Adult age differences in repetition priming: a meta-analysis.

This article reports a meta-analysis comparing the size of repetition priming effects in young and older adults. The main analysis included 39 effect sizes. Of these, 23 effect sizes could be classified as involving item priming and 16 as involving associative priming. The weighted mean effect size for the age difference was .304, with a confidence interval from .217 to .392. Because the confidence interval did not include 0, the hypothesis of no age difference in repetition priming was rejected. Subsidiary analyses, however, revealed that the weighted mean effect size for repetition priming was smaller than those for recognition or recall measures from the set of experiments included in the effect-size meta-analysis. Difficulties in drawing conclusions about process dissociations in old age in the face of only a partial dissociation in experimental measures are considered.