Book excerpt: Why do three out of four professional football players go bankrupt? How can illiterate jungle dwellers pass a test that tricks Harvard philosophers? And why do billionaires work so hard -- only to give their hard-earned money away? When it comes to making decisions, the classic view is that humans are eminently rational. But growing evidence suggests instead that our choices are often irrational, biased, and occasionally even moronic. Which view is right -- or is there another possibility? In this animated tour of the inner workings of the mind, psychologist Douglas T. Kenrick and business professor Vladas Griskevicius challenge the prevailing views of decision making, and present a new alternative grounded in evolutionary science. By connecting our modern behaviors to their ancestral roots, they reveal that underneath our seemingly foolish tendencies is an exceptionally wise system of decision making. From investing money to choosing a job, from buying a car to choosing a romantic partner, our choices are driven by deep-seated evolutionary goals. Because each of us has multiple evolutionary goals, though, new research reveals something radical -- there's more than one "you" making decisions. Although it feels as if there is just one single "self" inside your head, your mind actually contains several different subselves, each one steering you in a different direction when it takes its turn at the controls. The Rational Animal will transform the way you think about decision making. And along the way, you'll discover the intimate connections between ovulating strippers, Wall Street financiers, testosterone-crazed skateboarders, Steve Jobs, Elvis Presley, and you.