John C. Dunn, BA, Ph.D., is an Emeritus Professor in the School of Psychological Science at the University of Western Australia. Dr Dunn’s research has focused on the application of mathematical models to recognition memory, decision making, reasoning, categorization, and eyewitness testimony. He has published over 100 papers in numerous journals including Psychological Review, Proceedings of the National Academy of Science, and the Journal of Experimental Psychology: Learning, Memory, and Cognition. Michael L. Kalish, M.S., Ph.D., is a Professor in the Department of Psychology at Syracuse University. He has published in numerous journals, including: Psychological Review, Cognitive Science, and several sections of the Journal of Experimental Psychology. Dr. Kalish's research involves describing the cognitive mechanisms responsible for the nature of human learning and memory, with a particular focus on categorization and dimensional attention.