Maddox · Memory & cognition 2015 · controlled laboratory experiment · n=?

Retrieval practice and spacing effects in young and older adults: An examination of the benefits of desirable difficulty.

Level 2 - randomized trial

Laboratory experiment with controlled factorial manipulations (graded by design analogy for non-clinical cognitive psychology)

PubMed 25616776 · doi:10.3758/s13421-014-0499-6 · record verified 2026-08-26

What was done

Two laboratory experiments examined how varying amounts of continued retrieval practice (one, three, or five tests) influence long-term memory retention across young and older adults. Experiment 1 manipulated test lag, and Experiment 2 manipulated test spacing (spaced vs. massed). Response latency during acquisition was recorded as a proxy for retrieval difficulty, and final retention analysis was conditionalized on acquisition-phase retrieval success.

What was found

The abstract reports directional findings without numerical values, effect sizes, or sample sizes. In Experiment 1, repeated testing in the short-lag condition produced consistent increases in retention, whereas repeated testing in the long-lag condition produced diminishing benefits across both age groups. In Experiment 2, repeated spaced testing enhanced retention compared with a single spaced test in both age groups; however, repeated massed testing enhanced retention over a single test only in young adults. Response latencies across both experiments aligned with desirable difficulty predictions.

Why it matters

This study shows that spacing and retrieval practice remain effective memory-enhancement tools in older adults, though older adults fail to derive the marginal benefits from repeated massed retrieval seen in younger adults.

Limits

The abstract provides no sample sizes (n is unstated), numerical data, confidence intervals, or p-values. Exact retention delays and stimulus types are not specified in the abstract, and findings from simplified laboratory memory tasks may not fully generalize to naturalistic learning environments.

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