consequences of psychological workplace strain, using cross-sectional ( N = 165) and longitudinal ( N = 133) data collected from Western expatriates in China. The results of this study indicate that family characteristics interact to affect the level of psychological workplace strain experienced by expatriates. In addition, we find an inverse u-curve relationship between psychological workplace strain and supervisory rated job performance for both cross-sectional and longitudinal analyses. Finally, the empirical results lend support to the hypothesized positive relationship between work adjustment measured at Time 1 and job performance measured at Time 2. Implications for expatriate adjustment research and practice are discussed.     

Individual differences in the development of sensation seeking and impulsivity during adolescence: further evidence for a dual systems model

Consistent with social neuroscience perspectives on adolescent development, previous cross-sectional research has found diverging mean age-related trends for sensation seeking and impulsivity during adolescence. The present study uses longitudinal data on 7,640 youth from the National Longitudinal Study of Youth Children and Young Adults, a nationally representative sample assessed biennially from 1994 to 2006. Latent growth curve models were used to investigate mean age-related changes in self-reports of impulsivity and sensation seeking from ages 12 to 24 years, as well individual differences in these changes. Three novel findings are reported. First, impulsivity and sensation seeking showed diverging patterns of longitudinal change at the population level. Second, there was substantial person-to-person variation in the magnitudes of developmental change in both impulsivity and sensation seeking, with some teenagers showing rapid changes as they matured and others maintaining relatively constant levels with age. Finally, the correlation between age-related changes in impulsivity and sensation seeking was modest and not significant. Together, these results constitute the first support for the dual systems model of adolescent development to derive from longitudinal behavioral data.     

Examination of the processing speed account in a population-based longitudinal study with narrow age cohort design

The processing speed account suggests that general slowing of mental processing speed results in an overall decline, especially age-related decline, in other cognitive domains. Support for the speed account comes mainly from cross-sectional studies with participants that vary in age (age-heterogeneous samples). This study investigated how well variations in processing speed predict change of episodic recall in a longitudinal framework and examined with the Narrow Age Cohort (NAC) design. Data were obtained from Betula, a population-based longitudinal study. Both 5-year (n= 490; Time 3 - Time 4) and 10-year follow-up results (n= 608; Time 1 - Time 3) were used. In both samples, which were subjected to prospective dementia screening, we found considerably weaker associations in longitudinal data compared to cross-sectional, and also weaker associations in age-homogeneous than in age-heterogeneous samples. The results provide little support for the speed account.     

Relationship between age and aspects of depression: consistency and reliability across two longitudinal studies

In this study, the authors examined cross-sectional and longitudinal age and gender differences in each of the Center for Epidemiological Studies Depression Scale's 4 subscales of depressive symptomatology. Two independent studies (Sample 1 = 2,076; Sample 2 = 943) were used for purposes of establishing stability of findings. Results indicate a reasonable degree of stability among adults under 70 years of age. However, there were significant age-related increases in somatic symptoms and lack of well-being after approximately 70 years of age, whereas symptoms related to depressed affect and interpersonal problems remained stable. Notably, depressive affect symptoms remained stable given significant age-related somatic changes. The addition of comorbid physical illness to the analysis did not reduce the association between age and depressive symptoms, indicating that part of the association was not substantially accounted for by physical health.     

Aging and cardiovascular reactivity to stress: longitudinal evidence for changes in stress reactivity

Although age differences in cardiovascular function are well documented, little research has provided longitudinal evidence for age-related changes in cardiovascular reactivity to stress. In this study, the authors report such data from a follow-up of their prior work (B. N. Uchino, D. Uno, J. Holt-Lunstad, & J. B. Flinders, 1999) with participants between the ages of 30 to 70 (n=108, mean follow-up=10 months, range=7 to 16 months). Results revealed longitudinal evidence for an age-related increase in systolic blood-pressure reactivity and parasympathetic withdrawal to acute stress. The implications of these findings are discussed in light of the increased cardiovascular disease risk with age, as well as the links between aging, emotions, and physiology.     

Is Age a Good Predictor of Research Productivity?

The research productivity of psychologists holding appointment in Australian universities was established at two times of measurement across groups defined with respect to chronological age and date of birth. The design allowed cross-sectional gradients to be contrasted over times of measurement, and longitudinal gradients to be compared across cohorts. Psychologists aged 26–35 years in 1970 showed no decline in publication rate between 1968–1970 and 1978–1980, while psychologists aged more than 35 years in 1970 showed a drop in research output over the 10-year period. However, a person's publication rate in 1978–1980 was better predicted by their past productivity (publication rate in 1968–1970) than by their age. These results are discussed in the context of factors that affect research productivity, as well as changes that will occur in the age distribution of Australian academics over the next 20 years.     

Cognition in the Berlin Aging Study (BASE): The First 10 Years

This paper summarizes and expands research on cognitive aging from the Berlin Aging Study (BASE), a longitudinal, multidisciplinary, and population-based investigation of old and very old individuals. First, we describe previously reported research on five key themes: (a) experimental and mortality-associated components of longitudinal selectivity; (b) comparisons between cross-sectional and cross-sectional/longitudinal convergence age gradients; (c) old-age dedifferentiation of inter-individual differences; (d) possible reasons for the age-based increase in the link between intellectual and sensory domains; and (e) limits to cognitive plasticity in very old age. Second, we make use of multilevel modeling to determine the magnitude and direction of retest effects. Retest effects are classified as either flat (step function from the first to the second measurement occasion) or growing (linear increase after the first measurement occasion). Five of the eight longitudinally administered cognitive tests are found to display significant retest effects of either or both types. Retest adjustment increased the linear negative and decreased the quadratic negative component of cross-sectional/longitudinal convergence gradients in measures of intellectual abilities.     

Only time will tell: cross-sectional studies offer no solution to the age-brain-cognition triangle: comment on Salthouse (2011)

Salthouse (2011) critically reviewed cross-sectional and longitudinal relations among adult age, brain structure, and cognition (ABC) and identified problems in interpretation of the extant literature. His review, however, missed several important points. First, there is enough disparity among the measures of brain structure and cognitive performance to question the uniformity of B and C vertices of the ABC triangle. Second, age differences and age changes in brain and cognition are often nonlinear. Third, variances and correlations among measures of brain and cognition frequently vary with age. Fourth, cross-sectional comparisons among competing models of ABC associations cannot disambiguate competing hypotheses about the structure and the range of directed and reciprocal relations between changes in brain and behavior. We offer the following conclusions, based on these observations. First, individual differences among younger adults are not useful for understanding the aging of brain and behavior. Second, only multivariate longitudinal studies, age-comparative experimental interventions, and a combination of the two will deliver us from the predicaments of the ABC triangle described by Salthouse. Mediation models of cross-sectional data represent age-related differences in target variables but fail to approximate time-dependent relations; thus, they do not elucidate the dimensions and dynamics of cognitive aging.     

Cross-sectional age variance extraction: what's change got to do with it?

In cross-sectional age variance extraction (CAVE), age, the indicator of a hypothesized developmental mechanism, and a developmental outcome are specified as independent, mediator, and target variables, respectively, to test hypotheses about behavioral development. We show that: (a) longitudinal change in a mediator variable accounting for substantial cross-sectional age-related variance in the target variable need not correlate with the target variable's longitudinal change; and, conversely, (b) longitudinal change in a mediator not sharing cross-sectional age-related variance with the target variable may nevertheless correlate highly with that variable's longitudinal change. We discourage use of CAVE for testing multivariate hypotheses about behavioral development.     

Modeling age and retest processes in longitudinal studies of cognitive abilities

Mixed effects models were used to examine the separate effects associated with age and retest on changes in various cognitive abilities. Individuals (N > 800) ranging in age from 40 to 70 years at the 1st measurement occasion were assessed with measures of memory, spatial abilities, and speed on 4 occasions. All cognitive abilities showed decline associated with increased age and improvement across the 4 measurement occasions. The age-related effects were similar across variables, but the practice effects were largest for memory and smallest for speed. When retest effects were not included in the models, the age-related effects were underestimated, with the magnitude of bias depending on the size of the ignored retest effects. It is suggested that both age and retest should be modeled simultaneously when analyzing longitudinal data because part of the change across occasions may be attributable to practice or reactive effects.     

On the confounds among retest gains and age-cohort differences in the estimation of within-person change in longitudinal studies: a simulation study

Although longitudinal designs are the only way in which age changes can be directly observed, a recurrent criticism involves to what extent retest effects may downwardly bias estimates of true age-related cognitive change. Considerable attention has been given to the problem of retest effects within mixed effects models that include separate parameters for longitudinal change over time (usually specified as a function of age) and for the impact of retest (specified as a function of number of exposures). Because time (i.e., intervals between assessment) and number of exposures are highly correlated (and are perfectly correlated in equal interval designs) in most longitudinal studies, the separation of effects of within-person change from effects of retest gains is only possible given certain assumptions (e.g., age convergence). To the extent that cross-sectional and longitudinal effects of age differ, obtained estimates of aging and retest may not be informative. The current simulation study investigated the recovery of within-person change (i.e., aging) and retest effects from repeated cognitive testing as a function of number of waves, age range at baseline, and size and direction of age-cohort differences on the intercept and age slope in age-based models of change. Significant bias and Type I error rates in the estimated effects of retest were observed when these convergence assumptions were not met. These simulation results suggest that retest effects may not be distinguishable from effects of aging-related change and age-cohort differences in typical long-term traditional longitudinal designs.     

Personality and aging: a study of the MMPI-2 among older men

We examined whether separate norms for older men are necessary for the revised Minnesota Multiphasic Personality Inventory (MMPI-2). Scores from 1,459 men in the Normative Aging Study (NAS) (age: M = 61.27, SD = 8.37) were contrasted with those from 1,138 men from the MMPI Restandardization Study (age: M = 41.71, SD = 15.32). Results showed that scores on the MMPI-2 validity, clinical, and content scales for the NAS men were highly similar to those from the MMPI-2 Restandardization sample. There were also few differences between the two groups at the item level. Within-sample analyses revealed some differences between age groups. However, the magnitudes of these differences were small and may represent the single or combined effects of cohort factors and age-related changes in physical health status rather than age-related changes in psychopathology per se. We concluded that special, age-related norms for the MMPI-2 are not needed for older men.