Environmentally friendly products are everywhere one looks. Energy efficient dishwashers, bamboo towels, the paperless Kindle and, of course, the ubiquitous Prius are all around. But why do people buy these "green" products? Do they care about the environment or is there something else at play?

"Green purchases are often motivated by status," says Vladas Griskevicius, assistant professor of marketing at the University of Minnesota's Carlson School of Management. "People want to be seen as being altruistic. Nothing communicates that better than by buying green products that often cost more and are of lower quality but benefit the environment for everyone."

In the recently published paper "Going Green to Be Seen: Status, Reputation, and Conspicuous Conservation," Griskevicius and co-authors find that people will forgo luxury and comfort for a green item. The catch? People will forgo indulging for themselves only when others can see it. "Many green purchases are rooted in the evolutionary idea of competitive altruism, the notion that people compete for status by trying to appear more altruistic," says Griskevicius. His research finds that when people shop alone online, they choose products that are luxurious and enhance comfort. But when in public, people's preferences for green products increases because most people want to be seen as caring altruists.

Nowhere is this clearer than the highly visible and easily identifiable Toyota Prius, which essentially functions as a mobile, self-promoting billboard for pro-environmentalism. "A reputation for being a caring individual gives you status and prestige. When you publicly display your environmentally friendly nature, you send the signal that you care," states Griskevicius.

Interestingly, the study also shows that status motives increased desirability of green products especially when such products cost more -- but not less -- relative to non-green products. This explains why the Prius price tag and why old-fashioned items like hand operated reel lawn mowers are holding their price. "When you are motivated by status, you will forgo luxury features to obtain an inferior green product that tells others that you care," Griskevicius says.

For entrepreneurs and companies looking to capture the green market, the key may be getting the product to be purchased and used in public. When others can see you do good, both you and the environment benefit. But in the privacy of ones home, luxury and comfort is still the winner.

Vladas Griskevicius's teaching and research utilizes theoretical principles from evolutionary biology to study consumers' often unconscious preferences, decision processes, and behavioral strategies. The paper, published in the Journal of Personality and Social Psychology, was co-authored by Joshua Tybur (University of New Mexico) and Bram Van den Bergh (Rotterdam School of Management).