Sex, murder, and the meaning of life : a psychologist investigates how evolution, cognition, and complexity are revolutionizing our view of human nature

This book is a light dash through evolutionary psychology. Other writers, such as Steven Pinker, get bogged down in details of the various systems of the mind, but not Kenrick. Kenrick ties each of his topics to stories from his own life and to simple, vivid analogies. Though there are notes and a bibliography at the end of the book, the text conveys only the briefest conclusion regarding a facet of the topic at hand after the personal story and a basic description of a psychological experiment. This text is an even lighter read than David Buss.

There are a number of sections that I found interesting and thought-provoking. I liked the revision of Maslow's hierarchy of needs. Though Maslow's hierarchy has been very appealing over the years, he had come up with his positive psychology without any real explanatory framework for why it should exist. Kenrick offers an evolutionary explanation for why a modified form of it should exist. Kenrick discusses the theory of the modularity of the mind by calling the modules "subselves." He gives each of the subselves a catchy moniker, which makes the theory more concrete and understandable.

Personally, I was struck with Kenrick's findings about the sexual politics of religion's communities. When I was a college student, I dated two different women who seemed to want to settle down, but were insistent that I join a conservative religious tradition if I wanted to get more serious. Years later, a friend of mine of liberal temperament was handed an ultimatum by a woman: he had to join a mysogynistic religious denomination in order to marry her. I said, "Think about it. You are about to join a religion that says that the wife must obey her husband, but you are doing it because she said you have to. Just think about that." Kenrick's findings confirm those observations.

In looking over Amazon reviews, I agree with the criticism that the book lacks depth. There are better, more thorough books on most of the topics he covers, but most of the potential readers who could breeze through this book would be stopped dead by those deeper books. I also agree that the tone can be condescending and self-centered. It doesn't surprise me from his personal stories that he is on his third wife. But as he explained, he has spent more time on tough street corners growing up than in polite tea rooms, so his voice is culturally a bit less refined and a bit more of a naked display of testosterone.

None of these criticisms take away from the fact that Kenrick has a knack for designing a psychological experiment that teases out mental distinctions and revealing possible evolutionary underpinnings of behavior. Kenrick demonstrates clearly the power of evolution as a paradigm that suggests experiments with interesting results, an example of what David Sloan Wilson meant by "evolution for everyone." Nevertheless, the descriptions of the experiments show how ambiguous psychological experiments can be. (In this way, his studies have a lot in common with those of David Buss.) One wonders how many tests have been done to make sure the results he reports are not artifacts of the lab setting. The brevity of the description leaves one with the impression that Kenrick and his colleagues slap together experiments and then quickly leap to broad conclusions. He hints that many of his results have been thoroughly confirmed elsewhere, and I would hope so.

Kenrick also glosses quickly over some major aspects of human nature. He makes a quick nod to David Sloan Wilson's theories about how religion may provide a social glue that allows a human society to behave like a superorganism with group-level selection. But if religion and war are methods of group selection that give altruistic individuals a selective advantage over selfish individuals, then that is a major aspect of human nature, which Kenrick mentions only in passing. Kenrick is the lead author of a textbook on social psychology, so I thought it was strange that he did not discuss the sort of group identity issues that Berreby discussed in "Us and Them" or that Waller discussed in "Becoming Evil."

Finally, there is the matter of "the meaning of life." Putting such a phrase into the title of a book signals an attitude that one is going to take one's topic and find very broad implications for the reader, indeed, the very broadest possible implications. The phrase is dangerous, because it sets up the highest of expectations in the mind of the reader. So it comes as no surprise that a number of Amazon reviews have criticized Kenrick for how the book handles "the meaning of life."

Traditional religious philosophers might use the phrase "the meaning of life" to denote the purpose and significance of the entire observable universe, which would, in most such metaphysical frameworks, be God. A thorough atheist might reject that definition, arguing that the universe as a whole doesn't have a purpose or a meaning, it just exists. Kenrick likewise does not have such an all-encompassing, metaphysical definition of the phrase in mind. Whether he rejects the theological question as meaningless or whether he just doesn't want to address it, I don't know; he doesn't say.

Kenrick does tackle two other definitions of the phrase "the meaning of life." The first can be summed up as: What can we say about the theoretical foundations of the behavioral sciences in relation to other sciences? The second can be summed up as: How can I live my life so that I derive deep satisfaction and personal meaning from it?

To the first question, Kenrick replies that the synergy of cognitive science (modular mind), evolutionary psychology, and complexity theory offer a new foundation for psychology and the behavioral sciences that integrates them with biology, chemistry and the rest of the natural sciences. Kenrick writes: "the revolution is over, and we are in the process of rebuilding a more unified and balanced republic of behavioral science" (201). To the second form of "meaning of life," Kenrick argues that our minds are shaped to make us feel most fulfilled when we are helping others as part of a loving community. He writes: "Human beings are ultimately designed not to seek ecstatic happiness from dawn to dusk but to be linked into a supportive web with other human beings" (203). 

All in all, the book is good at what it aims to be, which is a very basic popularization.