How do people learn, revise, and reason about everyday biological, physics, artifact, and social categories? The presence and structure of causal knowledge about the interrelations among the properties associated with novel, but plausible everyday categories will be studied in five behavioral experiments. At the same time, in a factorial design, the statistical structure of the properties associated with members of the categories will be manipulated. The experimental manipulations vary the presence and structure of this background information: participants will be tutored on information organized into "common-cause," "common effect," "linear chain," or "no inter-relationship" schemas. Then the effects of this recently learned background information on learning, classification, inductive inferences and similarity judgments will be measured. The impact of information that disconfirms prior knowledge of these concepts will also be studied, as a function of the participant's beliefs about causal structure of the categories. The results will advance our theoretical and practical knowledge about category representation and category-based reasoning. The research addresses many philosophical and psychological questions about everyday knowledge and reasoning. The results are directly relevant to science education: How do we learn general, background scientific information and then relate that knowledge to specific scientific concepts.
