Natural Selection and Social Theory: Selected Papers of Robert Trivers Robert Trivers OXFORD UNIVERSITY PRESS Natural Selection and Social Theory Evolution and Cognition General Editor: Stephen Stich, Rutgers University Published in the Series Simple Heuristics That Make Us Smart Gerd Gigerenzer, Peter M. Todd, and the ABC Research Group Adaptive Thinking Gerd Gigerenzer Natural Selection and Social Theory: Selected Papers of Robert Trivers Robert Trivers Natural Selection and Social Theory ሆህሄ Selected Papers of Robert Trivers Robert Trivers 1 2002 3 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 Sa˜o Paulo Shanghai Singapore Taipei Tokyo Toronto and an associated company in Berlin Copyright ᭧ 2002 by Oxford University Press, Inc. Published by Oxford University Press, Inc. 198 Madison Avenue, New York, New York 10016 www.oup.com Oxford is a registered trademark of Oxford University Press 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, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Library of Congress Cataloging-in-Publication Data Trivers, Robert. Natural selection and social theory : selected papers of Robert Trivers / by Robert Trivers. p. cm.—(Evolution and cognition) A collection of 10 papers, 5 published in scholarly journals between 1971–1976 and 5 between 1982–2000. Reciprocal altruism—Parental investment and reproductive success—The Trivers-Willard effect—Parent-offspring conflict—Haplodiploidy and the social insects —Size and reproductive success in a lizard—Selecting good genes for daughters— Self-deception in service of deceit—Genomic imprinting—Fluctuating asymmetry and 2nd:4th digit ratio in children. Includes bibliographical references and index. ISBN 0-19-513061-8; 0-19-513062-6 (pbk.) 1. Sociobiology. 2. Evolution (Biology) 3. Social evolution in animals. I. Title. II. Series. GN365.9.T762002 304.5—dc21 2001036767 135798642 Printed in the United States of America on acid free paper For my mother, Mildred Raynolds Trivers, author of seven children and seven books of poetry, born July 4, 1912 with love This page intentionally left blank PREFACE This book is a collection of some of my scientific papers, along with accounts of how they were written and short postscripts that attempt to bring the reader up-to-date. I have naturally concentrated on my early papers, the five between 1971 and 1976 that had such a strong influence. In addition to these I have included an empirical paper on lizard size and reproductive success. I have also included a paper (with Jon Seger) showing a bias in female choice toward the interests of daughters, a widely neglected paper that I hope this volume will help resurrect. My thinking on self-deception is scattered in various places, including chapter 16 of my book Social Evo- lution. Here I reproduce a paper with Huey Newton analyzing the contri- bution of self-deception to the crash of an airplane, along with a paper just published that summarizes my current understanding of the subject. Since finishing my book on Social Evolution in 1985, I have largely been occupied trying to understand the genetics and evolution of selfish genetic elements, a vast subject from which I reproduce here only a chapter with Austin Burt on genomic imprinting, itself one of the most interesting discoveries in mammalian genetics in the past twenty years. I close with a brief summary of the results of the only long-term study of fluctuating asymmetry (and the 2nd : 4th digit ratio) in humans. The postscripts are meant to lead the reader to some useful work published after the paper itself. I have not kept up in depth with many of these topics, but when I know of important work I try to draw the reader’s attention to it, and I also try to give a set of recent references that can quickly lead the reader to the larger subject. Having said this, I must emphasize that with modern computer-driven search engines (such as Web of Science) the interested reader has only to find the “cited reference search” and type in the reference to my paper, and the computer will spew out very recent references on the topic. viii PREFACE Acknowledgments This book was completed under a John Simon Guggenheim Memorial Fel- lowship, as well a Smithkline-Beecham Fellowship at the School of Law at Arizona State University. I am most grateful for these fellowships. I am also grateful to the Ann and Gordon Getty Foundation and the Biosocial Re- search Foundation for support of my work. I thank my editor, Kirk Jensen, for his continual encouragement and help. I thank Amy Jacobson for a truly outstanding copyediting of the entire manuscript. I thank the publishers for permission to reproduce the copyrighted material listed below: Chapter 1: Trivers, Robert L. 1971. The evolution of reciprocal altruism. The Quarterly Review of Biology 46(Mar.): 35–57. Chapter 2: Trivers, Robert L. 1972. Parental investment and sexual se- lection. In Sexual Selection and the Descent of Man 1871–1971, ed. Bernard Campbell, 136–179. Chicago: Aldine Publishing Company. Chapter 3: Trivers, Robert L., and Dan E. Willard. 1973. Natural selec- tion of parental ability to vary the sex ratio of offspring. Science 179(Jan.): 90–92. Chapter 4: Trivers, Robert L. 1974. Parent–offspring conflict. American Zoologist 14: 249–264. Chapter 5: Trivers, Robert L., and Hope Hare. 1976. Haplodiploidy and the evolution of the social insects: The unusual traits of the social insects are uniquely explained by Hamilton’s kinship theory. Science 191(Jan.): 249–263. Chapter 6: Trivers, Robert L. 1976. Sexual selection and resource- accruing abilities in Anolis garmani. Evolution 30(Jul.): 253–269. Chapter 7: Seger, Jon, and Robert Trivers. 1986. Asymmetry in the evo- lution of female mating preferences. Nature 319: 771–773. Chapter 8: Trivers, Robert, and Huey P. Newton. 1982. The crash of Flight 90: Doomed by self-deception? Science Digest (Nov.): 66–67, 111. Trivers, Robert. 2000. The elements of a scientific theory of self-deception. Annals of the New York Academy of Sciences 907(Apr.): 114–131. Chapter 9: Burt, Austin, and Robert Trivers. 1998. Genetic conflicts in genomic imprinting. Proceedings of the Royal Society of London (B) 265: 2393–2397. Chapter 10: Manning, J. T., R. L. Trivers, R. Thornhill, and D. Singh. 2000. The 2nd : 4th digit ratio and asymmetry of hand performance in Ja- maican children. Laterality 5(2): 121–132. CONTENTS 1. Reciprocal altruism, 3 2. Parental investment and reproductive success, 56 3. The Trivers-Willard effect, 111 4. Parent–offspring conflict, 123 5. Haplodiploidy and the social insects, 154 6. Size and reproductive success in a lizard, 207 7. Selecting good genes for daughters, 241 8. Self-deception in service of deceit, 255 9. Genomic imprinting, 294 10. Fluctuating asymmetry and the 2nd : 4th digit ratio in children, 309 References, 329 Index, 335 This page intentionally left blank Natural Selection and Social Theory This page intentionally left blank 1 RECIPROCAL ALTRUISM It was the spring semester of 1969 and the population geneticist Richard Lewontin had come to Harvard to deliver a talk on a new methodology that promised to revolutionize the field of population genetics. Lewontin was then at nearly the height of his powers, and 250 people, myself included, were crammed into a lecture hall to hear his eagerly anticipated talk. It was my devout wish that he would fall flat on his face. The reason for this is that I had just been introduced to him by E. O. Wilson, Harvard’s fabulous social insect man, at the tea preceding his talk. Lewontin had at once proceeded to dump on me, a mere first-year graduate student. The previous fall I had written a very negative paper attacking the work of two theoretical ecologists, Robert MacArthur and Richard Levins, and Lewontin was a personal friend of Levins at the University of Chicago. A fellow graduate student had carried the manuscript to a conference and allowed someone to make a photocopy, and like a true pathogen it had spread rapidly around the globe. I even received a glowing letter from a well-known Australian ecologist. When I realized the manuscript had gone public I sent copies to MacArthur and Levins. MacArthur wrote a very nice letter in return; Levins did not deign to reply. Lewontin began by saying, “Oh yes, you’re the fellow that wrote that wrong-headed paper on Mac- Arthur and Levins,” and dismissed it in a few sentences. He pointed to some equations on the board that he had apparently shown to Ed Wilson and told me that one of my criticism was easily handled if you used these equations. As Wilson squinted myopically toward the board (and with only one good eye at that!) I thought I could see at a glance that Lewontin had merely complexified the problem—thereby hiding the error more deeply—but that the same problem remained in his formulation as in the work of Levins himself. I have learned in my life that my memory of what I regard as odious 3 4 NATURAL SELECTION AND SOCIAL THEORY behavior is always more negative than the actual behavior itself, but in any case Lewontin had a somewhat arrogant and condescending style, and his treatment of me, I later learned, was by no means out of character. I took an immediate dislike to him. Ernst Mayr, Harvard’s venerated evolutionary biologist, introduced Le- wontin at the talk, and I remember Lewontin thanked “Ernst” for his intro- duction, which drew an almost audible gasp from the audience, who had never before heard Professor Mayr referred to in public by only his first name.