Nonlinear blood pressure effects on cognition in old age: separating between-person and within-person associations

Midlife hypertension is associated with increased risk of cognitive impairment in later life. The association between blood pressure (BP) in older ages and cognition is less clear. In this study we provide estimates of between-person and within-person associations of BP and cognition in a population-based sample (N = 382) followed from age 70 across 12 occasions over 30 years. Between-person associations refer to how individual differences in BP relates to individual differences in cognition. Within-person associations refer to how individual and time specific changes in BP relate to variation in cognition. Hierarchical linear models were fitted to data from three cognitive measurements (verbal ability, spatial ability, and perceptual speed) while accounting for demographic and health-related covariates. We found consistent nonlinear between-person associations between diastolic BP (DBP) and cognition, such that both low (<75 mmHg) and high (>95 mmHg) pressure were associated with poorer cognition. Within-person decreases in systolic BP (SBP) and DBP were associated with decreases in perceptual speed. Notably, between-person and within-person estimates did not reveal similar associations, suggesting the need to separate the two effects in the analysis of associations between BP and cognition in old age.     

Decomposing the within-person and between-person sources of variation in physical activity-cognition associations for low-active older adults

Abstract

Objectives: To examine within-person and between-person sources of variation in the relationship between physical activity and cognition in older adults participating in a walking program. To explore whether demographic, health and fitness variables, and their interactions with activity, are significant predictors of cognition.

Design: Brief longitudinal burst design.

Participants: 118 participants (91 females, mean age?=?72.81?+ 5.24 years).

Main Outcome Measures: Cognition, self-reported moderate-to-vigorous walking and self-reported moderate-to-vigorous physical activity were assessed at baseline and 6, 9, 12 and 16 weeks follow-up. Attendance at weekly walks was also recorded.

Results: Within-persons, changes in physical activity were related to select measures of executive functioning, with increased activity predictive of better cognition (three of four cognitive functions, p<.05). Between-persons, activity was also associated with cognition (two of four cognitive functions, p<.05). Younger age and higher education were related to better cognition. Interactions of demographic, health, and fitness variables with changes in within-person activity were generally non-significant.

Conclusion: The results highlight the importance of distinguishing within- from between-person effects in longitudinal analyses of the association between physical activity and cognition. This stringent within-person test of association underscores the potential value of simple physical activity interventions for improving cognitive function.     

Within-subject covariation between depression- and anxiety-related affect

Studies find a strong positive relationship between the affective components of anxiety and depression. However, most research thus far has examined the between-person correlations among these constructs, while ignoring how changes in these two types of affect covary over time within a person. Within-person correlations could differ meaningfully from how anxiety- and depression-related affect relate across individuals. Further, individuals may differ in terms of how highly these constructs covary over time. The current study aimed to (1) compare between- and within-person correlations between anxious and depressive affect, (2) examine lagged effects between anxious and depressive affect over time, (3) test whether individuals differ in their within-person correlations between these two types of affect, and (4) examine whether the mean level of affective intensity moderated these individual differences. These questions were explored using college undergraduates (N?=?50) who rated their depression- and anxiety- related affect six times a day for two weeks. A higher average correlation was observed between anxious and depressive affect in between-person compared to within-person analyses. Significant bidirectional lagged effects were observed between these constructs. Individuals with higher average levels of anxious affect experienced stronger within-person correlations between anxious and depressive affect.     

Sluggish Cognitive Tempo as a Transdiagnostic Link Between Adult ADHD and Internalizing Symptoms

Although absent from traditional diagnostic nosologies, Sluggish Cognitive Tempo (SCT) may have transdiagnostic utility given its robust associations with ADHD and internalizing symptoms as well as with cognitive impairments common to these conditions. Within-person variation in SCT symptoms may also serve to link ADHD, cognitive deficits, and internalizing psychopathology, however, few studies have utilized intensive longitudinal designs to probe within-person variation in SCT and its links to cognitive deficits and psychopathology. Ecological Momentary Assessment was used to measure between and within-person variance in SCT 4 times per day across 7 days (28 time-points) in 158 college students (approximately 51% with elevated ADHD and/or internalizing symptoms). Participants also completed ratings of current and childhood ADHD symptoms, cognitive function and internalizing psychopathology. Parameters derived from longitudinal multilevel models indexing between and within person variation in SCT were examined as mediators of the associations between (1) ADHD and internalizing symptoms and (2) self-reported cognitive functioning and internalizing symptoms. Results indicated that between-person differences in SCT, but not within-person variability, linked current and childhood ADHD and internalizing symptoms. Similarly, problems in time-management and organization influenced internalizing psychopathology via between-person differences in SCT. Results found that SCT may be a transdiagnostic link bridging mental health comorbidities, cognitive dysfunction, and internalizing psychopathology.

     

Psychometric Properties of the Beck Depression Inventory–II in Low-Income,African American Suicide Attempters

The construct of perfectionistic cognitions is defined as a state-like construct resulting from a perfectionistic self-schema and activated by specific situational demands. Only a few studies have investigated whether and how perfectionistic cognitions change across different situations and whether they reflect stable between-person differences or also within-person variations over time. We conducted 2 studies to investigate the variability and stability of 3 dimensions of perfectionistic cognitions while situational demands changed (Study 1) and on a daily level during a highly demanding period of time (Study 2). The results of both studies revealed that stable between-person differences accounted for the largest proportion of variance in the dimensions of perfectionistic cognitions and that these differences were validly associated with between-person differences in affect. The frequency of perfectionistic cognitions increased during students' first semester at university, and these average within-person changes were different for the 3 dimensions of perfectionistic cognitions (Study 1). In addition, there were between-person differences in the within-person changes that were validly associated with concurrent changes in closely related constructs (unpleasant mood and tense arousal). Within-person variations in perfectionistic cognitions were also validly associated with variations in unpleasant mood and tense arousal from day to day (Study 2).     

A daily process analysis of physical activity,sedentary behavior,and perceived cognitive abilities

ObjectivesThis study evaluated the role of both physical activity and sedentary behavior in daily perceptions of cognitive abilities and whether these relations exist within-person, between-person, or both.DesignNon-experimental, intensive longitudinal research using ecological momentary assessments.MethodCollege students wore accelerometers and provided end-of-day reports on physical activity, sedentary behavior, and perceived cognitive abilities for 14 days.ResultsAcross self-reports and objective measures of behavior, daily deviations in physical activity were positively associated with perceived cognitive abilities. Daily deviations in self-reported, but not objectively-assessed, sedentary behavior also were negatively associated with perceived cognitive abilities. Contrary to previous research, overall levels of physical activity and sedentary behaviors were not associated with perceived cognitive abilities.ConclusionsThese findings indicate that physical activity has a within- rather than between-person association with perceived cognitive abilities although between-person associations effects may require longer monitoring periods to manifest. Further research is needed to establish the direction of causality and resolve whether the nature (rather than quantity) of sedentary activities influences cognition.     

Within-person covariation of agentic and communal perceptions: Implications for interpersonal theory and assessment

Interpersonal theory identifies agency and communion as uncorrelated (orthogonal) dimensions, largely evidenced by research examining between-person analyses of single-occasion measures. However, longitudinal studies of interpersonal behavior demonstrated the within-person association of agency and communion is not orthogonal for many individuals, and between-person differences in these associations relate to adjustment. We applied a similar approach to investigate the association of interpersonal perceptions. 184 university students completed a 7-day event-contingent study of their interpersonal experiences. Using multilevel regression models, we demonstrated that agentic and communal perceptions were positively associated, and the strength of this within-person association was moderated by between-person scores of dependency and narcissism. We discuss the benefits of incorporating within-person interpersonal associations (termed interpersonal covariation) into interpersonal theory and assessment.     

Aggregating to the between-person level in idiographic research designs: Personal goal research as an example of the need to distinguish between reliability and homogeneity

In several areas of personality research (e.g., personal networks, interpersonal behaviour, academic effort), the empirical data represent a multilevel structure, in which within-person variables are nested within individuals. Both within-person variation and between-person differences can be related to outcome variables (e.g., emotions, life satisfaction). One major precondition for aggregating within-person data to the between-person level is sufficient reliability of the aggregated data, a point that has received scant attention in previous research. Drawing on the example of personal goal research, we recommend that the two major forms of the intraclass correlation coefficient—the ICC(1) and the ICC(2)—be applied to within-person data in idiographic research designs. These indices allow the homogeneity and reliability of within-person data to be determined separately. Their application is illustrated using data from a study with 4,565 young adults.     

Longitudinal Analysis of Associations between 3-D Mental Rotation and Mathematics Reasoning Skills during Middle School: Across and within Genders

ABSTRACT

The development of math reasoning and 3-d mental rotation skills are intertwined. However, it is currently not understood how these cognitive processes develop and interact longitudinally at the within-person level – either within or across genders. In this study, 553 students (52% girls) were assessed from fifth to seventh grades on 3-d mental rotation spatial skills (assessed each fall) and numerical and algebraic math reasoning skills (assessed each spring). Boys outperformed girls on mental rotation tests across all three grades, and on fifth and seventh grade math reasoning tests. Consistent with the literature on between-person comparisons, there was a positive correlation between mental rotation and math reasoning skills in the full sample and for both genders. A random intercept cross-lagged panel model was used to control for these confounding group-level differences in order to isolate within-person associations between earlier and later performance. Initially in fifth grade, math reasoning predicted subsequent sixth grade mental rotation skills. By seventh grade, more advanced mental rotation skills were associated with subsequent math reasoning skills while math reasoning skills were no longer predictive of mental rotation skills. An examination of gender differences revealed that this pattern was driven by boys while girls experienced less within-person change. These findings suggest that boys may initially rely in part on their math reasoning skills to solve 3-d mental rotation tasks. However, as their 3-d mental rotation skills mature, they begin to primarily depend upon these developing spatial skills to solve math reasoning problems rather than the reverse.     

Modeling Intraindividual Cognitive Change in Aging Adults: Results from the Einstein Aging Studies

This paper reviews research from the longitudinal Einstein Aging Studies (EAS) that has focused on modeling intraindividual cognitive change in aging adults. We describe how to separate models of intraindividual change at the within-person level from models of individual differences in change at the between-person level. We illustrate this distinction by analyzing new data from the EAS to test the speed hypothesis at the intraindividual level of analyses. The present findings replicate those of Sliwinski and Buschke (1999) by showing that within-person changes in speed predict within-person changes in cognition, but that speed does not substantially attenuate estimates of within-person cognitive decline. We conclude that correct measurement and explanatory modeling of intraindividual change should be the primary focus of longitudinal aging research, and that the more common practice of modeling individual differences in change should be a secondary focus.     

A dynamic view of coach transformational leadership: How leadership perceptions relate to task cohesion and team potency

We examined whether athletes’ perceptions of coach transformational leadership across time related to task cohesion and team potency beliefs. Across multiple time points, we collected 384 observations (M = 5.41 observations per athlete) from competitive youth athletes via a mobile application designed to examine team dynamics. Multilevel structural equation modelling revealed intraindividual variation in athletes’ evaluations of coach transformational leadership across time. Further, we observed robust support for a positive relation between perceptions of coach transformational leadership and task cohesion over time at both the between- and within-person levels. The relation between coach transformational leadership and team potency was significant at the between-person level, however, we did not find support for this relation at the within-person level. These results provide insight into how the ebb and flow of coach transformational leadership over time connects to team cohesion, highlighting the need for more intensive longitudinal designs that capture the dynamic nature of leadership.     

A longitudinal multilevel model analysis of the within-person and between-person effect of effortful engagement and academic self-efficacy on academic performance

Using data from an accelerated longitudinal study, we examined the within-person and between-person effect of effortful engagement and academic self-efficacy on academic performance across students (N = 135) in elementary school. Teachers assessed participants' effortful engagement and participants rated their academic self-efficacy once per year for 3 years. Academic performance was assessed through standardized test scores in reading and math. Multilevel models indicated that within-person change in Effortful Engagement and Academic Self-Efficacy scores significantly predicted concomitant within-person change in reading test scores, B = 2.71, p = .043, Pseudo-R² = .02 and B = 4.72, p = .005, Pseudo-R² = .04, respectively. Participants with higher between-person levels of Effortful Engagement had higher initial reading test scores, B = 10.03, p = .001, Pseudo-R² = .09, and math test scores, B = 11.20, p < .001, Pseudo-R² = .15, whereas participants with higher between-person levels of Academic Self-Efficacy showed a faster rate of increase in math test scores across elementary school, B = 10.21, p = .036, Pseudo-R² = .25. At the between-person level, Effortful Engagement mediated the association between Academic Self-Efficacy and both reading and math test scores, although no support was found for mediation at the within-person level. Collectively, results suggest that trait-level psychological factors can vary meaningfully within school-aged children and that both within-person change and between-person individual differences in these traits have important consequences for academic performance.     

Dynamics in Self-Regulation: Plan Execution Self-Efficacy and Mastery of Action Plans

This study investigated whether an individual's plan execution self-efficacy precedes mastery of the respective action plan or vice versa. Study participants were 122 cardiac rehabilitation patients. Plan execution self-efficacy and mastery of a personal action plan on physical activity were assessed each week for 6 weeks after discharge from rehabilitation. Physical exercise was assessed 2 months after discharge. Multilevel cross-lagged panel analyses resulted in a positive effect of mastery on subsequent self-efficacy, whereas self-efficacy did not predict subsequent mastery at the within-person level. At the between-person level, however, self-efficacy predicted following physical exercise. Thus, the predictive power of self-efficacy was developed in relation to mastery of personal action plans over time. Implications for behavior change interventions are discussed.     

Aggressive and Prosocial Behavior: Community Violence, Cognitive, and Behavioral Predictors Among Urban African American Youth

We use longitudinal multilevel modeling to test how exposure to community violence and cognitive and behavioral factors contribute to the development of aggressive and prosocial behaviors. Specifically, we examine predictors of self-, peer-, and teacher-reported aggressive and prosocial behavior among 266 urban, African American early adolescents. We examine lagged, within-person, between-person, and protective effects across 2 years. In general, results suggest that higher levels of violence exposure and aggressive beliefs are associated with more aggressive and less prosocial peer-reported behavior, whereas greater self-efficacy to resolve conflict peacefully is associated with less aggression across reporters and more teacher-reported prosocial behavior. Greater knowledge and violence prevention skills are associated with fewer aggressive and more prosocial teacher-reported behaviors. Results also suggest that greater self-efficacy and lower impulsivity have protective effects for youth reporting higher levels of exposure to community violence, in terms of teacher-reported aggressive behavior and peer-reported prosocial behavior. Differences among reporters and models are discussed, as well as implications for intervention.     

RETEST EFFECTS IN OPERATIONAL SELECTION SETTINGS: DEVELOPMENT AND TEST OF A FRAMEWORK

This study proposes a framework for examining the effects of retaking tests in operational selection settings. A central feature of this framework is the distinction between within-person and between-person retest effects. This framework is used to develop hypotheses about retest effects for exemplars of 3 types of tests (knowledge tests, cognitive ability tests, and situational judgment tests) and to test these hypotheses in a high stakes selection setting (admission to medical studies in Belgium). Analyses of within-person retest effects showed that mean scores of repeat test takers were one-third of a standard deviation higher for the knowledge test and situational judgment test and one-half of a standard deviation higher for the cognitive ability test. The validity coefficients for the knowledge test differed significantly depending on whether examinees' test scores on the first versus second administration were used, with the latter being more valid. Analyses of between-person retest effects on the prediction of academic performance showed that the same test score led to higher levels of performance for those passing on the first attempt than for those passing on the second attempt. The implications of these results are discussed in light of extant retesting practice.     

A Longitudinal Investigation of Perceived Control and Cognitive Performance in Young,Midlife and Older Adults

ABSTRACT

Longitudinal associations between generalized control beliefs (one's perceived capacity to influence events) and cognitive test performance were examined in a population-based sample of young, midlife and older adults. Participants provided measures of perceived control, self-assessed health, education and depression and anxiety symptoms, and completed cognitive tests at two assessments, 4 years apart. For each age group, baseline (between-person) control was positively related to performance on tests of memory (immediate recall and digits backwards), speed (Symbol Digit Modalities Test and choice reaction time) and verbal intelligence (Spot-the-Word). Interaction effects indicated stronger associations of between-person control beliefs with indices of speed for the older age group relative to the younger groups. Within-person changes in control were not significantly associated with changes in cognitive test performance over the study interval. Implications of the findings for self-efficacy based interventions designed to promote cognitive functioning are discussed.     

A Resource-Based Perspective on Organizational Citizenship and Counterproductive Work Behavior: The Role of Vitality and Core Self-Evaluations

Although results from cross-sectional between-person studies suggest a differentiation of employees in good and bad performers, recent studies have challenged this assumption by showing that performance is also dependent on more transient states that vary within individuals. Acknowledging that individuals do not only differ in reference to others, but also in reference to themselves, we integrated the between- and within-person approach in the examination of organizational citizenship behavior (OCB) and counterproductive work behavior (CWB). We propose a model informed by conservation of resources theory in which OCB and minor CWB are predicted by within-person variation in one’s level of vitality, with these relationships being moderated by trait core self-evaluations (CSE). Moderated multilevel Poisson regression analyses revealed that vitality was positively related with OCB and negatively with minor CWB. CSE moderated the relationship between vitality and OCB so that individuals high in CSE engaged in OCB regardless of their vitality levels; however, contrary to our expectations, CSE did not moderate the relationship between vitality and minor CWB. Together, these findings indicate a complex reality underlying the mechanisms that drive the enactment of OCB and CWB.     

Toward a Unified Framework for the Study of Between-Person and Within-Person Structures: Building a Bridge Between Two Research Paradigms

The vast majority of empirical research in the behavioral sciences is based on the analysis of between-person variation. In contrast, much of applied psychology is concerned with the analysis of variation within individuals. Furthermore, the mechanisms specified by psychological theories generally operate within, rather than across, individuals. This disconnect between research practice, applied demands, and psychological theories constitutes a major threat to the conceptual integrity of the field. Following groundbreaking earlier work, we propose a conceptual framework that distinguishes within-person (WP) and between-person (BP) sources of variation in psychological constructs. By simultaneously considering both sources of variation, it is shown how to identify possible reasons for nonequivalence of BP and WP structures as well as establishing areas of convergence. For this purpose, we first introduce the concept of conditional equivalence as a way to study partial structural equivalence of BP and WP structures in the presence of unconditional nonequivalence. Second, we demonstrate the construction of likelihood planes to explore the causes of structural nonequivalence. Third, we examine 4 common causes for unconditional nonequivalence—autoregression, subgroup differences, linear trends, and cyclic trends—and demonstrate how to account for them. Fourth, we provide an empirical example on BP and WP differences in attentiveness.     

The effects of marital status on episodic and semantic memory in healthy middle-aged and old individuals

The present study examined the influences of marital status on different episodic and semantic memory tasks. A total of 1882 adult men and women participated in a longitudinal project (Betula) on memory, health and aging. The participants were grouped into two age cohorts, 35-60 and 65-85, and studied over a period of 5 years. Episodic memory tasks concerned recognition and recall, whereas semantic memory tasks concerned knowledge and fluency. The results showed, after controlling for education, some diseases, chronological age and leisure activity as covariates, that there were significant differences between married and single individuals in episodic memory, but not in semantic memory. Married people showed significantly better memory performances than singles in both subsystems of episodic memory, that is, recall and recognition. Also, the rate of decline in episodic memory was significantly larger for singles and widowed than other groups over the 5-year time period in both age groups. The findings demonstrate that the positive relation found between marriage and health can be extended to the relation between marriage and cognitive performance. This effect might be explained by the role played by cognitive stimulation in memory and cognition.     

Exploring the within-person coupling of sleep and cognition in older African Americans

This study examined the within-person relationship between sleep and cognitive functioning. Fifty community-dwelling African Americans (age range = 50-80 years) were asked to report their sleep duration and quality the previous evening and to complete cognitive measures over 8 occasions within a 2-3 week period. A within-person daily change in sleep duration was significantly associated with worse global cognitive performance. The greater an individual deviated away from his or her average sleep duration on a particular day, the more likely his or her performance would decline. These results demonstrate that the sleep-cognition relationship can be observed at a within-person level of analysis.