Age is not necessarily aging: another step towards understanding the "clocks" that time aging

Area of Science:

• Gerontology
• Cognitive Neuroscience
• Lifespan Psychology

Background:

• Cross-sectional age difference correlations are commonly used in aging research to infer associations between aging processes.
• This approach is criticized for its limitations in accurately representing the interdependence of aging changes.
• Long-standing issues in lifespan research include challenges in inferring aging from age differences and using age as a proxy for aging.

Purpose of the Study:

• To highlight the limitations of cross-sectional age difference correlations in aging research.
• To connect this concern with broader issues in lifespan research.
• To introduce alternative, underutilized research approaches for studying cognitive aging.

Main Methods:

• Analytical examination of cross-sectional data limitations.
• Discussion of confounding factors like cohort and mortality selection effects.
• Review of alternative methodological and theoretical approaches in gerontology.

Main Results:

• Cross-sectional information from age-heterogeneous samples is unsuitable for understanding interdependence between aging changes.
• Variance sources independent of change rates, such as selection effects, are confounded in age-heterogeneous designs.
• Chronological age is a superficial indicator in aging research.

Conclusions:

• Rethinking process-oriented theories over solely age-oriented ones is crucial for understanding cognitive aging.
• Integrating advances in statistical analysis of dynamic processes and cognitive/computational neurosciences is recommended.
• Developing more explicit theories of cognitive aging requires new methodological and empirical strategies.