Why Sex Matters: A Darwinian Look at Human Behavior [Paperback]

With a thesis that could be subtitled: "Sex, Power and Resources," the book is principally about the ecology of sex differences - the conditions under which we predict male and female behavior to be more, and less, alike. Low points out (chapters 1-3) that [1] we seldom actually know the genetics of any trait, and [2] mostly what we do is ask: what strategies succeed reproductively in particular environments?

In chapters 4-15 she offers a tour de force of the selective pressures that have created the complex behavior of such a species as ours. The exploration of the evolutionary basis for our systems of mate selection, politics, war, cooperation, and resource accumulation make Why Sex Matters such an important book.

This book is highly readable, with dozens of tales, quotes and legends that help tie it to the heart of the human condition, but its strength is in leaving myth behind and explaining behavior through the science of ecology.

I found the book fascinating and will gladly place it on the same shelf as E.O.Wilson's, On Human Nature, Richard Dawkin's, The Blind Watchmaker, and Jared Diamond's, Guns, Germs & Steel.

Thane Maynard, Director of Education, Cincinnati Zoo & Botanical Garden

Low, who is a professor of ecology at the University of Michigan, assumes the point of view of an evolutionary biologist as she asks the question, how are men and women different and why? She is particularly focused on how the sexes differentially use resources to further reproduction, and asks which behaviors are ephemeral, due to present conditions, and which are more enduring, having proven adaptive over longer periods of time and in differing environments. She faces squarely the unsettling feeling that some people get when they contemplate humans purely as biological entities--or "critters," to use her expression. As she tells us in the preface, there are three themes guiding her work: One, "resources are useful in...survival and reproduction"; two, "the sexes...differ in how they...use resources"; and three, "each sex accomplishes these ends" by reacting to the environment differently. The result of this structured approach is a clear introductory course in sexuality from an evolutionary point of view, and a fascinating read.

Because Low employs resources from a wide variety of disciplines, including sociobiology, evolutionary psychology, behavioral genetics, ecology, anthropology, sociology, biology, history, etc., not to mention pop culture and world literature, her work is highly persuasive in a scientific sense. And because she studiously avoids squabbling among the disciplines, her work is psychologically compelling. There is material on cultural transmissions as well as natural selection. Demographers are given currency along with evolutionary biologists. One gets the sense that she has read just about everything and has thoroughly evaluated what she has read. Particular interesting to me is her discussion of the tangled origins of sexuality and the (non-obvious) nature of altruism. The chapters on warfare, "Sex, Resources, and Early Warfare," and "The Ecology of Warfare" are worth the price of the book alone. There we see that women warriors are rare because men can gain reproductive advantage through warfare but women cannot (p. 216). Low suggests that war may be an example of "runaway sexual selection" and its practitioners may have become "unhooked" from the old reproductive rewards, but that the proximate rewards remain. Low soberly faces the prospect of future warfare when small groups of people may acquire monstrous weapons, noting that "given a short-term gain...versus an unspecifiable risk of nuclear warfare...in the future, we do not predict restraint."

It should be clear that Low is a professional academician and not a journalist, as some popular writers on evolution are (Matt Ridley and Robert Wright, to name two of the best), and as such careful about her assertions. She doesn't espouse pet theories that may be overturned tomorrow; but she isn't afraid to voice her opinion. To give you a sense of her careful style, note the stunning qualification in the parenthetical in this statement from page 217 (and the sly irony): "Human war can become more complex and varied than intergroup aggression in other species, largely as a result of the development of technology (which itself is probably a product of intelligence)." Probably, indeed!

In the chapter on "Politics and Reproduction" we learn that men seek political power for reproductive gain (p. 211) but in the modern nation state may have to settle for proximate gains (which may be an irony not lost on Bill Clinton). Women, however, can gain little or no reproductive advantage directly for themselves, which may be the reason there are relatively few women in the top positions of political power in most human societies.

Some of this I admit is tough going. The material on "The Group Selection Muddle" in Chapter Nine is still muddled in my mind, and I couldn't figure out the point of the Summary of Selection Theories (Table 9.1 on pages 156-157). But evolution and the disciplines that address human behavior are complex, in some ways, deceptively so.

Professor Low is wise, temperate, thorough and more objective than seems possible in such a vibrant and contentious academic field. I suspect that this book started out as an undergraduate text, but somewhere along the line those reading the manuscript realized that it was so interesting and valuable that it could be published as a trade book aimed at a general readership. If you have time to read only one book on human nature, read this one. You will learn more than you would from half a dozen "popular" expositions, and you will have a sense of having learned something important and valuable. I wish I knew what is in this book when I was one and twenty. I would have conducted my life with a lot more grace and effectiveness.