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Simple Heuristics That Make Us Smart

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Simple Heuristics That Make Us Smart

Oxford UP,

15 min read
10 take-aways
Audio & text

What's inside?

With the right heuristic – or rule of thumb – your quick decisions may turn out better than your slow analytical choices.

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Editorial Rating



  • Innovative


People aren’t computers. Human beings live in a real world of scarcity and constraint. Even though time and information may be scarce, human beings must make high-stakes decisions. Probability and logic offer models for the thought process of choosing between alternatives, but decision makers often do not have enough hours, data and skill to use these sophisticated approaches. Fortunately, some rough and ready cognitive shortcuts perform as well as or better than the most elaborately sophisticated models - at least in the real world context of limited information and time. Working with the ABC Research Group, authors Gerd Gigerenzer and Peter M. Todd explore some of those shortcuts, called "heuristics." They discuss in length and depth a series of experiments that demonstrate the value of heuristics. This is not light reading. It requires a level of comfort with academic style, mathematics and symbolic logic. Readers unfamiliar with cognition literature may find it a struggle - but believes that those who persevere will find enough new insight to make the effort worthwhile.


Why Heuristics?

An emergency room doctor faces a difficult decision: a patient has been hurried in who is having a heart attack. The stakes are high. The doctor must determine quickly whether the man is a "low-risk or a high-risk" patient. How can the doctor make a fast decision in these circumstances? After all, one analysis method tests and weighs some 19 separate factors.

Fortunately for the patient, the doctor has a simple decision tree that makes it possible to dispense with the 19-factor analysis. This simple decision tree asks only three questions, allowing the doctor to decide based on three variables: blood pressure, age and presence of sinus tachycardia (sinus rhythm faster than 100 beats per minute). A patient with high blood pressure is high risk. A patient younger than 62.5 years old is low risk. And, an older patient is high risk only if sinus tachycardia is present.

This three-question decision tree is a fast, frugal heuristic that replaces a time-consuming analysis. For purposes of focusing scarce medical resources on high-risk patients in order to save lives, it is much better than a complex, time-consuming approach that makes use of all available...

About the Authors

Gerd Gigerenzer is co-director of the Max Planck Institute and Professor of Psychology at the Freie Universität Berlin. He wrote Calculated Risks: How To Know When Numbers Deceive You. The book’s German translation won the Scientific Book of the Year Prize in 2002. Dr. Peter M. Todd is Professor of Cognitive Science and Informatics at Indiana University. In total, 18 expert authors contributed to this book.

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