Most of us know we should rein in our energy use. But to be successful, it'd help if we knew the best way to do it. So scientists asked more than 500 people, "What's the most effective thing you can do to conserve energy?" The results were illuminating. More than half the participants focused on conservation by curtailment: switching off the lights, changing thermostat settings and driving less. Only 12 percent went for efficiency: using compact fluorescent bulbs, insulating the house or driving a hybrid car. But scientists say that it's actually these moves that yield the bigger energy savings. The results appear in the Proceedings of the National Academy of Sciences. The study authors think that a big factor is that curtailment is easier to imagine doing—while efforts to improve efficiency would involve, for example, doing research about new appliances or cars, and spending money up front to buy them. But if people knew more about the actual energy requirements of their activities versus the savings available through efficiency, they might be spurred to act. To quote physicist and energy expert Arthur Rosenfeld: "Energy efficiency is like a Saudi Arabia under our cities."