Free recall and word finding ability in normal aging and senile dementia of the Alzheimer's type: the effect of item concreteness.

This study examined the effect of item concreteness on free recall and word finding ability in three groups: young adults, normal old adults, and individuals with senile dementia of the Alzheimer's type (SDAT). The results of Experiment 1 showed, in addition to an overall decline in recall across the three groups, an attenuation with normal aging of the memory advantage of concrete over abstract words. The SDAT group, however, did not show this attenuation. Experiment 2 compared word finding ability for concrete and abstract items. Word finding was significantly impaired in SDAT but not in normal aging. Furthermore, the SDAT group did much worse on the abstract items. This difficulty with the retrieval of abstract words can explain the unexpected concreteness effect in the SDAT group in Experiment 1. The attenuation of the concreteness effect was predicted on the basis of the communication hypothesis of age-related cognitive decline, which attributes age deficits to a breakdown of the memory network. The results are consistent with the reduced activation of information in this network.