The Japanese Society for Cognitive Psychology

The current study examined age-related differences on three categorization tasks, a single-dimensional rule-based, a disjunctive rule-based, and a similarity-based task, and tested the effect of verbalization before categorization trials. As previous papers demonstrate, older adults find the disjunctive rule-based categories more difficult to learn than family resemblance-based categories, in contrast to younger adults. A simple pre-learning verbalization of category exemplars led to poorer learning performance on disjunctive rule-based learning for both age groups. Hand movement data collected by mouse tracking revealed that the disjunctive rule-based categories, which were difficult to older adults, involved huge competitive interferences, implying that younger adults experienced heavy inhibition loads in learning such categories. The data support the dual system model of category learning that there are different mechanisms for rule-based and non-rule based categories, and that the differential age-related performance decline in disjunctive categories can be due to the declines in inhibitory functions by aging.