Does the direction and magnitude of cognitive change depend on initial level of ability?

Longitudinal change in five cognitive abilities was investigated to determine if the direction or magnitude of change was related to the individual's ability level. Adults between 18 and 97 years of age performed three versions of 16 cognitive tests on two occasions separated by an average of 2.7 years. In order to control for influences associated with regression toward the mean, level of ability was determined from scores on the first version of the cognitive tests on the first occasion, and across-occasion change was examined on the second and third versions. Change in every cognitive ability was significantly more negative with increased age. However, there was little indication of ability-dependent change in any of the five cognitive abilities, either in differences between composite scores, or in estimates of latent change. Although there are reasons to expect cognitive change to be less negative at either high or low levels of ability, these data suggest that neither the direction nor magnitude of change is related to initial ability when influences of regression toward the mean are controlled.     

Personality and mood: State-trait relationships

The scores of 33 subjects of the neuroticism scale of the Eysenck Personality Questionnaire correlated more highly with mood levels averaged over the 12 occasions studied than, on average, with mood scores on single occasions, and more highly with mood described in global terms than with scores on each of the original 18 mood scales. Subjects with high neuroticism scores had poorer mood on average and showed greater variation in mood pattern from one occasion to another than did more stable subjects. It is suggested that forms of relatively poor mood may be more varied than forms of good mood, and that, although neuroticism makes a poor mood more likely, the precise composition of this mood on any occasion may be determined by the combination of situation characteristics and person variables. Psychoticism scores correlated significantly, though weakly, with the average scores for some mood scales independently of neuroticism.     

Effects of age and ability on components of cognitive change

Prior experience with a cognitive task is often associated with higher performance on a second assessment, and these experience effects can complicate the interpretation of cognitive change. The current study was designed to investigate experience effects by obtaining measures of cognitive performance separated by days and by years. The analyses were based on data from 2017 adults with two longitudinal occasions, of whom 948 had also completed a third occasion, with each occasion consisting of three parallel versions of the tests on separate sessions. Change across short intervals was typically positive, and greater among older adults and adults with low levels of cognitive ability, whereas change over intervals of approximately three years was often negative, particularly at older ages. In contrast to the expectation that change over short intervals might be informative about change over longer intervals, relations between short-term change and long-term change were negative, as the individuals who gained the most with assessments separated by days tended to experience the greatest losses across assessments separated by years.     

Use of a virtual reality car-driving stressor in cardiovascular reactivity research

Eighteen subjects (11 males, 7 females) completed a virtual reality car-driving stressor on two occasions several weeks apart. Immediately before and throughout task performance, blood pressure, cardiac output, and total peripheral resistance were assessed. Reactivity scores were calculated for each parameter for each subject as the arithmetic difference between task level and baseline level. The task elicited considerable hemodynamic activation on each occasion of testing, as well as high levels of self-reported task realism, engagement, excitement, and nervousness. Correlation analyses of both absolute and reactivity scores revealed evidence of test-retest reliability. Males were found to exhibit greater absolute levels of and greater increases in systolic blood pressure. The development of tasks suitable for inclusion in a battery of behavioral stressors, responses to which may help identify those at risk for later disease, is of considerable interest in cardiovascular behavioral medicine. The present findings suggest that the virtual reality car-driving task may be useful in this context.     

Personality measurement, faking, and employment selection

Real job applicants completed a 5-factor model personality measure as part of the job application process. They were rejected; 6 months later they (n = 5,266) reapplied for the same job and completed the same personality measure. Results indicated that 5.2% or fewer improved their scores on any scale on the 2nd occasion; moreover, scale scores were as likely to change in the negative direction as the positive. Only 3 applicants changed scores on all 5 scales beyond a 95% confidence threshold. Construct validity of the personality scales remained intact across the 2 administrations, and the same structural model provided an acceptable fit to the scale score matrix on both occasions. For the small number of applicants whose scores changed beyond the standard error of measurement, the authors found the changes were systematic and predictable using measures of social skill, social desirability, and integrity. Results suggest that faking on personality measures is not a significant problem in real-world selection settings.     

A psychometric comparison of the Beck Depression Inventory-II in English and Spanish

The Beck Depression Inventory-II (BDI-II; A. T. Beck, R. A. Steer, & G. K. Brown, 1996) is a widely used measure of depressive symptomatology originally authored in English and then translated to Spanish. However, there are very limited data available on the Spanish translation. This study compared the psychometric characteristics of the BDI-II in Spanish and English in a sample of 895 college students. The instrument was administered twice with a 1-week interval, either in the same language on both occasions or in a different language on each occasion. Results show strong internal consistency and good test-retest reliability in both languages. Confirmatory factor analysis demonstrated that the published English-language factor structure showed good fit with data from the Spanish instrument. Among bilingual participants who took the BDI-II in both languages, there was no significant language effect. These data provide initial evidence of comparable reliability and validity between the English and Spanish BDI-II in a nonclinical sample.     

The effect of multiple indicators on the power to detect inter‐individual differences in change

Hertzog et al. evaluated the statistical power of linear latent growth curve models (LGCMs) to detect individual differences in change, i.e., variances of latent slopes, as a function of sample size, number of longitudinal measurement occasions, and growth curve reliability. We extend this work by investigating the effect of the number of indicators per measurement occasion on power. We analytically demonstrate that the positive effect of multiple indicators on statistical power is inversely related to the relative magnitude of occasion‐specific latent residual variance and is independent of the specific model that constitutes the observed variables, in particular of other parameters in the LGCM. When designing a study, researchers have to consider trade‐offs of costs and benefits of different design features. We demonstrate how knowledge about power equivalent transformations between indicator measurement designs allows researchers to identify the most cost‐efficient research design for detecting parameters of interest. Finally, we integrate different formal results to exhibit the trade‐off between the number of measurement occasions and number of indicators per occasion for constant power in LGCMs.     

Note on the “longitudinal factor analysis” model

The “longitudinal factor analysis” model, which uniquely resolves factors from two occasions of data representing the same persons measured on the same test battery, is shown to be derivable by application of canonical correlation procedures to factor scores. Interpreted in this light, it is suggested that, in attaining its objective, “longitudinal factor analysis” maximizes temporal stability of factor scores—an emphasis which may be warranted for some types of change but not for others.     

What conservation anticipation reveals about cognitive change

A long-running debate about the nature of the thinking involved in conservation judgments resulted in postulating the existence of two different processes. According to the pluralist approach to cognitive development, the two processes can be simultaneously activated with different weights for different children and are likely to interact. A semi-longitudinal study that tests the pluralist approach is reported. The experimental procedure was based on earlier work by Acredolo and Acredolo, 1979, Acredolo and Acredolo, 1980. Children from the last year of nursery school (mean age: 5 years and 6 months) were individually tested in two successive occasions separated by a 3-month interval. The first test occasion consisted of a sequence of liquid-conservation-anticipation and level anticipation tasks. This same sequence was reproduced during the second test occasion, which ended with a classical conservation task. Observed patterns of correct-incorrect answers contradict the predictions of a developmental sequence assumed by the Piagetian model. The patterns of change were compatible with a pluralist approach which hypothesizes different routes in the development of conservation.     

Change in cognitive functioning associated with apoE genotype in a community sample of older adults

The influence of a genetic risk factor, apolipoprotein E (apoE) epsilon4 variant, was assessed in older adults aged 70 to 94 on 3 occasions over 7 years. The results of latent growth curve analyses are reported for individuals genotyped for apoE at the 2nd measurement occasion (n = 601) and for a subsample of individuals without probable or definite dementia during the 1st or 2nd occasion (n = 434). ApoE-epsilon4 status was a significant predictor of level and change in memory performance and change in speed performance in the full sample, and of initial level and change in memory performance in the nondemented subsample. These results support previous findings that apoE-epsilon4 is associated with accelerated memory deterioration in individuals without clinical dementia.     

Situational effects may account for gain scores in cognitive ability testing: A longitudinal SEM approach

Mean gain scores for cognitive ability tests between two sessions in a selection setting are now a robust finding, yet not fully understood. Many authors do not attribute such gain scores to an increase in the target abilities. Our approach consists of testing a longitudinal SEM model suitable to this view. We propose to model the scores' changes of a battery of tests between two sessions with a single factor, namely the change in the situational component of the scores. The situational component encompasses all effects due to the specificity of the state of the person in the current situation (e.g., anxiety level, tiredness, test-taking practice) and is allowed to vary from one session to another. By definition, this single component is supposed to influence all tests at a given session. In particular cases such as high-stake selection settings, where applicants are likely to train themselves before retaking the tests, situational factors might even suffice to explain mean score increases. Empirically, our latent change model closely fitted the scores of 752 applicants for entry into the French Aircraft Pilot Training, gathered on a set of three tests (visual perception, mechanical comprehension, and selective attention). Gain scores of moderate to strong effect sizes could be explained by common situational effects, with no need for admitting change on ability components. Therefore, gain scores may be understood as construct-irrelevant changes.     

The Development of New Tests of Source Memory and a New Approach to the Testing of Equivalence of Parallel Versions

The principal aim of this study was to develop tests of source memory in both the verbal and visuo-spatial domains, which would be brief and easy to use in clinical and population settings. Source memory, that is, memory for context or attributes, is very vulnerable to the effects of ageing and to the early stages of dementia. Because longitudinal studies of cognitive function, including clinical trials, involve repeat testing, practice effects may hamper interpretation when identical tests are administered on each occasion. Accordingly, we developed parallel versions of each of the source memory tests. Rather than assuming equivalence by design, we tested the parallel versions to determine whether they were in fact equivalent in difficulty. We also explored the use of different analytic approaches to establishing equivalence. We report the results of a study in which we compared within- and between-subject performance on three parallel versions of visuo-spatial and verbal source memory tests, as well as three parallel versions of standard tests of episodic memory (word list recall) and executive function (letter fluency, category fluency, ideational fluency) in a sample of healthy elderly volunteers. Participants were tested on three occasions separated by 1 week, and test versions were counterbalanced across test sessions. We also examined performance in a group of participants tested on one occasion only, with test versions being allocated at random. We found that for a number of tests, versions which were designed to be parallel, failed to produce equivalent performance in our sample. We show how the results of this study may be of general use to researchers wishing to select particular versions of the tests in our battery. We also urge researchers to be cautious when using parallel versions of other tests. The careful matching or random allocation of items to parallel versions of a test is no guarantee that performance on the different versions will be equivalent.     

A base-free measure of change

A model for the measurement of the discrepancy between two scores is presented and discussed as a paradigm for the study of growth or experimentally produced change. The model assumes two tests or measures differing in complexity, and it analyzes the true difference between the test scores into a component that is entirely dependent on the first or base-line test and a second component that is entirely independent of it. Equations for estimating both components are given and these are compared with other measurement efforts with similar goals.     

Effects of age on time-dependent cognitive change

Interpretation of cognitive change has been complicated because different influences on change are not easily distinguished. In this study, longitudinal cognitive change was decomposed into a component related to the length of the interval between test occasions (i.e., time-dependent change) and a component unrelated to the test-retest interval (i.e., time-independent change). Influences of age on the two hypothesized components were investigated in a sample of more than 1,500 adults for whom the intervals between test occasions ranged from less than 1 year to more than 8 years. Although overall change was negatively related to age for all seven composite cognitive variables, little or no effect of age was apparent for the time-dependent component of change. The results suggest that the relations between age and cognitive change over intervals of less than 8 years are largely influenced by factors operating at or near the initial test occasion.     

Stable unstable reliability theory

Classical reliability theory assumes that individuals have identical true scores on both testing occasions, a condition described as stable. If some individuals' true scores are different on different testing occasions, described as unstable, the estimated reliability can be misleading. A model called stable unstable reliability theory (SURT) frames stability or instability as an empirically testable question. SURT assumes a mixed population of stable and unstable individuals in unknown proportions, with w(i) the probability that individual i is stable. w(i) becomes i's test score weight which is used to form a weighted correlation coefficient r(w) which is reliability under SURT. If all w(i) = 1 then r(w) is the classical reliability coefficient; thus classical theory is a special case of SURT. Typically r(w) is larger than the conventional reliability r, and confidence intervals on true scores are typically shorter than conventional intervals. r(w) is computed with routines in a publicly available R package.     

Approximate methods in calculating discriminant functions

Approximate methods of solving for discriminant functions have been tried on three sets of data. The principal illustration is the problem of finding a weighted sum of scores, on four psychological tests, so that men and women may be distinguished most clearly. The work starts from the complete solution, due to R. A. Fisher, where it is necessary to solve as many simultaneous equations, dependent on the standard deviations of the tests and their mutual correlations, as there are tests. It is proposed, by way of numerical simplification, that a set of equations be substituted where some one quantity replaces all the correlations. A solution is obtained where the weights to be assigned the tests are very simply expressed in terms of differences between the mean values of tests, the standard deviations of tests, and the said quantity. The difficulty remains of finding an estimate of the arbitrary constant that will give good discrimination. If an optimal solution is made a result is obtained which, in the three sets of data considered, is almost indistinguishable from that yielded by the complete solution. The calculation of this optimal common quantity is, however, itself so considerable that another estimate, previously suggested by R. W. B. Jackson, appears more profitable. This estimate is derived simply from the variability between the total scores for each subject and the variability of each test. Using this estimate, the discriminant functions can be rapidly calculated; the results compare very favorably, in the case of the data considered, with those from the complete solution.The present work was done while the writer was employed by the Ontario Department of Health.     

Congruence and temporal stability of multimiethod profiles: A new pair of personality variables

Congruence and temporal stability of multimethod profiles within the individual subject were studied as proposed new personality variables in a pool of seven small groups of graduate students in clinical psychology (N= 51) Sex differences were minimal A Stability Index was derived from (a) Q correlation stability coefficients obtained from the single method profiles of an inventory, self-ratings, and mean ratings by others, or (b) absolute difference scores between the composite profiles on occasion 1 and occasion 2 A Congruence Index was derived from (a) Q correlation coefficients obtained from each pair of profiles measured by the three methods for each subject, or (b) mean absolute difference scores obtained from each pair of method profiles These moderately correlated indices were used as dependent variables in stepwise multiple regression analyses, in which scores on a profile of 21 personality variables served as independent variables Although the difference score method was at least as effective as the correlational method in predicting congruence, the Q correlational method was superior in all other analyses conducted in this study Persons high in temporal stability seem to maintain an intellectually searching and interpersonally affiliative approach to the environment, showing little hostility and little tendency to seek change in current life circumstances The highly congruent individual seeks a positive nurturant interaction with other persons, gains pleasure from both sensory and interpersonal experiences, and shows little discontent with present life circumstances     

Reliability of psychophysiological assessment

In order to assess the reliability of psychophysiological recording, 15 subjects were assessed on multiple response measures (forehead EMG and forearm flexor EMG, heart rate, skin resistance level, hand surface temperature and cephalic vasomotor response), under multiple stimulus conditions (baseline, self-control, cognitive and physical Stressors), on multiple occasions (Days 1, 2, 8 and 28). Three forms of reliability coefficients were computed for each response measure: coefficients on absolute scores, coefficients on change scores from baseline to stressful conditions and coefficients on percent change from baseline. Only frontal EMG appeared to have consistently high absolute reliability coefficients, with hand surface temperature having high reliability if sessions are repeated within 1 week. Heart rate was less consistently reliable. Treating the responses as relative measures did not increase their reliability; indeed, hand surface temperature was completely unreliable when examined in this fashion. Implications of this study for behavioral medicine, biofeedback and anxiety-based disorders research, as well as Lang's tripartite response system model of fear and emotion, are discussed.