Reading focus
Syllabus: How Do We Adapt as We Grow Older?
Start by comparing the question in the title with the evidence used to answer it. Follow how retest effects could mask change, while keeping cohort differences and selection as competing considerations.
A question to consider. Design one additional comparison that could help explain why people tested twice improve even though older age groups score lower.
Why this reading
Age-group comparisons and repeated testing can suggest different trajectories. Salthouse investigates whether experience with the tests helps explain that discrepancy. The paper makes the design of an aging study part of the question it is trying to answer.
Before you read
A cohort shares a historical period of birth and associated experiences. A retest effect is a change attributable to previous testing. Neither a difference between age groups nor a change within a person isolates the effect of aging by itself.
Read for
- Compare the three ways the paper estimates the contribution of retesting.
- Identify the assumptions needed to separate practice from other sources of change.
- Keep the selected cognitive tasks and recruited sample in view when interpreting the title.
Consider afterwards
- If repeated scores remain stable while older age groups score lower, what additional comparison would help distinguish practice, historical experience, and change with age?
Editorial context
The central analyses concern selected healthy, educated adults under sixty and tasks showing negative cross-sectional age trends. They do not identify one onset of decline for all abilities. Schaie's commentary challenges the inference. In his reply, Salthouse argues for investigating multiple influences on both designs, not discarding longitudinal evidence.