THOSE WHO DEVOTE THEIR LIVESto penetrating the mysteries of human nature face an unusual circumstance, one in which the targets of study happen to include their own minds. Sometimes it’s a personal insight that leads to a scientific discovery, but in my case, it was a scientific finding that led to a personal revelation. In one of my first formal studies of jealousy, we asked women and men to imagine their partner having sex with someone else. Some people displayed intense sexual jealousy, shaking with rage when these disturbing images filled their heads. Others seemed less upset, at least on the surface. I wanted to find out why. One critical factor turned out to be whether or not a person had already experienced a committed sexual relationship. Those who were either in love or who had loved and lost, displayed far more florid sexual jealousy than those who merely longed for love but had never experienced it.
As these results rolled off the computer printer, memories flooded my head of previously buried events of my past. As a youth of 17, influenced no doubt by the prevailing cultural ideologies of the time, I publicly proclaimed that my girlfriend’s body was her own, that she could have sex with anyone she wanted, and that jealousy was an immature emotion of up-tight, hung-up, unliberated individuals. I, of course, was above all that. There was only one problem—I didn’t have a girlfriend! A year later, when I became involved for the first time, my feelings about the matter suddenly reversed. It was as though a jealousy switch in my brain, previously on the “off ” setting, suddenly got flipped to “on.” I found myself glaring at other men who seemed a bit too friendly to my partner at parties, calling her up unexpectedly just to see whether she was where she said she would be, and thinking that every man harbored secret desires for her. I became aware of a deep dimension of my own psychology that had previously lain dormant.
Over the past decade, together with many talented colleagues, my scientific research has focused on the dangerous passion of jealousy and its tethered soul mate, the specter of infidelity. In the course of this work I discovered that some private demons are surprisingly widespread afflictions. This book represents a synthesis of that work, as well as of studies conducted by hundreds of scientists from around the world. I owe a deep debt to many who contributed directly or indirectly to its content and form. The first thanks goes to Don Symons, who helped me through friendship, published writings, dozens of discussions, and generous feedback on my work. Next, I owe special gratitude to Leda Cosmides and John Tooby, whose seminal writings and hours of lively discussion now spanning nearly two decades have greatly influenced my thinking. Martin Daly and Margo Wilson pioneered the exploration of the perilous passion, illuminated its special danger to women, and have generously helped to clarify my thinking over the years.
My direct-research collaborators deserve special thanks. I’ve had the good fortune to work with Alois Angleitner, Armen Asherian, Mike Barnes, Kevin Bennett, April Bleske, Mike Botwin, Bram Buunk, Jae Choe, Ken Craik, Lisa Dedden, Todd DeKay, Josh Duntley, Bruce Ellis, Barry Friedman, Steve Gangestad, Arlette Greer, Heidi Greiling, Mariko Hasegawa, Toshikazu Hasegawa, Martie Haselton, Doug Kenrick, Lee Kirkpatrick, Randy Larsen, Neil Malamuth, Victor Oubaid, David Schmitt, Jennifer Semmelroth, Todd Shackelford, and Drew Westen.
The incomparable Todd Shackelford must be singled out, since one could not ask for a more superlative collaborator. He has been co-author with me on more than a dozen publications on topics ranging from signals of infidelity to tactics men and women use to keep mates. Heidi Greiling helped to get me out of my male mind enough to collaborate on a raft of studies on the hidden dimensions of women’s sexual psychology. Martie Haselton, primary author ofError Management Theory, brought insight to the signal detection problem and the importance of women’s ovulation cycles. Josh Duntley contributed to understanding the extreme violence that jealous men sometime direct against women. April Bleske helped me to understand why friends are sometimes rivals and why men and women have so much difficulty being “just friends.” Barry Friedman helped to explore how men and women “test” mating bonds.
Discussions with many other colleagues also influenced the ideas expressed in this book: Dick Alexander, Rosalind Arden, Robin Baker, Jerry Barkow, Laura Betzig, Nap Chagnon, Helena Cronin, Richard Dawkins, Irv DeVore, Randy Diehl, Paul Ekman, Steve Gangestad, Bill Hamilton, Kim Hill, Sarah Hrdy, Bill Jankowiak, Doug Jones, Doug Kenrick, Lee Kirkpatrick, Kevin MacDonald, Neil Malamuth, Geoffrey Miller, Randy Nesse, Dick Nisbett, Laura Nitzberg, Steve Pinker, David Rowe, Jeff Simpson, Dev Singh, Barb Smuts, Frank Sulloway, Del Thiessen, Nancy Thornhill, Randy Thornhill, Bill Tooke, John Townsend, Robert Trivers, Jerry Wakefield, Lee Willerman, George Williams, D.S. Wilson, E.O. Wilson, and Richard Wrangham.
My agents, Katinka Matson and John Brockman, were instrumental in helping me to shape the vision for this book. Philip Rappaport, of The Free Press, trained his fine editorial eye on an early draft of this book and brought a unique sensibility to its final tone. Rosemary Davidson, of Bloomsbury Publishers, April Bleske, Joshua Duntley, Barry Friedman, Martie Haselton, and Todd Shackelford all offered insightful comments on the entire book.
Finally, I owe special thanks to the thousands of women and men who generously opened their lives to reveal some of the darker secrets of the dangerous passion.