Today on ST, we speak by phone with Douglas T. Kenrick, a professor of psychology at Arizona State University. He's also one of the co-authors of a recent book, "The Rational Animal: How Evolution Made Us Smarter Than We Think," which a reviewer for Mother Jones magazine calls "a fun romp through the comedy of human errors. Again and again, the authors find, evolutionary urges and hardwired brains explain behaviors rational economists cannot. Humans just don't make sense, it seems, unless you expect them not to." And as was noted, further, of this volume in Booklist: "Sheer stupidity is what economic rationalists see when Elvis Presley buys 100 glitzy Cadillacs, when New York governor Eliot Spitzer pays as much as $80,000 for escort services, and when Steven Spielberg invests with Bernie Madoff. But [co-authors] Kenrick and Griskevicius see something more complex. In these apparently stupid decisions, they discern the results of an evolutionary history that impels men and women to ignore their own immediate self-interest in ways that ultimately foster the biological success of the species. That biological success, the authors argue, depends on a human identity that evolution has partitioned into seven separate subselves, each serving a different fundamental human need: self-protection, disease avoidance, affiliation, status, mate acquisition, mate retention, and kin care. When the environment triggers behaviors inscribed in any of these subselves, economic rationality may go out the window. Some readers may protest that the authors are offering biological justifications for foolishness. But the authors actually provide readers with helpful strategies for managing their evolutionary subselves prudently. A persuasive --- and entertaining --- look at the Darwinian dynamics of decision-making."