Proceedings of the Annual Meeting of the Cognitive Science Society

Comparison can support category learning by highlighting shared similarities or diagnostic differences between categories. We examined how comparison type (match vs. contrast vs. single-item control) influences featural category learning and whether these effects depend on category confusability (low vs. high). On training trials, the match condition was shown co-presented exemplars from the same category, whereas those in the contrast condition were shown co-presented exemplars from different categories; the control condition was shown individual exemplars. Participants learned artificial categories in a mixed design with comparison type manipulated between subjects and confusability within subjects. Learning was assessed via training performance, embedded endorsement, and posttest endorsement measures. Across all measures, contrast outperformed match, whereas control performed comparably to contrast. Notably, even with fewer exposures, single-item presentation still outperformed match presentation, suggesting that co-presenting exemplars does not always lead to better learning.