Brain and Culture
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49497WexlerREV 3/27/06 4:33 AM Page 1 cognitive science has often been associated with violent conflict. Based on “Bruce Wexler’s Brain and Culture is a major “The emerging field of social neuroscience and culture brain its new analysis of the relationship between individuals achievement, touching the deepest biological receives a tremendous boost from the publi- brain and culture and their environments, Brain and Culture argues that peo- and human issues and framing them in verifi- cation of Bruce Wexler’s Brain and Culture. brain and culture ple will fight for control of the public idea space because able terms. A very powerful and very impor- The brain, he argues, does not merely dictate NEUROBIOLOGY, IDEOLOGY, AND SOCIAL CHANGE they do not like to live within someone else’s symbolic or tant book.” how we respond to changes in the environ- cultural environment, or to have their children adopt for- —Oliver Sacks, author of The Man Who ment, but is itself shaped through interaction eign customs. This neurobiological antagonism to differ- Mistook His Wife for a Hat with the social world. In cogent and convinc- BRUCE E. WEXLER ence may be an important factor in sectarian violence ing writing, Wexler argues that social rela- around the globe today. “A pioneering and bold effort to construct a tions, even culture and ideology, involve a Brain and Culture reviews extensive neuroscience, psycho- bridge between scientific findings about the neurobiology that can now be explored logical, social science, and historical research to offer a Bruce E. Wexler is Professor of Psychiatry at Yale Medical brain and the diversity, strengths, and fragili- through the tools of modern neuroscience. new view of the relationship between people and their School and Director of the Neurocognitive Research ties of human cultures. This book helps to Through psychiatric case studies, historical environments. Our brains require sensory input from the Laboratory at the Connecticut Mental Health Center. ‘center’ a pendulum that has in recent years analysis, experiments with various species, environment to develop normally, and that input shapes swung too far in the direction of biological and human neuroimaging, he reveals that dis- the brain systems necessary for perception, memory, and determinism.” tinctions between mind and brain, self and thinking. Environmental shaping of the brain is much —Howard Gardner, author of Multiple environment, and individual and culture can greater in people than in other animals and, more impor- A Bradford Book Intelligences and Changing Minds no longer be understood in traditional ways. tantly, we shape the environment that shapes our brains This book is essential for anyone who wants a to an extent without precedent. Even the structure and “There can’t be many authors bold enough to deeper understanding of the connections function of DNA that codes for brain proteins are changed speak authoritatively of brain structures, the between the neurological and social worlds.” by early life experience. Through these processes our Soviet psychologist Lev Vygotsky, and the —Peter Salovey, Chris Argyris Professor of brains shape themselves to the individual cultural and Albigensian heresy. Wexler demonstrates an Psychology and Dean of Yale College, Yale interpersonal environments in which we are reared. It is impressive intellectual range as he weaves a University our nature to be nurtured. rich tapestry of the interactions of neuronal By early adulthood, neuroplasticity is much reduced, systems and the sociocultural environment in established neuro-psychological structures become self- the development of humans’ uniquely adapt- maintaining, and we act on the environment in large part able brains and minds.” to create sensory input that matches the established —Steven Rose, The Open University and internal structures. Research shows that we affiliate with University College London like-minded individuals, ignore, forget, and discredit infor- mation that does not match our beliefs, and like things WEXLER more simply because they are familiar. At certain times in life--when a spouse dies, or when people move to a foreign country, for example--environmental changes exceed the NEUROBIOLOGY, IDEOLOGY, AND SOCIAL CHANGE ability of such mechanisms to maintain internal-external consonance. When this happens, our ability to function and even our health are compromised, and a difficult and lengthy restructuring of neural circuits and psychological schema is necessary. 0-262-23248-0 For most of human history people lived in communi- ties separate enough to develop distinct languages, over The MIT Press 5000 of which are still spoken today. In recent centuries, Massachusetts Institute of Technology ,!7IA2G2-CDCEIH!:T;K;K;K;K contact among cultures has increased dramatically and Cambridge, Massachusetts 02142 http://mitpress.mit.edu BRUCE E. WEXLER (continued on back flap) Brain and Culture Brain and Culture Neurobiology, Ideology, and Social Change Bruce E. Wexler A Bradford Book The MIT Press Cambridge, Massachusetts London, England © 2006 Massachusetts Institute of Technology All rights reserved. No part of this book may be reproduced in any form by any electronic or mechanical means (including photocopying, recording, or information storage and retrieval) without permission in writing from the publisher. MIT Press books may be purchased at special quantity discounts for business or sales promotional use. For information, please email [email protected] or write to Special Sales Department, The MIT Press, 55 Hayward Street, Cambridge, MA 02142. This book was set in Stone Sans and Stone Serif by SNP Best-set Typesetter Ltd., Hong Kong and was printed and bound in the United States of America. Library of Congress Cataloging-in-Publication Data Wexler, Bruce E. Brain and culture : neurobiology, ideology, and social change / by Bruce E. Wexler. p. cm. “A Bradford book.” Includes bibliographical references (p. ) and index. ISBN 0-262-23248-0 (alk. paper) 1. Social change—Psychological aspects. 2. Culture—Psychological aspects. 3. Neurobiology–Social aspects. I. Title. HM831.W48 2006 612.8—dc22 2005056284 10 9 8 7 6 5 4 3 2 1 In memory of my father, Jack Wexler, whose journey I continue. Contents Acknowledgments ix Introduction 1 1 Background: Some Basic Facts about the Human Brain 19 I Transgenerational Shaping of Human Brain Function 37 2 Effects of Sensory Deprivation and Sensory Enrichment on Brain Structure and Function 39 3 Effects of the Social Environment on Brain Structure and Function 85 II The Neurobiology of Ideology 139 4 Self-Preservation and the Difficulty of Change in Adulthood 141 5 The Meeting of Cultures 183 Epilogue 233 References 255 Index 299 Y2 Acknowledgments I wish to thank all my teachers for making this book possible. Among them, my family has been particularly important as teachers, companions, and supporters: my parents, Ruth and Jack, my wife, Laura, my son, Thomas, and my daughter, Rebecca, my brothers, Richard and Steven, and their wives and children. I offer special thanks to some of my academic teachers who shaped and enabled my thought at critical times and in particularly important ways: Rogers Albritton, Oliver Sacks, Marcel Kinsbourne, and Robert Shulman. I am grateful to Tom Stone, my editor at MIT Press, for seeing the value in the manu- script and then skillfully piloting it through the narrows, and to Ruth Haas, who copy edited with broad knowledge and valu- able suggestions. Brain and Culture Introduction Knowledge about the ways our minds and brains work has increased dramatically over the past 100 years. Some of this new knowledge comes from studies of other animals with which we share aspects of behavior. Other information comes from new methods of observation and experimental study of human beings, both as individuals and in groups. Each body of knowl- edge has its own methods of inquiry and language to collect and describe information, and each represents distinct commu- nities of investigators and theoreticians. Despite this, the differ- ent bodies of knowledge are assumed to be fundamentally linked. Neurological and psychological function are two sides of a coin, and different aspects of each are joined in the organic wholeness of the individual. In this book, I explore links among several of the major bodies of new knowledge about human neurological and psychological function. Two things are partic- ularly striking about these links. First, the links among bodies of knowledge that heretofore have remained largely separate are straightforward. Second, important new aspects of human individual and social behavior become apparent through these links. 2 Introduction The first sets of knowledge I consider relate to the period of development between birth and early adulthood. During this period the brain depends upon sensory stimulation to develop physically, and the functional and structural organization of the brain is strongly influenced by the nature of that stimulation. The period of brain maturation and associated environmental influence is much longer in people than in other animals, and the parts of the brain that most distinguish the human brain from those of other primates are the last to mature and subject the longest to shaping by the environment. Stimulation from other members of the species (e.g., parents, siblings, and peers) is a particularly important factor in shaping neuropsychological development. Primate infants seek out maternal stimulation, and numerous studies have demonstrated that such stimulation is essential for the physiological stability and physical growth of the infant. Research on the neurobiology of social bonding and attach- ment demonstrated the evolutionary appearance of new mecha- nisms to support such behaviors in mammals. Research in molecular genetics identified mechanisms through which maternal stimulation of infants creates lasting changes in the structure and configuration of DNA that then influence the level of activity of specific genes throughout the individual’s life. Research on human parenting has documented the remarkable degree to which the mother and her infant become an inte- grated dyadic unit in which the infant develops.