Sense and Nonsense: Evolutionary Perspectives on Human Behaviour Kevin N. Laland Gillian R. Brown OXFORD UNIVERSITY PRESS SN-Prelims (i-xii) 3/4/02 12:22 PM Page i Sense and Nonsense SN-Prelims (i-xii) 3/4/02 12:22 PM Page ii This page intentionally left blank SN-Prelims (i-xii) 3/4/02 12:22 PM Page iii Sense and Nonsense Evolutionary Perspectives on Human Behaviour Kevin N. Laland Royal Society University Research Fellow Sub-Department of Animal Behaviour University of Cambridge and Gillian R. Brown Research Scientist Sub-Department of Animal Behaviour University of Cambridge 1 SN-Prelims (i-xii) 3/4/02 12:22 PM Page iv 1 Great Clarendon Street, Oxford OX2 6DP Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide in Oxford New York Auckland Bangkok Buenos Aires Cape Town Chennai Dar es Salaam Delhi Hong Kong Istanbul Karachi Kolkata Kuala Lumpur Madrid Melbourne Mexico City Mumbai Nairobi São Paulo Shanghai Taipei Tokyo Toronto and an associated company in Berlin Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries Published in the United States By Oxford University Press Inc., New York © Kevin N. Laland and Gillian R. Brown, 2002 The moral rights of the authors have been asserted Database right Oxford University Press (maker) First published 2002 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above You must not circulate this book in any other binding or cover and you must impose this same condition on any acquirer A catalogue record for this title is available from the British Library Library of Congress Cataloguing in Publication Data Data available ISBN 0 19 850884 0 (Hbk) 10987654321 Typeset by EXPO Holdings, Malaysia Printed in Great Britain on acid-free paper by T.J. International, Padstow, Cornwall SN-Prelims (i-xii) 3/4/02 12:22 PM Page v Preface Can evolutionary theory help us to understand human behaviour and society? Many evolutionary biologists, anthropologists, and psychologists are optimistic that evo- lutionary principles can be applied to human behaviour, and have offered evolutionary explanations for a wide range of human characteristics, such as homicide, religion, and sex differences in behaviour. Others are sceptical of these interpretations, and stress the effects of learning and cul- ture. They maintain that human beings are too special to study as if they were just another animal—after all, we have complex culture, language, and writing, and we build houses and programme computers. Perhaps both of these stances are right to a degree. Some aspects of our behaviour may be more usefully investigated using the methods of evolutionary biology than others. The challenge for sci- entists will be to determine which facets of humanity are open to this kind of analysis, and to devise definitive tests of any hypotheses concerning our evolutionary legacy. For those of us fascinated by this challenge, knowledge of the diverse methods by which human behaviour is studied from an evolutionary perspective would seem a pre- requisite. In this book, we outline five evolutionary approaches that have been used to investigate human behaviour and characterize their methodologies and assumptions. These approaches are sociobiology, human behavioural ecology, evolutionary psychology, memetics, and gene–culture coevolution. For each, we discuss their SN-Prelims (i-xii) 3/4/02 12:22 PM Page vi vi PREFACE positive features and their limitations and in the final chap- ter we compare their relative merits. Innumerable popular books have already been published that discuss human behaviour and evolution, e.g. The Selfish Gene (Dawkins, 1976), The Rise and Fall of the Third Chimpanzee (Diamond, 1991), Darwin’s Dangerous Idea (Dennett, 1995), How the Mind Works (Pinker, 1997) and The Meme Machine (Blackmore, 1999). Each gives a unique and stimulating view of human nature. However, such books usually take a single viewpoint on human evolution, frequently identifying with a particular school, such as evolutionary psychology or memetics. There have also been academic books published from these different perspec- tives, such as Culture and the Evolutionary Process (Boyd and Richerson, 1985), The Adapted Mind (Barkow et al., 1992), Adaptation and Human Behavior (Cronk et al., 2000) and Darwinizing Culture: the Status of Memetics as a Science (Aunger, 2000). In contrast to these, our book takes a plu- ralistic approach, highlighting how different researchers have divergent views on the best way to use evolutionary theory to study humanity. Heated debates and personal attacks have often ensued. Some of the approaches described will be new to many readers, as the theories on which they are based have generally not made it further than the specialist scientific literature. In presenting these fields we endeavour to translate these methodologies into easily understandable examples, and thereby make accessi- ble new perspectives on how human behaviour and culture can be interpreted. In writing this book, we pursue three goals. First, like Eric Alden Smith and colleagues (Smith et al., 2001), we see a need for ‘a guide for the perplexed’ for those of us who have SN-Prelims (i-xii) 3/4/02 12:22 PM Page vii PREFACE vii struggled to understand the plethora of confusing terms and apparent differences of opinion and approach in the use of evolutionary theory to study human behaviour. Secondly, in line with a long tradition of researchers based at the Sub-Department of Animal Behaviour at the University of Cambridge, where we work, we believe that research in this domain is best served by a rigorous, self- critical science, and that the study of behaviour requires a broad perspective that incorporates questions such as how behaviour develops over an individual’s lifetime as well as questions about how behaviour evolves. Thirdly, we see great value in pluralism in the use of methodology, and the integration of approaches. We hope to have made a small contribution in each of these regards. This book does not provide an overview of the use of evo- lutionary theory in areas such as economics, law, and litera- ture. We acknowledge the important work in these areas, but would rather maintain the length of the book as it is, and remain within more familiar territory. To those whose research is addressed, we hope that a fair synopsis is provided and are very grateful to all of the experts who have taken the time to discuss their work with us. We have personal views on the relative merits of the five schools of thought described; however, we have attempted to treat each approach evenly by asking leading members in the fields to help us to present their views accurately. Perhaps our profiles of the alternative approaches will highlight to some researchers how the meth- ods may be integrated in the future, as well as draw attention to the conflicts that are yet to be resolved. Of those who cur- rently deny the relevance of biology to the study of human behaviour, we hope that we might perhaps make some con- verts. More realistically, we hope that their scepticism will be SN-Prelims (i-xii) 3/4/02 12:22 PM Page viii viii PREFACE tempered by the realization that not all researchers in this area are genetic determinists, Panglossian adaptationists, or wan- ton biologizers, and that many are prepared to place empha- sis on non-biological and even non-evolutionary explana- tions. Our intention is that this introductory book will be of use to undergraduate and postgraduate students (for example, in zoology, anthropology, and psychology) and to experts on one approach who would like to know more about the other perspectives, but also to lay persons interested in evo- lutionary explanations of human behaviour. We have tried to write the text so that anyone interested in this subject area will find the material easy to comprehend. Our inten- tion is not to provide a textbook review of the whole subject area, but rather to give a taste of the various options. For readers who would like to know more about a particular perspective, further reading is provided at the end of the book. The most enjoyable aspect of writing this book has been the opportunity to interact with many of the leading authorities in this area of research. We have been over- whelmed by the kindness and generosity of those who have discussed their work with us and have commented on chap- ters of the book: we have learned so much from them. We would like to thank the following people for commenting on one or more chapters and for discussing the material in the book: Robert Aunger, Pat Bateson, Gillian Bentley, Susan Blackmore, Monique Borgerhoff Mulder, Robert Boyd, Nicky Clayton, Tim Clutton-Brock, Leda Cosmides, Alan Costall, Nick Davies, Richard Dawkins, Daniel Dennett, Robin Dunbar, Dominic Dwyer, Marc Feldman, Dan Fessler, Jeff Galef, Oliver Goodenough, Russell Gray, SN-Prelims (i-xii) 3/4/02 12:22 PM Page ix PREFACE ix Kristen Hawkes, Robert Hinde, Sarah Blaffer Hrdy, David Hull, Rufus Johnstone, Mark Kirkpatrick, Richard Lewontin, Elizabeth Lloyd, John Maynard Smith, John Odling-Smee, Sally Otto, Henry Plotkin, Peter Richerson, Eric Alden Smith, Elliott Sober, John Tooby, Markus Vinzent, and Ed Wilson.