Five views of a secret: does cognition change during middle adulthood?

This study examined five aspects of change (or stability) in cognitive abilities in middle adulthood across a 12-year period. Data come from the Interdisciplinary Study on Adult Development. The sample consisted of N = 346 adults (43.8 years on average, 48.6% female). In total, 11 cognitive tests were administered to assess fluid and crystallized intelligence, memory, and processing speed. In a first series of analyses, strong measurement invariance was established. Subsequently, structural stability, differential stability, stability of divergence, absolute stability, and the generality of changes were examined. Factor covariances were shown to be equal across time, implying structural stability. Stability coefficients were around .90 for fluid and crystallized intelligence, and speed, indicating high, yet not perfect differential stability. The coefficient for memory was .58. Only in processing speed the variance increased across time, indicating heterogeneity in interindividual development. Significant mean-level changes emerged, with an increase in crystallized intelligence and decline in the other three abilities. A number of correlations among changes in cognitive abilities were significant, implying that cognitive change

Correlated change in memory complaints and memory performance across 12 years

The present study examines whether the relationship between memory complaints and memory performance is better assessed by analyzing the mutual development. Five hundred participants, averaging 62.9 years of age at first measurement, were measured three times over 12 years. After establishing partial strong factorial invariance, correlations between levels and between slopes of memory performance and memory complaints were estimated using second-order latent growth curve models. The relationship between slopes was found to be three times larger than the relationship between levels, indicating that assessing the commonality in change is more informative than assessing the relationship at a given time point

Stability and change in typical intellectual engagement in old age across 5 years

Objectives: Typical intellectual engagement (TIE) is related to cognitive development across the life span, but the development of TIE itself has not been examined. In the present study, structural change, differential change, absolute change, stability of divergence and the generality of changes in the four TIE-factors Abstract Thinking, Problem Solving, Reading, and Intellectual Curiosity across five years were examined in older adults. Method: Datacame from the Zurich Longitudinal Study on Cognitive Aging. 233 individuals, 73 years on average at first measurement occasion (2005) were reassessed after five years. Confirmatory factor analyses and latent change score models were applied. Results: Factor covariances were equal across time, implying structural stability. Coefficients for differential stability were around .80, implying small significant mean level changes for Problem Solving and Intellectual Curiosity. No changes in divergence emerged. Change correlations between the factors were in the medium to large range. Discussion: Across five years, TIE remained relatively stable on a group-level. However, pronounced interindividual differences emerged. Also, although the changes in factors shared a substantial amount of variance, the development of the factors was not completely parallel