Gut Feelings THE INTELLIGENCE OF THE UNCONSCIOUS GERD GIGERENZER VIKING viking Published by the Penguin Group Penguin Group (USA) Inc., 375 Hudson Street, New York, New York 10014, U.S.A. Penguin Group (Canada), 90 Eglinton Avenue East, Suite 700, Toronto, Ontario, Canada M4P 2Y3 (a division of Pearson Penguin Canada Inc.) Penguin Books Ltd, 80 Strand, London WC2R 0RL, England Penguin Ireland, 25 St. Stephen’s Green, Dublin 2, Ireland (a division of Penguin Books Ltd) Penguin Books Australia Ltd, 250 Camberwell Road, Camberwell, Victoria 3124, Australia (a division of Pearson Australia Group Pty Ltd) Penguin Books India Pvt Ltd, 11 Community Centre, Panchsheel Park, New Delhi—110 017, India Penguin Group (NZ), 67 Apollo Drive, Mairangi Bay, Auckland 1311, New Zealand (a division of Pearson New Zealand Ltd) Penguin Books (South Africa) (Pty) Ltd, 24 Sturdee Avenue, Rosebank, Johannesburg 2196, South Africa Penguin Books Ltd, Registered Offices: 80 Strand, London WC2R 0RL, England First published in 2007 by Viking Penguin, a member of Penguin Group (USA) Inc. Copyright © Gerd Gigerenzer, 2007 All rights reserved Illustrations by Jurgen Rossbach library of congress cataloging in publication data Gigerenzer, Gerd. Gut feelings : the intelligence of the unconscious / Gerd Gigerenzer. p. cm. Includes bibliographical references and index. ISBN: 1-4295-3566-0 1. Intuition. I. Title. BF315.5.G54 2007 153.4'4—dc22 2006052810 Set in Dante MT with Frutiger Designed by Daniel Lagin Without limiting the rights under copyright reserved above, no part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of both the copyright owner and the above publisher of this book. The scanning, uploading, and distribution of this book via the Internet or via any other means without the permission of the publisher is illegal and punishable by law. Please purchase only authorized electronic editions and do not participate in or encourage electronic piracy of copy- rightable materials. Your support of the author’s rights is appreciated. In affectionate memory of my mother and her courage, humor, and patience CONTENTS PA RT 1: UNCONSCIOUS INTELLIGENCE 1 1. Gut Feelings 3 2. Less Is (Sometimes) More 20 3. How Intuition Works 40 4. Evolved Brains 54 5. Adapted Minds 74 6. Why Good Intuitions Shouldn’t Be Logical 93 PA RT 2: GUT FEELINGS IN ACTION 105 7. Ever Heard Of ...? 107 8. One Good Reason Is Enough 134 9. Less Is More in Health Care 158 10. Moral Behavior 179 11. Social Instincts 207 Acknowledgments 231 Notes 233 References 251 Index 271 We know more than we can tell. —Michael Polanyi Part 1 UNCONSCIOUS INTELLIGENCE The heart has its reasons of which reason knows nothing. —Blaise Pascal 1 GUT FEELINGS e think of intelligence as a deliberate, conscious activity guided by the laws of logic. Yet much of our mental life Wis unconscious, based on processes alien to logic: gut feelings, or intuitions. We have intuitions about sports, friends, which toothpaste to buy, and other dangerous things. We fall in love, and we sense that the Dow Jones will go up. This book asks: Where do these feelings come from? How do we know? Can following your gut feelings lead to some of the best deci- sions? It seems naive, even ludicrous, to think so. For decades, books on rational decision making, as well as consulting firms, have preached “look before you leap” and “analyze before you act.” Pay attention. Be reflective, deliberate, and analytic. Survey all alternatives, list all pros and cons, and carefully weigh their util- ities by their probabilities, preferably with the aid of a fancy statis- tical software package. Yet this scheme does not describe how actual people—including the authors of these books—reason. A professor from Columbia University was struggling over whether to accept an offer from a rival university or to stay. His colleague took him aside and said, “Just maximize your expected utility—you al- ways write about doing this.” Exasperated, the professor re- sponded, “Come on, this is serious.” 4 GUT FEELINGS From economists to psychologists to John Q. Public, most peo- ple readily accept that the ideal of perfect beings with boundless knowledge and eternal time is unrealistic. Yet, they argue, with- out these bounds, and with more logic, we would make superior choices: we may not consider every angle, but we should. This mes- sage is not what you are going to read in the following pages. With this book, I invite you on a journey into a largely un- known land of rationality, populated by people just like us, who are partially ignorant, whose time is limited and whose future is uncertain. This land is not one many scholars write about. They prefer to describe a land where the sun of enlightenment shines down in beams of logic and probability, whereas the land we are visiting is shrouded in a mist of dim uncertainty. In my story, what seem to be “limitations” of the mind can actually be its strengths. How the mind adapts and economizes by relying on the uncon- scious, on rules of thumb, and on evolved capacities is what Gut Feelings is about. The laws in the real world are puzzlingly differ- ent from those in the logical, idealized world. More information, even more thinking, is not always better, and less can be more. Ready for a glimpse? THE HEART’S CHOICE A close friend of mine (call him Harry) once found himself with two girlfriends, both of whom he loved, desired, and admired. Two, however, were one too many. Confused by contradicting emotions and unable to make up his mind, he recalled what Ben- jamin Franklin had once advised a nephew in a similar situation: April 8, 1779 If you doubt, set down all the Reasons, pro and con, in opposite Columns on a Sheet of Paper, and when you have considered GUT FEELINGS 5 them two or three Days, perform an Operation similar to that in some questions of Algebra; observe what Reasons or Motives in each Column are equal in weight, one to one, one to two, two to three, or the like, and when you have struck out from both Sides all the Equalities, you will see in which column re- mains the Balance. [ ...] This kind of Moral Algebra I have of- ten practiced in important and dubious Concerns, and tho’ it cannot be mathematically exact, I have found it extreamly use- ful. By the way, if you do not learn it, I apprehend you will never be married. I am ever your affectionate Uncle, B. FRANKLIN1 Harry was greatly relieved that a logical formula existed to solve his conflict. So he took his time, wrote down all the impor- tant reasons he could think of, weighed them carefully, and went through the calculation. When he saw the result, something unex- pected happened. An inner voice told him that it wasn’t right. And for the first time, Harry realized that his heart had already decided—against the calculation and in favor of the other girl. The calculus helped to find the solution, but not because of its logic. It brought an unconscious decision to his awareness, based on rea- sons obscure to him. Thankful for the sudden solution but puzzled by the process, Harry asked himself how it was possible to make unconscious choices in contradiction to one’s deliberate reasoning. He was not the first to learn that reasoning can conflict with what we call intuition. Social psychologist Timothy Wilson and his col- leagues once offered posters to two groups of women as a thank- you present for participating in an experiment.2 In one group, each woman simply picked her favorite poster out of a selection of five; in a second group, each was asked to describe her reasons 6 GUT FEELINGS for liking or disliking each poster before choosing one. Interest- ingly, the two groups tended to take different posters home. Four weeks later, they were all asked how much they enjoyed their present. Those who had given reasons were less satisfied and regretted their choice more than those who had not given any. Here and in similar experiments, deliberate thinking about reasons seems to lead to decisions that make us less happy, just as consciously thinking about how to ride a bike or put on a spontaneous smile is not always better than its automatic ver- sion. The unconscious parts of our mind can decide without us—the conscious self—knowing its reasons, or, as in Harry’s case, without being aware that a decision has been made in the first place. But isn’t the capability for self-reflection uniquely human and therefore uniformly beneficial? After all, doesn’t thinking about thinking define human nature? Freud used self-introspection as a therapeutic method, and decision consultants employ modern versions of Franklin’s moral algebra as a rational tool. But the ev- idence suggests that weighing pros and cons does not generally make us happy. In one study, people were asked about various everyday activities such as how to decide which TV programs to watch in the evening and what to buy in a department store. Did they survey all channels, using the remote control to flip back and forth through all TV stations, constantly checking for a bet- ter program? Or did they quickly stop searching and watch a good-enough program? People who reported exhaustive search in shopping and leisure were called maximizers, because they tried hard to get the best.