Why Some People Go Green—and Others Don't

Why do some people love the Toyota Prius, but others couldn't care less about driving a hybrid vehicle? Why do some of your friends spend hours trying to reduce their carbon footprint, while others wonder what's the point of even recycling?

[See 15 Cars Fueling the Auto Recovery.]

In the Stanford Social Innovation Review last year, McKinsey consultants Sheila Bonini and Jeremy Oppenheim wrote that a third of U.S. consumers "are ready to buy green products or have already done so." Although market researchers have some idea of the size of the market, exactly what makes someone a "green consumer" is not as apparent. It may seem that all Prius drivers are Democrats and that Republicans are behind the wheels of Hummers, but a new book from Duke University social scientists Scott de Marchi and James T. Hamilton argues that political affiliation has very little to do with consumer decisions. In You Are What You Choose, de Marchi and Hamilton make the case that green consumerism—along with many other consumer habits—is largely determined by basic personality traits, not political beliefs.

Economists have long studied a few personality traits that play into consumer and financial decisions. How careful are consumers about risk? How much information does a consumer seek out before making a purchase? These traits tend to vary greatly from one person to the next. So de Marchi and Hamilton decided to look beyond what people bought and consider their personalities and habits. Each survey question counted as a mark toward or against a certain trait. Someone who said he or she always slows down for a yellow light, for example, would score more strongly as a person with a risk-averse trait. Someone who doesn't like to try new restaurants and instead sticks to old favorites would score high with the "stickiness" personality trait.

Armed with data on the personality traits of individuals, the authors then examined a range of everyday decisions—from what people buy to whom they vote for—and analyzed their choices to see how much of their decision-making differences were caused by differing personality traits. "We're better at predicting how you vote than if we asked about your policy opinions," de Marchi says. So—to use one prominent example from the book—what kind of a person is a green consumer?

1. Idea consumers. According to the authors, green consumers not only buy stuff, but they also buy ideas. Most consumers' daily purchases aren't motivated by ideology. Many people think only about the practicality of the things they buy, not the ideas they express by buying those things. For example, the act of buying a Prius often says something about the buyer—that he or she is concerned about gasoline consumption. For green consumers, that ideological benefit of the purchase often outweighs the practical benefit. "In a purely I-want-to-save-the environment sense, the extra money to buy a Prius makes no sense," says de Marchi. "You could buy a $10,000 or $15,000 cheaper car and use that money in a way to save the environment." In the book, he and Hamilton say a consumer could use that money to buy and preserve 120 acres of the Amazon rain forest.

For green consumers, certain intangible parts of a purchase are often more important than the product's practical use. Altruism is another trait de Marchi and Hamilton looked at. If someone donates blood or regularly gives to charities, he or she probably ranks high with the altruism trait, which green consumerism was found to be associated with. But you don't need to actually accomplish anything good to let altruism guide your consumer choices. The feeling of doing good—the "smile that recycling a can puts on your face," de Marchi suggests—is enough to make an altruistic person a green consumer.

2. Time minders. A key consideration in how consumers make most decisions—not just financial ones—is the degree to which they balance short-term costs and benefits versus long-term costs and benefits. For example, children are more likely to prefer one lollipop now to two lollipops a few days later. As they mature, many people become more willing to make sacrifices now for future returns. But not always: "Credit cards exist for a reason, even with the often spectacular rates they charge," says de Marchi.