sense and nonsense evolutionary perspectives on human behaviour jun 2002

Sense and Nonsense: Evolutionary Perspectives on Human Behaviour Kevin N. Laland Gillian R. Brown OXFORD UNIVERSITY PRESS Sense and Nonsense SN-Prelims (i-xii) 3/4/02 12:22 PM Page i SN-Prelims (i-xii) 3/4/02 12:22 PM Page ii This page intentionally left blank 1 Sense and Nonsense 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 Evolutionary Perspectives on Human Behaviour SN-Prelims (i-xii) 3/4/02 12:22 PM Page iii 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 iv 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 Preface SN-Prelims (i-xii) 3/4/02 12:22 PM Page v 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 vi PREFACE SN-Prelims (i-xii) 3/4/02 12:22 PM Page vi 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 vii 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, viii PREFACE SN-Prelims (i-xii) 3/4/02 12:22 PM Page viii 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. We are also particularly grateful to Jeffrey Brown, Dominic Dwyer, Robert Hinde, Claire Laland, Bob Levin, Ed Morrison, and John Odling-Smee for reading the entire book and providing detailed feedback. We would like to thank the members of the Discussion Group at Madingley (Roz Almond, Yfke van Bergen, James Curley, Rachel Day, Tim Fawcett, Will Hoppitt, Jeremy Kendal, Bob Levin, and Liz Pimley), who worked through early drafts of each chapter with us, and provided very valuable input and encouragement. We were helped by comments from Mat Anderson, Martin Daly, Jean Dobel, Richard McElreath, Heather Proctor, and Joan Silk. Thanks also to Martin Baum at OUP and to Sheila Watson of Watson Little Ltd for their advice and guidance. This research was supported by a Royal Society University Research Fellowship to KNL and Medical Research Council funding to GRB. Finally, we are grateful to Ed Wilson and Sarah Blaffer Hrdy for their enthusiastic support and encouragement, the memories of which have kept us going when we thought that we might have bitten off more than we could chew. K.N.L. and G.R.B. March 2002 PREFACE ix SN-Prelims (i-xii) 3/4/02 12:22 PM Page ix [...]... based on a number of key assumptions, and, as we shall see in Chapter 7, they are contentious SENSE AND NONSENSE 19 understanding of human behaviour will only result from us studying human beings as animals developing in a rich social environment and immersed in complex cultural traditions Evolutionary perspectives on human behaviour The history of using evolutionary ideas to interpret human behaviour. .. intentionally left blank Contents         Sense and nonsense 1 A history of evolution and human behaviour 27 Human sociobiology 69 Human behavioural ecology 109 Evolutionary psychology 153 Memetics 197 Gene–culture coevolution 241 Comparing and integrating approaches 287 Further reading 319 References 323 Index 363 This page intentionally left blank CHAPTER 1 Sense and nonsense T he human species... used erroneous evolutionary arguments to argue that socialism was harmful and to justify unrestrained capitalism We also see how evolutionary- minded anthropologists 20 SENSE AND NONSENSE and biologists in the 19th century, confusing evolution with progress, applied the ideas of natural selection to the evolution of human societies and argued that some ‘races’ had reached a higher level of evolution than... major contemporary approaches, human behavioural ecology, evolutionary psychology, 22 SENSE AND NONSENSE memetics, and gene–culture coevolution Almost certainly because of the controversy that surrounded it, few of today’s researchers describe themselves as human sociobiologists’, although there are notable exceptions In Chapter 4, we describe the field of human behavioural ecology that has continued... as an ‘unusual scientist’ who took the middle ground and played a mediating role between the protagonists SENSE AND NONSENSE 7 position At the founding meeting of the Human Behavior and Evolution Society (HBES) in Evanston in 1989, president Bill Hamilton gave an address in which he described scholars interested in the evolutionary basis of human behaviour as ‘a small, besieged group’ (Segerstråle,... the behaviour during the lifetime of the individual The third question addresses the function of the behaviour pattern and examines what advantage it gave our ancestors in the struggle to survive and reproduce The fourth investigates the evo- SENSE AND NONSENSE 11 lutionary history of the behaviour and asks why a particular species is characterized by one trait rather than another Questions of function... several males during one ovarian cycle In the light of these observations of closely related species, numerous evolutionary hypotheses have been proposed to explain what was it about our evolutionary past that led to selection for ovulation in women to be concealed—the function of concealed ovulation For example, Alexander and Noonan (1979) suggested that concealment of ovulation would force a male... of human society, it would be reassuring to have confidence in the claims made in its name In which case, should we not be concerned that some of the world’s leading evolutionary biologists are highly critical of the manner in which fellow academics employ evolution to shed light on human nature? The reality is that evolutionary perspectives on human behaviour frequently incite controversy, even amongst... of ovulation might leave greater numbers of descendants than women with this knowledge, leading to the selection of concealed ovulation We can therefore see a proliferation of ideas regarding the supposed evolutionary history and function of concealed ovulation The problem with all of these hypotheses is that concealed ovulation is probably not a derived trait in human beings (Daly and Wilson, 1983;... of ideas, beliefs, and knowledge that exists in a completely different realm to biology These re- SENSE AND NONSENSE 15 searchers believe culture is the primary influence on human behaviour In contrast, many evolutionary- minded researchers think about culture more broadly as the product of an evolutionary process In many animal species, individuals grow up in an environment that contains other individuals . Sense and Nonsense: Evolutionary Perspectives on Human Behaviour Kevin N. Laland Gillian R. Brown OXFORD UNIVERSITY PRESS Sense and Nonsense SN-Prelims (i-xii) 3/4/02. evolution to shed light on human nature? The reality is that evolutionary perspectives on human behaviour frequently incite controversy, even amongst the scientists themselves. Evolutionary theory. 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