The effect of meaningful stimuli in arbitrary matching-to-sample procedure on stimulus equivalence in younger and older adults

Abstract

Previous research suggests that using at least one meaningful stimulus as a member of an equivalence class may enhance class formation in younger adults and teenagers. As older adults tend to be less likely to establish equivalence classes than younger adults and teenagers, this study aimed to explore the effect of meaningful stimuli on conditional discrimination and stimulus equivalence in older adults. Sixteen younger adults and sixteen older adults were quasi-randomly assigned to two different sequences of training (eight participants in each), with one group first exposed to a condition with all-abstract stimuli and the second condition with one meaningful stimulus in each class. The other group was exposed to the reverse order of conditions. Participants were trained to form three 3-member equivalence classes in each condition in a linear-series training structure with serialized introduction of baseline conditional discriminations. The results suggest that the use of meaningful stimuli as a member of a to-be-formed equivalence class can enhance equivalence class formation in both younger and older adults. However, the effect of meaningful stimuli was greater in younger adults. These findings contribute to further studies on feasible ways to re-establish stimulus control or maintain intact relations in populations where stimulus control is changing.