Explaining vocabulary knowledge in adulthood through comparison with knowledge of math concepts

Previous research has assumed that all types of semantic knowledge are similarly affected by aging. We investigate whether knowledge of vocabulary and math concepts show comparable lifetime change. A sample of 252 participants aged 17–91 completed two multiple-choice tasks that examined knowledge of infrequent word meanings and knowledge of basic math concepts. Up to age 64, vocabulary scores improved, whereas math scores remained stable. After that age, vocabulary scores remained stable, while math scores declined. We suggest that the fact that the learning and use of infrequent vocabulary are incidental, incremental, and contextual contributes to maintenance of word knowledge into old age. In contrast, learning of basic math concepts occurs relatively early in life in an intentional manner, and both learning and use of these concepts involve constrained contexts. Thus, the nature of the acquisition and use of semantic knowledge across the lifespan affects its fate in old age.