IMPULSE david lewis Impulse Why We Do What We Do Without Knowing Why We Do It The Belknap Press of Harvard University Press Cambridge, Massachusetts 2013 Copyright © David Lewis, 2013 All rights reserved Printed in the United States of America First published in Great Britain in 2013 by Random House Books First Harvard University Press edition, 2013 Typeset by Palimpsest Book Production Limited, Falkirk, Stirlingshire Library of Congress Cataloging-in-Publication Data Lewis, David, 1942– Impulse : why we do what we do without knowing why we do it / David Lewis. — First Harvard University Press edition. pages cm Includes bibliographical references and index. ISBN 978-0-674-72549-2 (cloth : alk. paper) 1. Impulse. I. Title. BF575.I46L49 2013 153.4—dc23 2013012499 To S. M. with my love and gratitude Contents Acknowledgements xi Introduction xiii Chapter 1 The Impulse That Saved My Life 1 Chapter 2 Impulses and Your Zombie Brain 11 Chapter 3 Inside the Impulsive Brain 27 Chapter 4 The Teenage Brain – A Work in Progress 43 Chapter 5 Impulse and the Senses 56 Chapter 6 The Power of the Visual 72 Chapter 7 Impulses and the Risk-Taking Personality 88 Chapter 8 The Love Impulse – ‘It Only Takes a Moment’ 109 Chapter 9 The Overeating Impulse – Digging Our Graves 132 with Our Teeth Chapter 10 The Buying Impulse – The How and Why of 149 What We Buy Chapter 11 The Imitation Impulse – ‘A Beautiful Place 162 to Die’ Chapter 12 Deplete Us Not Into Temptation 179 Afterword Free Will Is a Grand Illusion 198 Notes and References 205 Bibliography 249 Index 297 ‘Instinct leads, intelligence does but follow.’ William James, The Varieties of Religious Experience: A Study in Human Nature, 1902. Acknowledgements Many people have assisted me in writing this book, and I am especially grateful to those members of the Impulse Research Group for their support and invaluable contribution. My special thanks to Dr John Storey for his medical insights and valuable comments on early drafts of the text. I would like to thank my colleagues at Mindlab International, Joe Hilling MSc, Director of Data Analysis, and Duncan Smith, managing director, for their assistance. Also my thanks to neuroscientist Charlie Rose for his work on the references and critique of the text. Steven Matthews has, as always, been diligent in reading and commenting on the text. I extend my warmest thanks to Dr Margaret Yufera-Leitch of the University of Calgary, one of the world’s foremost experts on obesity, whose contribution to the chapter on impulsive eating was significant and important. I am most grateful to Coastguard station chief Don Ellis for his insights into the minds of suicides, knowl- edge gained by often dangerous experience in recovering the bodies of those who were successful and talking others to safety. My thanks also go to Dr Sean Kelly for his valuable assistance. Finally, I am most grateful to Nigel Wilcockson and Sophie Lazar, my editors at Random House, for their invaluable and essential contributions to the shaping of the book. Where necessary, names and personal details in the case histories cited have been changed for reasons of confidentiality and to protect privacy. xii impulse Copyright acknowledgements I would like to thank Dr Hannah Faye Chua for permission to use two images from ‘How we See it: Culturally Different Eye Movement Patterns Over Visual Scenes’ from the article by Boland, Chua, and Nisbett (2005). In Rayner, K., Shen, D., Bai, X., Yan, G. (Eds.) Cognitive and Cultural Influences on Eye Movements. Tianjin, China: People’s Press/Psychology Press, pages 363–378. Also I am most grateful to Dr Richard Russell, Assistant Professor of Psychology at Gettysburg College, for kindly allowing me to use two photographs from his excellent paper ‘A sex difference in facial contrast and its exaggeration by cosmetics’, which appeared in the 2009 issue of Perception. Thanks to Meg Bury of the explOratorium in San Francisco for permission to use a photograph of the Ames Room which forms part of their permanent exhibition. To Dr Russell Swerdlow, co-author of the 2003 Archives of Neurology paper: ‘Right orbitofrontal tumor with pedophilia symptom and constructional apraxia sign’, for his kindly assistance. My thanks go to artist Terry Ayling for creating the line and tone illustrations and to Norman Clark for constructing a model of the Ames Room used in my research. The images on page 81 are reproduced by kind permission of: Figure 1: The Thinker, 1880-81 (bronze), Rodin, Auguste (1840-1917) / Burrell Collection, Glasgow, Scotland / © Culture and Sport Glasgow (Museums) / The Bridgeman Art Library. Figure 2: Discobolus, copy of a Greek original (plaster) (b/w photo), Myron (fl.c.450 BC) (after) / Museo Nazionale Romano, Rome, Italy / Alinari / The Bridgeman Art Library. The images of female and male models on page 116 are reproduced courtesy of Bigstockphoto. com. Introduction As I write these words, my head is watching me from across the room. Every so often the eyes – a colour match for my own – blink. From time to time the mouth silently opens and closes. Created from a life cast that involved pouring gloopy blue resin all over my head and shoulders, while I breathed through straws stuck up each nostril, it is a perfect replica. Perfect, that is, save for one rather sobering difference. While I have aged, my second head, created more than a decade ago, remains – like some three-dimensional Dorian Gray in reverse – youthful. It still has a full head of hair – each one individually and painstak- ingly inserted by hand – while mine is fast receding. Its brow is smooth while mine is furrowed. An even more important difference is that you can lift the top of the head of my doppelgänger and remove the brain. Indeed I often tell people I originally had it made as an attention-grabbing lecture aid for teaching neuropsychology. This, at least, is the explanation I usually offer when asked why on earth I invested so much time and hard-earned cash in such a bizarre acquisition. In truth it is really a justification for what was an irrational and absurd impulse purchase. A purchase which I can only explain away, as is the case with most impulsive acts, by saying it seemed like a good idea at the time! While the impulse that led me to have a second head created was one of my more expensive, it was by no means my most life- changing. Of these there have, so far, been three. Two altered the course of my life completely while the third, which I describe in Chapter 1, saved it. xiv impulse My first life-transforming impulse occurred when I was 21 and browsing in a second-hand bookshop on London’s Charing Cross Road. Until that epiphany, my aim had been to qualify as a medical doctor. When I was ten my parents, knowing I had a great interest in biology, gave me a proper grown-up laboratory microscope. For the next eight years I spent much of my free time dissecting everything from road kill to sheep’s eyes and ox hearts to pig brains obtained from our friendly local butcher. To record my dissections I learned how to take photographs and soon expanded my photographic interests to record local news events, selling the pictures to local newspapers to help finance my science studies. In time I was accepted into medical school and started working to achieve my lifetime’s ambition. Eighteen months into my medical studies, wandering aimlessly around that second-hand bookshop, I chanced upon a copy of People I Have Shot by James Jarché, one of Fleet Street’s earliest press photographers. Jarché’s life story fascinated me and rekindled my interest in photography. I spent half the night reading it and, the following morning, hunched over a formaldehyde-soaked limb in the dissecting room, decided on an impulse to give up medicine and study photography instead. The next afternoon I applied for and was given a place on a three-year photography course at the then Regent Street Polytechnic School of Photography, now part of the University of Westminster. When the course finished I moved first to Paris and then back to London to work as a photojournalist for magazines such as Paris Match, Stern, Oggi and Life. It was a career I pursued with interest and enjoyment for some years until changing course for the second time. Once again on an impulse that occurred at precisely 4.30 on the afternoon of 23 December 1976. A few weeks earlier, a meeting with a clinical psychologist, whose work was the subject of a magazine assignment, opened my eyes to the fascinating and introduction xv important discipline of psychology. While drinking a cup of tea in the picture agency’s Fleet Street offices I took a spur-of-the- moment decision to return to university and read psychology. That impulse resulted in a complete change of direction in my life and a career that still fascinates me more than three decades later. It has also led to my long-standing professional interest in the psychology of ‘impulsivity’, in trying to make sense of those spur-of-the-moment decisions that often change our lives. To understand our behaviour in all its many and varied facets, it is essential to understand impulses, since these (as I shall explain in Chapter 2) comprise the vast majority of our actions. We all like to regard ourselves as rational human beings. To believe we act only after careful reflection and thoughtful deliberation. The fact is, however, that our actions are mindless far more often than they are mindful: the product not of logic and reason but of habits driven by emotions.