Teaching by Examples: Implications for the Process of Category Acquisition

A new paradigm, the "teaching-by-examples" paradigm, was used to shed new light on the process of category acquisition. In four experiments (n = 90, 90, 115, 117), manipulating the variables of category structure, status of non-target category, learning mode, and teaching mode, participants first learned a category and then taught it to someone else. High agreement between participants on the teaching sequences was found across conditions, and a typical sequence was identified for each category structure. The typical participant-produced sequences started with several ideal positive cases, followed by an ideal negative case and then borderline cases. The efficiency of such sequences for teaching was tested in another experiment (n = 60), in which they were compared with sequences emphasizing category borders and sequences emphasizing each dimension separately. The typical participant-produced sequences induced the most efficient learning. It is proposed that the pattern of performance may provide a rich source of data for testing and fine-tuning models of category acquisition.