Matt Ridley

This book is crammed with original ideas—very few of them my own. Science writers become accustomed to the feeling that they are intellectual plagiarists, raiding the minds of those who are too busy to tell the world about their discoveries. There are scores of people who could have written each chapter of my book better than I. My consolation is that few could have written all the chapters.

My role has been to connect the patches of others ' research together into a quilt.

But I remain deeply indebted and grateful to all those whose minds I raided. I have interviewed more than sixty people in the course of researching this book and have never met with anything but courtesy, patience, and infectious curiosity about the world. Many became friends. I am especially grateful to those whom I interviewed repeatedly and at length until I had almost picked their minds clean: Laura Betzig, Napoleon Chagnon, Leda Cosmides, Helena Cronin, Bill Hamilton, Laurence Hurst, Bobbi Low, Andrew Pomiankowski, Don Symons, and John Tooby.

Among those who agreed to interviews in person or by telephone, I would like to thank Richard Alexander, Michael Bailey, Alexandra Basolo, Graham Bell, Paul Bloom, Monique Borgehoff Mulder, Don Brown, Jim Bull, Austin Burt, David Buss, Tim Clutton-Brock, Bruce Ellis, John Endler, Bart Gledhill, David Goldstein, Alan Grafen,

Tim

Guilford,

David

Haig,

Dean

Hamer,

Kristen Hawkes, Elizabeth Hill, Kim Hill, Sarah Hrdy, William Irons, William James, Charles Keckler, Mark Kirkpatrick, Jochen Kumm, Curtis Lively, John Maynard Smith, Matthew Meselson, Geoffrey

::: viii :::

ACKNOWLEDGMENTS

Miller, Anders Moller, Atholl McLachlan, Jeremy Nathans, Magnus Nordborg, Elinor Ostrom, Sarah Otto, Kenneth Oye, Margie Profet, Tom Ray, Michael Ryan, Dev Singh, Robert Smuts, Randy Thornhill, Robert Trivers, Leigh Van Valen, Fred Whitam, George Williams, Margo Wilson, Richard Wrangham, and Marlene Zuk.

My sincere thanks also to those who corresponded with me or sent me their papers and books: Christopher Badcock, Robert Foley, Stephen Frank, Valerie Grant, Toshikazu Hasegawa, Doug Jones, Egbert Leigh, Daniel Perusse, Felicia Pratto, and Edward Tenner.

Other minds I raided more subtly, even surreptitiously.

Among those who have given advice or helped to clear my thoughts in many conversations are Alun Anderson, Robin Baker, Horace Barlow, Jack Beckstrom, Rosa Beddington, Mark Bellis, Roger Bing-ham, Mark Boyce, John Browning, Stephen Budiansky, Edward Carr, Geoffrey Carr, Jeremy Cherfas, Alice Clarke, Nico Colchester, Charles Crawford, Francis Crick, Martin Daly, Kurt Darwin, Marian Dawkins, Richard Dawkins, Andrew Dobson, Emma Duncan, Peter Garson, Anthony Gottlieb, John Hartung, Peter Hudson, Anya Hurlbert, Mark Flinn, Archie Fraser, Steven Gaulin, Charles Godfray, Joel Heinen, Nigella Hillgarth, Michael Kinsley, Richard Ladle, Richard Machalek, Seth Masters, Patrick McKim, Graeme Mitchison, Oliver Morton, Randolph Nesse, Paul Neuburg, Paul Newton, Linda Partridge, Marion Petrie, Steve Pinker, Mike Polioudakis, Jeanne Regalski, Peter Richerson, Mark Ridley (being mistaken for whom has been a great benefit to me), Alan Rogers, Vincent Sarich, Terry Sejnowski, Miranda Seymour, Rachel Smolker, Beverly Strassmann, Jeremy Taylor, Nancy Thornhill, David Wilson, Edward Wilson, Adrian Wooldridge, and Bob Wright.

Several people helped even further by reading drafts of chapters and commenting on them: Their advice was time-consuming to them but immensely valuable to me: Laura Betzig, Mark Boyce, Helena Cronin, Richard Dawkins, Laurence Hurst, Geoffrey Miller, and Andrew Pomiankowski. I owe a special debt to Bill Hamilton, to whom I returned again and again for inspiration at the early stages of this project:

ACKNOWLEDGMENTS

::: IX :::

My agents, Felicity Bryan and Peter Ginsberg, were unfailingly encouraging and constructive at all stages: My editors at Penguin and Macmillan, Ravi Mirchandani, Judith Flanders, Bill Rosen, and especially Carrie Chase, were efficient, kind, and inspired.

My wife, Anya Hurlbert, read the entire book, and her advice and support throughout have been invaluable.

Lastly, thanks to the red squirrel that sometimes scratched at my window while I wrote: I still don ' t know which sex it was.

Chapter 1

HUMAN NATURE

The most curious part of the thing was, that the trees and the

other things round them never changed their places at all: howev-

er fast they went, they never seemed to pass anything: 'I wonder

if all the things move along with us?' thought poor puzzled

Alice: And the Queen seemed to guess her thoughts, for she cried,

'Faster! Don't try to talk!'

—Lewis Carroll, Through the Looking-Glass When a surgeon cuts into a body, he knows what he will find inside. If he is seeking the patient 's stomach, for example, he does not expect to find it in a different place in every patient. All people have stomachs, all human stomachs are roughly the same shape, and all are found in the same place. There are differences, no doubt.