The Rationality Quotient: Toward a Test of Rational Thinking

by Keith E. Stanovich, Richard F. West, Maggie E. Toplak

How to assess critical aspects of cognitive functioning that are not measured by IQ rational thinking skills. Why are we surprised when smart people act foolishly? Smart people do foolish things all the time. Misjudgments and bad decisions by highly educated bankers and money managers, for example, brought us the financial crisis of 2008. Smart people do foolish things because intelligence is not the same as the capacity for rational thinking. The Rationality Quotient explains that these two traits, often (and incorrectly) thought of as one, refer to different cognitive functions. The standard IQ test, the authors argue, doesn't measure any of the broad components of rationality—adaptive responding, good judgment, and good decision making. The authors show that rational thinking, like intelligence, is a measurable cognitive competence. Drawing on theoretical work and empirical research from the last two decades, they present the first prototype for an assessment of rational thinking analogous to the IQ the CART (Comprehensive Assessment of Rational Thinking). The authors describe the theoretical underpinnings of the CART, distinguishing the algorithmic mind from the reflective mind. They discuss the logic of the tasks used to measure cognitive biases, and they develop a unique typology of thinking errors. The Rationality Quotient explains the components of rational thought assessed by the CART, including probabilistic and scientific reasoning; the avoidance of “miserly” information processing; and the knowledge structures needed for rational thinking. Finally, the authors discuss studies of the CART and the social and practical implications of such a test. An appendix offers sample items from the test.

Genres: Psychology, Science, Nonfiction, Philosophy

478 pages, Paperback

Published February 9, 2018

About the author

Keith E. Stanovich is Emeritus Professor of Applied Psychology and Human Development at the University of Toronto and former Canada Research Chair of Applied Cognitive Science. He is the author of over 200 scientific articles and seven books. He received his BA degree in psychology from Ohio State University in 1973 and his PhD in psychology from the University of Michigan in 1977.

Reviews

[Yuliy L · Rating 4 out of 5]

Stanovich and West wrote about testing different aspects of rationality aside from intelligence tests in the past books, “What Intelligence Tests Miss”, “Rationality and the Reflective Mind” and in a number of articles. In this book they report how they created a test to measure different aspects within their model of a rational mind.

They start with their model of thinking and tell the difference between intelligence and rationality. They also describe their own construct of rationality, which they use to to define different aspects. So their test, the Comprehensive Assessment of Rational Thinking (CART) consist of different components to test these aspects.

In the same time they start with the strong sense of rationality, as a distance from the optimum defined by a normative model. It means that rationality has different degrees and can be measured.
They also study correlation between results on the different parts of the test. The test itself is long and it takes several hours to take it, as it has twenty separate subtests. So it may be an interesting and practically useful result that they found a high correlation with a shorter, 38-question version of the test. The shorter test consists of the two subtests, the Probabilistic and Statistical Reasoning and the Scientific Reasoning.

The book also have examples of different test questions from different subtests, they give a good impression of what the whole test looks like. In the same time there are not enough questions to test someone and only authors have the whole set. I assume that the test will be evaluated and researched some more before it would be accessible for general public.

I can add that it is a scientific study, not a popular-science book, so you better to have some background knowledge in this area or you should be prepared to check other books and articles during the reading.

I can recommend this book if you want to know in details how the rationality can be tested and measured. The book also gives some ideas how people can improve their rational thinking. In the same time you can check another book, “Rationality and the Reflective Mind”, to find how Stanovich’s model of the mind works and how you can improve its working.

[Matt Danner · Rating 3 out of 5]

A tough one to plow through. I read this for research on a paper, and I only really understood it because I had already read Stanovich's previous writing, including What Intelligence Tests Miss. This is probably a good reference for professionals, not a good read for the beach.