Categorization and causal reasoning are my two main areas of research interest. Concepts are the building blocks of our thinking. However, it is still controversial how concepts are represented in the mind and why we have the categories that we have. For example, why is it that we have such concepts as dogs and unicorns but not such concepts as red pointy things? I examine how people create and learn new concepts, taking a Cognitive Science approach. Traditional theories on concepts have assumed that concepts are coherent because members in the same category are similar to each other. In contrast, I argue that conceptual representations are like scientific theories in that features of concepts (e.g., "have legs" "jump" in dog category) are causally related to each other. In order to fully develop this so-called theory-based or explanation-based approach to categorization, I have also studied how we construct causal explanations and identify causes of events. My recent research concerns the role of causal explanations in categorization. For example, causal relations among features of a concept can determine the centrality of features. Causal structures within a concept can specify how people make inferences about other concepts. These studies have direct implications for how we form and change stereotypes (i.e., a special case of person categories), how clinicians use clinical categories when diagnosing patients, and how experts' and novices' categorization processes differ as a function of causal background knowledge.
Luhmann, C. C., & Ahn, W. (2007). BUCKLE: A model of unobserved cause learning. Psychological Review. 114(3), 657-677
Marsh, J. K. & Ahn, W. (2009). Spontaneous assimilation of continuous values and temporal information in causal induction. Journal of Experimental Psychology: Learning, Memory, and Cognition, 35, 334-352.
Rottman, B. M., Ahn, W., Sanislow, C. A., & Kim, N. S. (2009). Can Clinicians Recognize DSM-IV Personality Disorders from Five-Factor Model Descriptions of Patient Cases? The American Journal of Psychiatry, 166, 427-433.
Ahn, W., Proctor, C. C., & Flanagan, E. H. (2009). Mental health clinicians’ beliefs about the biological, psychological, and environmental bases of mental disorders. Cognitive Science, 33, 147-182.
Rottman, B. M., & Ahn, W. (2009). Causal Learning about Tolerance and Sensitization. Psychonomic Bulletin & Review. 16, 1043-1049