Short-term fluctuations in elderly people's sensorimotor functioning predict text and spatial memory performance: The Macarthur Successful Aging Studies.

BACKGROUND: While age-related increases of between-person variability in a variety of cognitive measures are commonly reported in cross-sectional studies, the nature of short-term intraindividual fluctuation in elderly people's performance is relatively unexplored. OBJECTIVE: The goal of the present study is to examine short-term fluctuations in elderly people's sensorimotor functioning and their relations to individual differences in verbal and spatial memory. METHODS: Fluctuations in old adults' (mean = 75.71 years, SD = 6.93 years) sensorimotor performance were investigated by biweekly measurements spanning approximately 7 months. Sensorimotor performance was measured by three walking tasks, including the duration and the number of steps taken to walk a 360-degree circle and to walk 10 feet both at normal and fast pace. Performances of verbal and spatial memory were assessed by weekly measurements of digit memory span, memory for short text and spatial recognition. RESULTS: The magnitude of intraindividual fluctuation in most sensorimotor and memory tasks examined was at least half as great as the level of individual differences across persons. In addition, intraindividual fluctuation in sensorimotor performance is a relatively stable individual attribute, which correlates positively with age and negatively with the levels of sensorimotor, text and spatial memory performance. Although a substantial amount of individual differences in intraindividual fluctuation was shared with mean performance level, variance component and hierarchical regression analyses showed that intraindividual fluctuation in walking steps added significant independent contribution over and above that given by level of performance in predicting text and spatial memory. CONCLUSION: Taking these results together, we suggest that intraindividual fluctuations in elderly people's performance should not be ignored or simply treated as measurement error; rather, they are potentially important empirical variables for understanding sensory and cognitive aging and the nature of intraindividual response variations in general.

Emotional experience in everyday life across the adult life span.

Age differences in emotional experience over the adult life span were explored, focusing on the frequency, intensity, complexity, and consistency of emotional experience in everyday life. One hundred eighty-four people, age 18 to 94 years, participated in an experience-sampling procedure in which emotions were recorded across a 1-week period. Age was unrelated to frequency of positive emotional experience. A curvilinear relationship best characterized negative emotional experience. Negative emotions declined in frequency until approximately age 60, at which point the decline ceased. Individual factor analyses computed for each participant revealed that age was associated with more differentiated emotional experience. In addition, periods of highly positive emotional experience were more likely to endure among older people and periods of highly negative emotional experience were less stable. Findings are interpreted within the theoretical framework of socioemotional selectivity theory.

A Comparison of Pseudo-Maximum Likelihood and Asymptotically Distribution-Free Dynamic Factor Analysis Parameter Estimation in Fitting Covariance-Structure Models to Block-Toeplitz Matrices Representing Single-Subject Multivariate Time-Series.

The study of intraindividual variability pervades empirical inquiry in virtually all subdisciplines of psychology. The statistical analysis of multivariate time-series data - a central product of intraindividual investigations -requires special modeling techniques. The dynamic factor model (DFM), which is a generalization of the traditional common factor model, has been proposed by Molenaar (1985) for systematically extracting information from multivariate time- series via latent variable modeling. Implementation of the DFM model has taken several forms, one of which involves specifying it as a covariance-structure model and estimating its parameters from a block-Toeplitz matrix derived from the multivariate time-ser~es. We compare two methods for estimating DFM parameters within a covariance-structure framework - pseudo-Maximum Likelihood (p-ML) and Asymptotically Distribution Free (ADF) estimation - by means of a Monte Carlo simulation. Both methods appear to give consistent model parameter estimates of comparable precision, but only the ADF method gives standard errors and chi-square statistics that appear to be consistent. The relative ordering of the values of all estimates appears to be very similar across methods. When the manifest time-series is relatively short, the two methods appear to perform about equally well.

Intraindividual variability in perceived control in an older sample: the MacArthur successful aging studies.

Two aspects of perceived control, locus of control (LOC) and perceived competence (COM), command significant attention in personality and aging research. Mainly, these concepts are regarded as stable variables of considerable promise for predicting a range of outcomes. The authors concentrate on week-to-week within-person variability in self-reported LOC and COM. Using data collected over 7 months, the authors first demonstrates that the responses of a panel of older participants are structurally consistent with dominant conceptions of perceived control and that the responses maintain an underlying structure over the frequently repeated protocol. They next show that the within-person variation over weekly measurements is coherent information rather than "noise" and that individual differences in magnitude of week-to-week variability are a relatively stable attribute that predicts mortality status 5 years later. Implications of the findings for both methodological and substantive concerns are discussed.

Structure and variation of mood in individuals with Parkinson's disease: a dynamic factor analysis.

Mood structure was examined among individuals diagnosed with Parkinson's disease. Twelve individuals completed a measure of positive and negative affect for 70 consecutive days. Mood structure was determined by using dynamic factor analysis (DFA) models that account for both concurrent and lagged relationships in repeated measurements. Five individuals had sufficient variability in positive and negative affect to conduct DFA on both sets of variables. Results showed the presence of 2 2-factor 1-lag models, 2 1-factor 1-lag models, and a P-technique model. There was sufficient variability in positive affect to conduct DFA on positive affect for the entire sample. Two individuals displayed 2-factor 1-lag models, 6 individuals had 1-factor 1-lag models, and 4 individuals showed P-technique models. Implications of lagged relationships are discussed from substantive and methodological perspectives.

Social self-efficacy and short-term variability in social relationships: the MacArthur successful aging studies.

Dealing with others entails both stability and short-term variability of the functions and outcomes of social relationships. The authors argue that patterns of short-term intraindividual variability in social relationships and self-efficacy beliefs contribute interpretable information about social adaptation. On the basis of 23 repeated weekly measurements of a sample of 32 participants ages 56 to 88 years, the authors examined the extent to which fluctuations in perceived relational outcomes are related to fluctuations of social self-efficacy. Results showed that individuals differ systematically in respect to the extent to which they experience and display fluctuations in self-efficacy and availability of social relationships. Moreover, when individuals perceive others to be available across time, social self-efficacy beliefs are stronger and fluctuate less across time.

Affective states in normal and depressed older people.

Ratings on a 10-item affect checklist yielding composite positive affect and negative affect scores were made daily for 30 days by older people in residential care: 19 were diagnosed as having major depression, 21 had minor depression, and 37 were without psychiatric diagnosis ("normal"). Mean levels of positive affect were highest in normal people and least in those with major depression; negative affect was lowest in normal ones and highest in those with a major depression. Variability was least among those with major depression in positive affect and among normal people in negative affect, while residents with minor depression showed some tendency, although inconsistent, toward greater day-to-day variability in positive affect. Patterns of invariance were such that those with major depression tended to be consistently lacking in positive affect but were variable in negative affect; normal people showed variability in positive affect but a relatively unvarying lack of negative affect. Clinical major depression was thus characterized less by "pervasive" depressive affect than by anhedonia.

The state component in self-reported worldviews and religious beliefs of older adults: the MacArthur Successful Aging Studies.

Meaningful and measurable aspects of short-term intraindividual variability have been established in what are conceptualized to be relatively stable interindividual differences dimensions. Illustrative are anxiety and other temperament traits as well as certain kinds of cognitive abilities. Reclamation of "signal" from the "noise" of intraindividual variability has rested heavily on research designs that involve frequently repeated observations. We extended this line of research to other trait-like domains by examining biweekly self-reports of world views and religious beliefs of a sample of elderly participants. The results indicated that not only is there occasion-to-occasion variability in the self-reports but the structure of these fluctuations is consistent over time and bears considerable resemblance to structures reported from cross-sectional data.

Selection and related threats to group comparisons: an example comparing factorial structures of higher and lower ability groups of adult twins.

Is it possible to construct valid explanations of behavioral phenomena from differences found among naturally existing groups? Many of psychology's cherished findings in such domains as intellectual performance and temperament rest on differences of this kind. A venerable and rich literature on selection and selection effects both reminds us that naturally existing groups might or might not derive from a common parent population and warns that valid decisions between these alternatives are often jeopardized by the very methods on which those decisions rest. We examine these matters within the context of intellectual performance, illustrate key points with an analysis of data, and examine the implications for current research on differences in ability levels.

Genetic and environmental effects on openness to experience, agreeableness, and conscientiousness: an adoption/twin study.

Previous research has indicated that extraversion and neuroticism are substantially affected both by genotype and environment. This study assesses genetic and environmental influences on the other three components of the five-factor model of personality: Openness to Experience, Agreeableness, and Conscientiousness. An abbreviated version of the NEO Personality Inventory (NEO-PI) was administered to 82 pairs of identical twins and 171 pairs of fraternal twins reared apart and 132 pairs of identical twins and 167 pairs of fraternal twins reared together. Estimates of genetic and environmental effects for Openness and Conscientiousness were similar to those found in other studies of personality: Genetic influence was substantial and there was little evidence of shared rearing environment. Results for Agreeableness were different: Genetic influence accounted for only 12% of the variance and shared rearing environment accounted for 21% of the variance. Few significant gender or age differences for genetic and environmental parameters were found in model-fitting analyses.

Importance of shared genes and shared environments for symptoms of depression in older adults.

The Center for Epidemiologic Studies-Depression scale was administered to 68 identical and 161 fraternal twin pairs reared apart and 114 identical and 138 fraternal pairs reared together to ascertain relative genetic and environmental contributions to individual differences in self-reported depressive symptoms. Intraclass correlations and model fitting indicated that genetic influences explained 16% of the variance in total depression scores and 19% for the Psychomotor Retardation and Somatic Complaints subscale, but heritability was minimal for the Depressed Mood and Well-Being subscales. Influence of family rearing context played a substantial role in explaining twin similarity, whereas unique life experiences accounted for the greatest proportion of variance. Significant age group differences were observed, with heritability greater in twins of 60 years of age or older than in twins under 60, especially for Psychomotor Retardation.

The structure of variation in affect among depressed and nondepressed elders.

The intraindividual variability of self-ratings of 10 affects was studied in 69 older residents of a long-term care facility. Each person rated his or her affective state over 30 days. P-technique factor analysis was applied to each subject's ratings. In general, the expected two-factor structure showing one positive and one negative factor emerged from both traditional R-analysis and from "chain P-analysis" (all subjects' ratings pooled after standardizing within subjects). Because many subjects gave invariant ratings on one or more affect terms, only 28 P-analyses could be performed, of which 12 yielded one-factor solutions, 16 yielded two-factor solutions (10 the expected two factors), and 5 failed to converge. Possible reasons for the only partial intraindividual replication of the interindividual factors are discussed.

Age differences in genetic and environmental influences for health from the Swedish Adoption/Twin Study of Aging.

This cross-sectional study explored the etiology of variability in self-reported health. The sample comprises adult twins participating in the Swedish Adoption/Twin Study of Aging and includes identical (MZ) and fraternal (DZ) twin pairs who have been reared together or reared apart. Two different components of overall health status are analyzed: an index of chronic health problems and self-rated health. Height and weight were included to assess the representativeness of the twin data. Individual differences increased across age for both measures of health, and there were significant age differences in the genetic and environmental etiologies of this variation. Genetic variance showed a twofold increase for chronic illness up until age 70. Environmental influences during adulthood appear important later in life. For self-rated health, genetic effects were important in the older age groups; however, the increase in total variation is predominantly due to unique environmental influences.

Types of change: application of configural frequency analysis in repeated measurement designs.

Many researchers are concerned both with intraindividual change patterns and interindividual differences and similarities in those change patterns. Configural Frequency Analysis (CFA) provides a way to identify overrepresentations (types) and underrepresentations (antitypes) in the frequencies of multiple variable classifications organized to reflect patterns of change. Three methods of CFA for analyzing repeated measures data are considered. To establish trends, two of them require at least ordinal data and the third requires interval data. Data analysis and the interpretation of results are illustrated. CFA is compared with residual analysis from log-linear modeling.

Reporting structural equation modeling results in Psychology and Aging: some proposed guidelines.

Structural equation modeling (SEM) is now widely used in social and behavioral science research. SEM provides the possibility of fitting, and evaluating the fit, of well-specified, theoretical models to empirical data--more generally, of testing elaborated psychological theories. The options available to users of these approaches are many and varied. Popular SEM computational software packages, such as LISREL and EQS, provide a large amount of information, and there is some uncertainty as to what should be routinely reported. A series of guidelines are proposed for reporting SEM results in articles submitted to Psychology and Aging. The suggested guidelines ask authors using SEM methodology to provide important analysis information that will enable readers to evaluate the findings.

The Swedish Adoption Twin Study of Aging: an update.

The Swedish Adoption/Twin Study of Aging (SATSA) is a longitudinal program of research in gerontological genetics which is currently in its fifth year. The base population is comprised of 351 pairs of twins reared apart and 407 matched control pairs of twins reared together who responded to a questionnaire (Q1) in 1984. Two additional stages of SATSA have recently been completed: a longitudinal follow-up questionnaire mailed out in 1987 (Q2) and extensive in-person testing (IPT1) which included a health examination and cognitive battery. A second wave of IPT was started in January 1989. A summary of some of the major findings from Q1 and a description of IPT1 are reported.

Multi-modal selection effects in the study of adult development: a perspective on multivariate, replicated, single-subject, repeated measures designs.

Some of the selection issues that bear upon the conduct of research using multivariate, replicated, single-subject repeated measures designs are examined and their implications for the study of developmental phenomena discussed. The choices of participants, variables, occasions of measurement, etc., made in the conduct of empirical research all involve some kind of selection. These choices, therefore, introduce selection effects into collected data which, in turn, threaten the generalizability of one's conclusions. Data analyzed for single subjects, for example, are suspect regarding generalizability to other individuals. While the limits of generalizability to persons is a concern to be taken seriously, the concern properly applies to all modes of data classification. Discussions of the importance of person selection emphasize representative sampling (of persons) and generalization to populations of persons. Attention to the selection of variables has led to a focus on multivariate approaches to measurement. For the developmentalist, the occasions mode, which is either implicitly or explicitly involved in definitions of change, is especially relevant to concerns about generalizability. Whether one considers stability or change, the effects of temporal selection ought to be a central concern in designing research.