Intraindividual variability, change, and aging: conceptual and analytical issues.

Mike Martin; Scott M Hofer

doi:10.1159/000074382

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Intraindividual variability, change, and aging: conceptual and analytical issues.

Mike Martin·Scott M Hofer

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Abstract

BACKGROUND: Developmental researchers use a variety of research designs to examine aging-related changes. Most longitudinal studies of aging are based on research designs that feature successive, widely spaced, assessments to estimate changes in cognitive performance. Such designs assume that short-term variations in cognitive performance are small relative to long-term changes or have modeled such phenomena as nuisance parameters. OBJECTIVE: There is now sufficient empirical evidence to establish intraindividual cognitive variability as a systematic source of individual differences and of important predictive value for aging-relevant outcomes. METHODS: After an overview of types of change, potential underlying processes, and adequate analytic designs, we discuss consequences for lifespan aging research. RESULTS: We emphasize that interpretations of both cross-sectional and longitudinal results need to consider and specify theoretical assumptions about short-term and long-term changes. CONCLUSIONS: Above and beyond the analysis of long-term mean changes, short- term changes are an important aspect of aging-related change, and their analysis may help to explain psychological processes of adaptation.

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Mike Martin, Scott M Hofer. Intraindividual variability, change, and aging: conceptual and analytical issues.. https://doi.org/10.1159/000074382

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