It is one of the downsides of modern civilization. We no longer hunt or farm to survive, and our work is mostly sedentary, so we must choose to exercise to stay healthy. Going to the gym is an efficient way to work out, but finding the time and inclination to lift weights or run on a treadmill isn’t easy. I can think of a million things I’d rather do, and most of them involve food and Netflix. We would all like to go to the gym more, in theory, but in practice almost everything else seems more important or appealing in the moment. That’s why the majority of gym members pay dues every month and never go.
Economists have run several experiments over the years to understand the sign-up-but-never-go-to-the-gym problem—or, as they put it, resolve this dynamically inconsistent behavior. A new paper (pdf) went with a simple approach: pay people money to go to the gym. The researchers divided 836 new members of a gym into different groups. One group got a $30 Amazon gift card if they went nine times in six weeks. Another group got $60 a gift card if they went nine times. A control group got a $30 gift card whether or not they went. The average new member predicted that they would go to the gym three times a week.
It turns out that the incentive barely nudges people. In the first week of membership, the average person, in all groups, went to the gym twice a week. From then, gym trips dropped off rapidly. After eight weeks, the average person only went once a week. The groups that were paid to go had slightly better attendance, but any difference in their behavior wasn’t significant.
It could be that paying people—or paying them relatively modest amounts—isn’t enough encouragement to exercise. Indeed, behavioral economists believe taking something away from people is a more powerful incentive. They call this the endowment effect. It is based on the observation that people put a higher value on something they already own.
The researchers tried to capture the endowment effect by asking a fourth group of new gym members to pick out a $30 object on Amazon. The economists promised to give them the thing if they went to the gym nine times in six weeks, the same hurdle set for the others. The researchers even sent pictures of the $30 object to keep the gym members motivated during the experiment. But this didn’t work either—the group only went to the gym slightly more than the others, and not enough to derive a meaningful impact.
Perhaps more people would go if the researchers were able to make them pay $30, or give up something worth that amount that they already own, as punishment for skipping the gym. I pay an absurd amount to an luxury gym because seeing the money come out of my bank account makes me feel guilty. The guilt means I never miss a workout. That, and the eucalyptus-scented towels.