Instance Frequency, Categorization, and the Modulating Effect of Experience

Three experiments explored the role of instance frequency on categorization, where the variables of category size, old-new similarity, and degree of learning were varied. Following learning, subjects received a transfer task that included the category prototype, new instances, and new instances that had a manipulated similarity relationship to training instances that were differentially familiarized. The results indicated that instance frequency was relatively unimportant in influencing transfer, regardless of category size (3, 20), when original training was taken to nearerrorless performance (Experiments 1 and 2). However, instance frequency emerged as an important variable at early and intermediate levels of learning for each category size (Experiment 3). The results of a quantitative model suggest that instance frequency is inversely related to the emergent influences of the category prototype.