Differential effects of normal aging on recollection of concrete and abstract words.

Verbal memory is known to be affected by word features. Concrete words are remembered better than abstract words (concreteness effect), presumably due to the concurrent activation of image-based and/or semantic associations. Vivid remembering during recognition (recollection) has been linked to the hippocampus and is thought to be more affected by healthy aging than familiarity-based recognition. Recent evidence also implicated the hippocampus in the processing of concrete words. Based on these observations, we hypothesized age-related changes in recollection to affect concrete words more than abstract words. This prediction was tested in a cross-sectional design with three consecutive age groups (mean ages 21 years, 42 years, and 61 years). Changes in recollection, but not familiarity, across ages were significantly modulated by word concreteness. Recollection of concrete words showed a steady decline across age, while recollection of abstract words decreased only from young to middle age, leading to a reduced concreteness effect in the oldest group. These findings are consistent with the idea that changes in hippocampally mediated recollective processes during aging affect concrete words more than abstract words.