Cognitive Functioning and the Quality of Survey Responses: An Individual Participant Data Meta-Analysis of 10 Epidemiological Studies of Aging.

OBJECTIVES: Self-reported survey data are essential for monitoring the health and well-being of the population as it ages. For studies of aging to provide precise and unbiased results, it is necessary that the self-reported information meets high psychometric standards. In this study, we examined whether the quality of survey responses in panel studies of aging depends on respondents' cognitive abilities. METHODS: Over 17 million survey responses from 157,844 participants aged 50 years and older in 10 epidemiological studies of aging were analyzed. We derived 6 common statistical indicators of response quality from each participant's data and estimated the correlations with participants' cognitive test scores at each study wave. Effect sizes (correlations) were synthesized across studies, cognitive tests, and waves using individual participant data meta-analysis methods. RESULTS: Respondents with lower cognitive scores showed significantly more missing item responses (overall effect size ρ^ = -0.144), random measurement error (ρ^ = -0.192), Guttman errors (ρ^ = -0.233), multivariate outliers (ρ^ = -0.254), and acquiescent responses (ρ^ = -0.078); the overall effect for extreme responses (ρ^ = -0.045) was not significant. Effect sizes were consistent across studies, modes of survey administsration, and different cognitive functioning domains, although some cognitive domain specificity was also observed. DISCUSSION: Lower-quality responses among respondents with lower cognitive abilities add random and systematic errors to survey measures, reducing the reliability, validity, and reproducibility of survey study results in aging research.

Attrition from longitudinal ageing studies and performance across domains of cognitive functioning: an individual participant data meta-analysis.

OBJECTIVES: This paper examined the magnitude of differences in performance across domains of cognitive functioning between participants who attrited from studies and those who did not, using data from longitudinal ageing studies where multiple cognitive tests were administered. DESIGN: Individual participant data meta-analysis. PARTICIPANTS: Data are from 10 epidemiological longitudinal studies on ageing (total n=209 518) from several Western countries (UK, USA, Mexico, etc). Each study had multiple waves of data (range of 2-17 waves), with multiple cognitive tests administered at each wave (range of 4-17 tests). Only waves with cognitive tests and information on participant dropout at the immediate next wave for adults aged 50 years or older were used in the meta-analysis. MEASURES: For each pair of consecutive study waves, we compared the difference in cognitive scores (Cohen's d) between participants who dropped out at the next study wave and those who remained. Note that our operationalisation of dropout was inclusive of all causes (eg, mortality). The proportion of participant dropout at each wave was also computed. RESULTS: The average proportion of dropouts between consecutive study waves was 0.26 (0.18 to 0.34). People who attrited were found to have significantly lower levels of cognitive functioning in all domains (at the wave 2-3 years before attrition) compared with those who did not attrit, with small-to-medium effect sizes (overall d=0.37 (0.30 to 0.43)). CONCLUSIONS: Older adults who attrited from longitudinal ageing studies had lower cognitive functioning (assessed at the timepoint before attrition) across all domains as compared with individuals who remained. Cognitive functioning differences may contribute to selection bias in longitudinal ageing studies, impeding accurate conclusions in developmental research. In addition, examining the functional capabilities of attriters may be valuable for determining whether attriters experience functional limitations requiring healthcare attention.

Neighborhood Social Environment and Self-Perceptions of Aging.

Background and Objectives: Self-perceptions of aging (SPA) are associated with health and well-being later in life. Although prior studies have identified individual-level predictors of SPA, the role of neighborhood social context in SPA remains largely unexplored. A neighborhood social environment may act as a critical avenue for older adults to remain healthy and socially active, contributing to their evaluations of how they grow old. The present study aims to fill the previous research gap by examining the relationship between neighborhood social environment and SPA, and how age may moderate this relationship. This study is guided by Bronfenbrenner's Ecology of Human Development theory and Lawton's Ecological Model of Aging, positing that an individual's aging experience is deeply rooted in their residential environment. Research Design and Methods: Our sample includes 11,145 adults aged 50+ from the 2014 and 2016 waves of the Health and Retirement Study. We included 4 social and economic aspects of neighborhoods: (1) neighborhood poverty; (2) percentage of older adults; (3) perceived social cohesion; and (4) perceived disorder. Results: Multilevel linear regression models showed that respondents in neighborhoods with higher percentages of the older population and with perceptions of high neighborhood disorder reported more negative SPA. Those who perceived their neighborhoods as more socially cohesive reported more positive SPA. Controlling for individual socioeconomic and health status, only neighborhood social cohesion remained significant. We also found significant interaction effects between neighborhood social cohesion and age: The effects of neighborhood cohesion on SPA were stronger in middle age than in old age. Discussion and Implications: Our findings provide insights into how neighborhood social context is associated with SPA, suggesting that a socially cohesive neighborhood may be important to promote more favorable perceptions of aging, particularly for middle-aged residents.

Using Item Response Times in Online Questionnaires to Detect Mild Cognitive Impairment.

OBJECTIVES: With the increase in web-based data collection, response times (RTs) for survey items have become a readily available byproduct in most online studies. We examined whether RTs in online questionnaires can prospectively discriminate between cognitively normal respondents and those with cognitive impairment, no dementia (CIND). METHOD: Participants were 943 members of a nationally representative internet panel, aged 50 and older. We analyzed RTs that were passively recorded as paradata for 37 surveys (1,053 items) administered online over 6.5 years. A multilevel location-scale model derived 3 RT parameters for each survey: (1) a respondent's average RT and 2 components of intraindividual RT variability addressing (2) systematic RT adjustments and (3) unsystematic RT fluctuations. CIND status was determined at the end of the 6.5-year period. RESULTS: All 3 RT parameters were significantly associated with CIND, with a combined predictive accuracy of area under the receiver-operating characteristic curve = 0.74. Slower average RTs, smaller systematic RT adjustments, and greater unsystematic RT fluctuations prospectively predicted a greater likelihood of CIND over periods of up to 6.5, 4.5, and 1.5 years, respectively. DISCUSSION: RTs for survey items are a potential early indicator of CIND, which may enhance analyses of predictors, correlates, and consequences of cognitive impairment in online survey research.

Quality of Survey Responses at Older Ages Predicts Cognitive Decline and Mortality Risk.

Background and Objectives: It is widely recognized that survey satisficing, inattentive, or careless responding in questionnaires reduce the quality of self-report data. In this study, we propose that such low-quality responding (LQR) can carry substantive meaning at older ages. Completing questionnaires is a cognitively demanding task and LQR among older adults may reflect early signals of cognitive deficits and pathological aging. We hypothesized that older people displaying greater LQR would show faster cognitive decline and greater mortality risk. Research Design and Methods: We analyzed data from 9, 288 adults 65 years or older in the Health and Retirement Study. Indicators of LQR were derived from participants' response patterns in 102 psychosocial questionnaire items administered in 2006-2008. Latent growth models examined whether LQR predicted initial status and change in cognitive functioning, assessed with the modified Telephone Interview for Cognitive Status, over the subsequent 10 years. Discrete-time survival models examined whether LQR was associated with mortality risk over the 10 years. We also examined evidence for indirect (mediated) effects in which LQR predicts mortality via cognitive trajectories. Results: After adjusting for age, gender, race, marital status, education, health conditions, smoking status, physical activity, and depressive symptoms, greater LQR was cross-sectionally associated with poorer cognitive functioning, and prospectively associated with faster cognitive decline over the follow-up period. Furthermore, greater LQR was associated with increased mortality risk during follow-up, and this effect was partially accounted for by the associations between LQR and cognitive functioning. Discussion and Implications: Self-report questionnaires are not formally designed as cognitive tasks, but this study shows that LQR indicators derived from self-report measures provide objective, performance-based information about individuals' cognitive functioning and survival. Self-report surveys are ubiquitous in social science, and indicators of LQR may be of broad relevance as predictors of cognitive and health trajectories in older people.

Personality predictors of cognitive dispersion: A coordinated analysis of data from seven international studies of older adults.

OBJECTIVES: Dispersion in cognitive test performance within a single testing session is proposed as an early marker of poor brain health. Existing research, however, has not investigated factors that may explain individual differences in cognitive dispersion. We investigate the extent to which the Big Five personality traits are associated with cognitive dispersion in older adulthood. METHOD: To promote transparency and reliability, we applied preregistration and conceptual replication via coordinated analysis. Drawing data from seven longitudinal studies of aging (Ntotal = 33,581; Mage range = 56.4-71.2), cognitive dispersion scores were derived from cognitive test results. Independent linear regression models were fit in each study to examine personality traits as predictors of dispersion scores, adjusting for mean cognitive performance and sociodemographics (age, sex, education). Results from individual studies were synthesized using random effects meta-analyses. RESULTS: Synthesized results revealed that openness was positively associated with cognitive dispersion, 0.028, 95% CI [0.003, 0.054]. There was minimal evidence for associations between cognitive dispersion and the other personality traits in independent analyses or meta-analyses. Mean cognitive scores were negatively associated with cognitive dispersion across the majority of studies, while sociodemographic variables were not consistently associated with cognitive dispersion. CONCLUSION: Higher levels of openness were associated with greater cognitive dispersion across seven independent samples, indicating that individuals higher in openness had more dispersion across cognitive tests. Further research is needed to investigate mechanisms that may help to explain the link between openness and cognitive dispersion, as well as to identify additional individual factors, beyond personality traits, that may be associated with cognitive dispersion. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Subtle mistakes in self-report surveys predict future transition to dementia.

INTRODUCTION: We investigate whether indices of subtle reporting mistakes derived from responses in self-report surveys are associated with dementia risk. METHODS: We examined 13,831 participants without dementia from the prospective, population-based Health and Retirement Study (mean age 69 ± 10 years, 59% women). Participants' response patterns in 21 questionnaires were analyzed to identify implausible responses (multivariate outliers), incompatible responses (Guttman errors), acquiescent responses, random errors, and the proportion of skipped questions. Subsequent incident dementia was determined over up to 10 years of follow-up. RESULTS: During follow-up, 2074 participants developed dementia and 3717 died. Each of the survey response indices was associated with future dementia risk controlling for confounders and accounting for death as a competing risk. Stronger associations were evident for participants who were younger and cognitively normal at baseline. DISCUSSION: Mistakes in the completion of self-report surveys in longitudinal studies may be early indicators of dementia among middle-aged and older adults.

Information and Communication Technology Use in Older Adults: A Unidirectional or Bi-directional Association with Cognitive Function?

Previous research on older adults' information and communication technology (ICT) use has shown that cognitive function is linked with ICT use; however, the direction of influence has been yet to be determined. The current study examined the temporal sequence of ICT use and cognitive performance. Using three waves (2013, 2015, and 2017) from the National Health and Aging Trends Study, a total of 3,904 community-dwelling older adults aged 65 and above were selected for the analysis. Two cognitive domains were considered: episodic memory and executive function. Reciprocal 4-year lagged associations between ICT use and each cognitive domain were examined, controlling for covariates (age, gender, education, race/ethnicity, and depression). Greater use of ICT was significantly associated with memory performance, B (SE) = .19 (.01), p < .001, and executive function, B (SE) = .26 (.01), p < .001, in following years. Reciprocally, episodic memory predicted ICT use, B (SE) = .02 (.01), p < .001, 2 years later. However, the cross-lagged effect of executive functioning on ICT use was not significant, B (SE) = .00 (.01), p = .14. These results suggest the direction of the association between ICT use and cognitive performance might vary depending on the cognitive domain.

Is Healthy Neuroticism Associated with Longevity? A Coordinated Integrative Data Analysis.

Individual differences in the Big Five personality traits have emerged as predictors of health and longevity. Although there are robust protective effects for higher levels of conscientiousness, results are mixed for other personality traits. In particular, higher levels of neuroticism have significantly predicted an increased risk of mortality, no-risk at all, and even a reduced risk of dying. The current study hypothesizes that one potential reason for the discrepancy in these findings for neuroticism is that interactions among neuroticism and other key personality traits have largely been ignored. Thus, in the current study we focus on testing whether the personality traits neuroticism and conscientiousness interact to predict mortality. Specifically, we borrow from recent evidence of "healthy neuroticism" to explore whether higher levels of neuroticism are only a risk factor for increased mortality risk when conscientiousness levels are low. We conducted a pre-registered integrative data analysis using 12 different cohort studies (total N = 44,702). Although a consistent pattern emerged of higher levels of conscientiousness predicting a reduced hazard of dying, neuroticism did not show a consistent pattern of prediction. Moreover, no study provided statistical evidence of a neuroticism by conscientiousness interaction. The current findings do not support the idea that the combination of high conscientiousness and high neuroticism can be protective for longevity. Future work is needed to explore different protective factors that may buffer the negative effects of higher levels of neuroticism on health, as well as other behaviors and outcomes that may support the construct of healthy neuroticism.

Is Healthy Neuroticism Associated with Health Behaviors? A Coordinated Integrative Data Analysis.

Current literature suggests that neuroticism is positively associated with maladaptive life choices, likelihood of disease, and mortality. However, recent research has identified circumstances under which neuroticism is associated with positive outcomes. The current project examined whether "healthy neuroticism", defined as the interaction of neuroticism and conscientiousness, was associated with the following health behaviors: smoking, alcohol consumption, and physical activity. Using a pre-registered multi-study coordinated integrative data analysis (IDA) approach, we investigated whether "healthy neuroticism" predicted the odds of engaging in each of the aforementioned activities. Each study estimated identical models, using the same covariates and data transformations, enabling optimal comparability of results. These results were then meta-analyzed in order to estimate an average (N-weighted) effect and to ascertain the extent of heterogeneity in the effects. Overall, these results suggest that neuroticism alone was not related to health behaviors, while individuals higher in conscientiousness were less likely to be smokers or drinkers, and more likely to engage in physical activity. In terms of the healthy neuroticism interaction of neuroticism and conscientiousness, significant interactions for smoking and physical activity suggest that the association between neuroticism and health behaviors was smaller among those high in conscientiousness. These findings lend credence to the idea that healthy neuroticism may be linked to certain health behaviors and that these effects are generalizable across several heterogeneous samples.

Is Healthy Neuroticism Associated with Chronic Conditions? A Coordinated Integrative Data Analysis.

Early investigations of the neuroticism by conscientiousness interaction with regards to health have been promising, but to date, there have been no systematic investigations of this interaction that account for the various personality measurement instruments, varying populations, or aspects of health. The current study - the second of three - uses a coordinated analysis approach to test the impact of the neuroticism by conscientiousness interaction on the prevalence and incidence of chronic conditions. Using 15 pre-existing longitudinal studies (N > 49,375), we found that conscientiousness did not moderate the relationship between neuroticism and having hypertension (OR = 1.00,95%CI[0.98,1.02]), diabetes (OR = 1.02[0.99,1.04]), or heart disease (OR = 0.99[0.97,1.01]). Similarly, we found that conscientiousness did not moderate the prospective relationship between neuroticism and onset of hypertension (OR = 0.98,[0.95,1.01]), diabetes (OR = 0.99[0.94,1.05]), or heart disease (OR = 0.98[0.94,1.03]). Heterogeneity of effect sizes was largely nonsignificant, with one exception, indicating that the effects are consistent between datasets. Overall, we conclude that there is no evidence that healthy neuroticism, operationalized as the conscientiousness by neuroticism interaction, buffers against chronic conditions.

The bidirectional relationship between physical health and memory.

Individuals typically experience changes in physical health and cognitive ability across the life span. Although these constructs dynamically relate to one another, the temporal ordering of dynamic changes in physical health and cognitive ability is not well-established. Therefore, we examined the temporal ordering of the dynamic, bidirectional relationship between physical health and memory across ages 50-87 with Bivariate Dual Change Score Models (BDCSM). Employing a model-comparison approach, we tested whether inclusion of specific directional coupling parameters resulted in a meaningful improvement in model fit, controlling for education, gender, and race. The current sample included 9,103 individuals who participated in Waves 4-11 (1998-2012) of the Health and Retirement Study. Results indicated that both memory and physical health declined across ages 50-87. Furthermore, level of memory at a given time point was positively associated with subsequent change in physical health, meaning higher memory was linked to less decline in physical health by the subsequent time point. The opposite effect, namely physical health predicting memory, was much weaker. Age differences were also evident in the bidirectional coupling model, indicating that old-old individuals (i.e., ages 75-87) exhibited a much stronger coupling effect from memory to change in physical health than younger individuals (i.e., ages 50-74). In conclusion, memory buffers decline in physical health across mid-to-later life, and this effect is especially strong at older ages. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The Association Between Spousal Education and Cognitive Ability Among Older Mexican Adults.

OBJECTIVES: Education and cognition are closely associated, yet the role of spousal education is not well understood. We estimate the independent effects of own and spousal education on cognitive ability in late-life in Mexico, a developing country experiencing rapid aging. METHOD: We analyzed 4,017 married dyads (age 50+) from the 2012 Mexican Health and Aging Study. Cognitive ability for married adults was a factor score from a single factor model. Using seemingly unrelated regression, we test whether spousal education influences older adults' cognitive ability, whether associations are explained by couple-level socioeconomic position, health and health behaviors, and social support, and whether associations differed by gender. RESULTS: Education and cognitive ability were correlated within couples. Higher spousal education was associated with better cognitive ability. Associations between spousal education and cognitive ability were independent of own education, did not differ by gender, and remained significant even after adjustment for couple-level socioeconomic position, health and health behaviors, and perceived social support. DISCUSSION: In addition to own education, spousal education was associated with better cognitive ability, even at relatively low levels of education. We discuss the possibility that spousal education may improve cognition via transmission of knowledge and mutually reinforcing cognitively stimulating environments.

Mobile Apps for Caregivers of Older Adults: Quantitative Content Analysis.

BACKGROUND: Informal caregivers of older adults provide critical support for their loved ones but are subject to negative health outcomes because of burden and stress. Interventions to provide information and resources as well as social and emotional support reduce burden. Mobile apps featuring access to information, assistance with scheduling, and other features can automate support functions inexpensively and conveniently and reach a greater proportion of caregivers than otherwise possible. OBJECTIVE: The aim of this study was to identify mobile apps geared towards caregivers of older adults, catalog features, and suggest best practices for adoption based on empirical findings of beneficial interventions in the caregiving literature. METHODS: Search for apps focused on ones catered for caregivers of older adults in Google Play and iTunes, compiling their features, and identifying features reflecting categories of support identified in successful intervention studies to negative caregiver outcomes. Intervention research indicates that provision of information and resources, assistance in practical problem solving, coordinating care among multiple caregivers, and emotional support reduce caregiver burden. RESULTS: Despite approximately over 200,000 mobile health-related apps, the availability of mobile apps for caregivers is relatively sparse (n=44 apps) as of October 2017. Apps generally addressed specific categories of support, including information and resources, family communication, and caregiver-recipient interactions. Few apps were comprehensive. Only 8 out of 44 (18%) had features that addressed three or more categories. Few apps provided specific stress reduction exercises for caregivers, which is important for reducing burden. CONCLUSIONS: Mobile apps have the potential to provide resources, just--in--time information for problem-solving, and stress reduction strategies for caregivers. Many apps offer functions that have been shown to reduce burden and improve health outcomes in caregivers, but few provide emotional support. Using an evidence--based practice approach, mobile apps for caregivers can provide multiple beneficial support functions. Apps can serve a much larger proportion of this highly underserved population in their mobile form than more traditional means, improving their health and quality of life.

Personality Predicts Mortality Risk: An Integrative Data Analysis of 15 International Longitudinal Studies.

This study examined the Big Five personality traits as predictors of mortality risk, and smoking as a mediator of that association. Replication was built into the fabric of our design: we used a Coordinated Analysis with 15 international datasets, representing 44,094 participants. We found that high neuroticism and low conscientiousness, extraversion, and agreeableness were consistent predictors of mortality across studies. Smoking had a small mediating effect for neuroticism. Country and baseline age explained variation in effects: studies with older baseline age showed a pattern of protective effects (HR<1.00) for openness, and U.S. studies showed a pattern of protective effects for extraversion. This study demonstrated coordinated analysis as a powerful approach to enhance replicability and reproducibility, especially for aging-related longitudinal research.

Cognitive activity mediates the association between social activity and cognitive performance: A longitudinal study.

Social activity is 1 aspect of an active lifestyle and some evidence indicates it is related to preserved cognitive function in older adulthood. However, the potential mechanisms underlying this association remain unclear. We investigate 4 potential mediational pathways through which social activity may relate to cognitive performance. A multilevel structural equation modeling approach to mediation was used to investigate whether cognitive activity, physical activity, depressive symptoms, and vascular health conditions mediate the association between social activity and cognitive function in older adults. Using data from the Victoria Longitudinal Study, we tested 4 cognitive outcomes: fluency, episodic memory, reasoning, and vocabulary. Three important findings emerged. First, the association between social activity and all 4 domains of cognitive function was significantly mediated by cognitive activity at the within-person level. Second, we observed a significant indirect effect of social activity on all domains of cognitive function through cognitive activity at the between-person level. Third, we found a within-person indirect relationship of social activity with episodic memory performance through physical activity. For these older adults, engagement in social activities was related to participation in everyday cognitive activities and in turn to better cognitive performance. This pattern is consistent with the interpretation that a lifestyle of social engagement may benefit cognitive performance by providing opportunities or motivation to participate in supportive cognitively stimulating activities. (PsycINFO Database Record

Context-Dependent Learning in People With Parkinson's Disease.

Context-dependent learning is a phenomenon in which people demonstrate superior performance in the context in which they originally learned a skill but perform less well in a novel context. This study investigated context-dependent learning in people with Parkinson's disease (PD) and age-matched nondisabled adults. All participants practiced 3 finger sequences, each embedded within a unique context (colors and locations on a computer screen). One day after practice, the participants were tested either under the sequence-context associations remained the same as during practice, or the sequence-context associations were changed (SWITCH). Compared with nondisabled adults, people with PD demonstrated significantly greater decrement in performance (especially movement time) under the SWITCH condition, suggesting that individuals with PD are more context dependent than nondisabled adults.

Evaluating the relationship between change in performance on training tasks and on untrained outcomes.

Training interventions for older adults are designed to remediate performance on trained tasks and to generalize, or transfer, to untrained tasks. Evidence for transfer is typically based on the trained group showing greater improvement than controls on untrained tasks, or on a correlation between gains in training and in transfer tasks. However, this ignores potential correlational relationships between trained and untrained tasks that exist before training. By accounting for crossed (trained and untrained) and lagged (pre-training and post-training) and cross-lagged relationships between trained and untrained scores in structural equation models, the training-transfer gain relationship can be independently estimated. Transfer is confirmed if only the trained but not control participants' gain correlation is significant. Modeling data from the Improvement in Memory with Plasticity-based Adaptive Cognitive Training (IMPACT) study (Smith et al., 2009), transfer from speeded auditory discrimination and syllable span to list and text memory and to working memory was demonstrated in 487 adults aged 65-93. Evaluation of age, sex, and education on pretest scores and on change did not alter this. The overlap of the training with transfer measures was also investigated to evaluate the hypothesis that performance gains in a non-verbal speeded auditory discrimination task may be associated with gains on fewer tasks than gains in a verbal working memory task. Gains in speeded processing were associated with gains on one list memory measure. Syllable span gains were associated with improvement in difficult list recall, story recall, and working memory factor scores. Findings confirmed that more overlap with task demands was associated with gains to more of the tasks assessed, suggesting that transfer effects are related to task overlap in multimodal training.

How Interventions Might Improve Cognition in Healthy Older Adults.

Many of the cognitive declines in healthy aging are moderated by experience, suggesting that interventions may be beneficial. Goals for aging outcomes include improving performance on untrained tasks, remediating observed cognitive declines, and ensuring preservation of functional ability. This selective review evaluates current progress towards these goals. Most research focuses on untrained tasks. Interventions associated with this outcome include games and exercises practicing specific cognitive skills, as well as aerobic exercise, and modestly benefit a relatively narrow range of cognitive tasks. Few studies have directly tested improvements in tasks on which individuals have been shown to experience longitudinal decline, so this goal has not been realized, though remediation can be examined rather easily. Little work has been done to develop psychometrically strong functional outcomes that could be used to test preservation of independence in everyday activities. Virtual reality approaches to functional assessment show promise for achieving the third goal.

Dynamic associations of change in physical activity and change in cognitive function: coordinated analyses of four longitudinal studies.

The present study used a coordinated analyses approach to examine the association of physical activity and cognitive change in four longitudinal studies. A series of multilevel growth models with physical activity included both as a fixed (between-person) and time-varying (within-person) predictor of four domains of cognitive function (reasoning, memory, fluency, and semantic knowledge) was used. Baseline physical activity predicted fluency, reasoning and memory in two studies. However, there was a consistent pattern of positive relationships between time-specific changes in physical activity and time-specific changes in cognition, controlling for expected linear trajectories over time, across all four studies. This pattern was most evident for the domains of reasoning and fluency.