Individual differences in category learning: memorization versus rule abstraction.

Although individual differences in category-learning tasks have been explored, the observed differences have tended to represent different instantiations of general processes (e.g., learners rely upon different cues to develop a rule) and their consequent representations. Additionally, studies have focused largely on participants' categorizations of transfer items to determine the representations that they formed. In the present studies, we used a convergent-measures approach to examine participants' categorizations of transfer items in addition to their self-reported learning orientations and response times on transfer items, and in doing so, we garnered evidence that qualitatively distinct approaches in explicit strategies for category learning (i.e., memorization vs. abstracting an articulable rule) and consequent representations might emerge in a single task. Participants categorized instances that followed a categorization rule (in Study 1, we used a relational rule; in Study 2, an additional task with a single-feature rule). Critically, for both tasks, some transfer items differed from trained instances on only one attribute (but otherwise were perceptually similar), rendering the item a member of the opposing category on the basis of the rule (i.e., termed ambiguous items). Some learners categorized ambiguous items on the basis of perceptual similarity, whereas others categorized them on the basis of an abstracted rule. Self-reported learning orientation (i.e., memorization vs. rule abstraction) predicted categorizations and response times on transfer items. Differences in learning orientations were not associated with performance on other cognitive measures (i.e., working memory capacity and Raven's Advanced Progressive Matrices). This work suggests that individuals may have different predispositions toward memorization versus rule abstraction in a single categorization task.