The Rationality Quotient is a significant advance in the psychology of rationality. It presents the best analysis of cognitive errors in the scientific literature and makes a compelling case for measuring rationality independently of intelligence.”—Daniel Kahneman, Princeton University; winner of the 2002 Nobel Prize in Economics

“The project presented by these authors is staggering in its scale and ambition. This work greatly advances our understanding of the distinction between IQ and rational thinking measures over a wide range of cognitive tasks. It also lays the foundation for a test of rational thinking that includes the essential elements missed by IQ testing. This book is essential reading for educationalists, psychometricians, and cognitive psychologists alike.”—Jonathan Evans, Emeritus Professor of Cognitive Psychology, University of Plymouth

“Trying to determine if The Rationality Quotient was suitable for my graduate seminar, I realized I was totally immersed in the case being argued. The book has the happy quality of being novel, yet synthesizing a respected research tradition. These authors are first-rate scholars and they have produced an unusually erudite work. In the end, I determined it is highly suitable for my seminar, but it is also excellent for less advanced audiences because of its clear and careful exposition.”—Stephen J. Ceci, Helen L. Carr Professor of Developmental Psychology, Cornell University

“This groundbreaking book is the culmination of decades of research on what it means to be rational. Previously, these authors argued that being smart (in the IQ sense) does not mean being rational. In this book, they develop a measure that is to rationality what the IQ test is to intelligence. Rationality, as measured by the CART, is a multidimensional concept that embodies the ability, the inclination, and the knowledge to make good decisions. Meticulously tested with over 4,000 participants, the result is the first genuine ‘gold standard’ of rational thinking. A monumental achievement and a must-read for all who call themselves scholars of reasoning.”—Valerie Thompson, Professor of Psychology, University of Saskatchewan; editor of the journal Thinking & Reasoning

“This volume profoundly challenges the century-old citadel of psychometric intelligence, reconceiving what it is to be smart with a measure of rationality richly grounded in contemporary cognitive science’s dual-process model.”—David N. Perkins, Carl H. Pforzheimer Jr. Research Professor of Teaching and Learning, Harvard Graduate School of Education