[Editor's Note: This article has been updated to change the headline from "game theory" to "gamification." We apologize for "hijacking" the wrong term.]

From the "Prius effect," when hybrid drivers use feedback on their car dashboards to challenge themselves to drive more efficiently, to utility consumers in Sacramento competing with their neighbors to see who can save the most energy, games are increasingly used as a tool to help increase sustainable behavior.

At the recent Sustainable Brands conference, a gaming expert named Gabe Zichermann shared strategies for companies to harness the power of games. He pointed out that it's the pleasure of play itself, not the subject of a game, that makes people participate.

On Facebook, Farmville requires plowing fields, planting crops, and other manual labor. "Does that sound like fun?" Zichermann asked the crowd. "That's work our forefathers gave up in the Middle Ages." And yet over 40 million players play Farmville.

That appetite for games can be a powerful tool for driving sustainability, and more and more organizations recognize this. They also recognize games as a major source of competition for online audiences. Kiva president Premal Shah has referred to Zynga, the producer of Farmville, as Kiva's largest competitor. I recently spoke with Gabe to learn more about gamification.

Adele Peters: What is gamification?

Gabe Zichermann: It's the process of using game thinking and game mechanics to engage audiences and solve problems. It's a process, not a destination; we don't just magically arrive at a point where something is "gamified." Game thinking is really just a product of being exposed to games -- how we think about the world differently when we've been exposed to an idea over time.

Shakespeare said "all the world's a stage," but if he were alive today, a better metaphor might be "all the world's a game." Game mechanics are the tools that game developers use to make games -- things like points, badges, levels, leader boards, challenges -- those are all mechanics.

Gamification is really about taking the lessons of games at a high level, and the techniques of games, and putting them in a non-game context. Usually that's meant to solve a problem of some kind. On the marketing side, that's usually engagement-related, and on the do-gooder side, we think about fixing the world; getting people to be a better version of themselves.

AP: You've mentioned dashboards in hybrid cars, that give feedback on how efficiently drivers are performing, as a good example of a game improving sustainable behavior.

GZ: The cars are interesting. This is an important lesson for sustainability advocacy -- the car dashboard is not strictly speaking an effort to reduce environmental impact. It wasn't designed for that, actually.

Car manufacturers put it in to provide feedback about why the vehicle's core meaning -- why its actual value -- was real. You buy this car because you want to save money and save the environment, but if it didn't have that dashboard feedback, you wouldn't know how well you were doing.

Next page: Two examples of change-oriented green games