Undercover Economist

How to keep your gym habit

‘Might a commitment strategy allow you to pay yourself to go to the gym?’

How are those resolutions going? Still going to the gym? If not, you’re not alone.

Let’s think about incentives. If some benevolent patron had paid you a modest sum — a few pounds a day, perhaps — for keeping your resolution throughout January, would that have helped you keep fit now that January is behind us?

The answer is far from clear. An optimistic view is that by paying you to look after yourself in January, your mysterious patron would have encouraged you to form good habits for the rest of the year. The most obvious case would be if you were trying to give up cigarettes; paying you to get through the worst of the withdrawal period might help a lot. Perhaps diet and exercise would be similarly habit-forming.

Yet some psychologists would argue that the payment is worse than useless, because payments can chip away at our intrinsic motivation to exercise. Once we start paying people to go to the gym or to lose weight, the theory goes, their inbuilt desire to do such things will be corroded. When the payments stop, things will be worse than if they had never started.

The idea that external rewards might crowd out intrinsic motivation is called overjustification. In a celebrated study in 1973 conducted by Mark Lepper, David Greene and Richard Nisbett, some pre-school children were promised sparkly certificates as a reward for drawing with special felt-tip pens. Others were given no such promise. When the special pens were reintroduced to the nursery classrooms a week or so later, without any reward on offer, the researchers found that the children who had previously been promised certificates for their earlier drawing now spent half as much time with the pens as their peers. Only suckers draw for free.

There’s a big difference between exercising and colouring, however: while many children like felt-tips, many adults do not like exercising. A payment can hardly crowd out your intrinsic motivation if you don’t have any intrinsic motivation in the first place. Systematic reviews of the overjustification effect suggest that incentives do no harm for activities that people find unappealing anyway.

So perhaps the idea of paying people to exercise is worth thinking about after all. In 2009, two behavioural economists, Gary Charness and Uri Gneezy, published the results of a pair of experiments in which they tried it. Some of their experimental subjects were paid $100 to go to the gym eight times in a month, while those in two alternative treatment groups were either paid $25 for going just once, or weren’t asked to go to the gym at all.

The results were a triumph for the habit-formation view. The payments worked even after they had stopped. In one study, the subjects were exercising twice as often seven weeks after the bonus payments stopped than before they started; in the other, the increase was threefold 13 weeks after payments had stopped. People who were already regular gym-goers didn’t change their behaviour — so there was no crowding-out — but there was a surge in exercise from people who hadn’t previously done much. A later study by Dan Acland and Matthew Levy found a similar habit-forming effect among students, although, alas, the good habits often failed to survive the winter vacation. In other experiments, incentive payments have been shown to be modestly successful at helping smokers to give up.

There is much to be said for a benign patron who pays you to stay healthy while you form good habits. But where might such a person be found? Take a look in the mirror — your patron might be you.

Inspired by the ideas of Nobel laureate Thomas Schelling, economists have become fascinated by the idea of commitment strategies, where your virtuous self takes steps to outmanoeuvre your weaker self before temptation strikes. A simple commitment strategy is to hand £500 to a trusted friend, with instructions that they are only to return the cash if you keep your resolution.

Might a commitment strategy allow you to pay yourself to go to the gym? It might indeed. Economists Heather Bower, Mark Stehr and Justin Sydnor recently published the results of a long-term experiment conducted with 1,000 employees of a Fortune 500 company. In this experiment, some employees were initially paid $10 for each visit to the company gym over a month. Some of them were then offered the opportunity to put money into a commitment savings account: if they kept exercising, the money would be returned; otherwise it would go to charity. The approach was no panacea: most people did not take up the option, and not everyone who did managed to stick to their goals. But even three years later, those who had been offered commitment accounts were 20 per cent more likely to be exercising than the control group.

That chimes with my experience. I once wrote a column about sending $1,000 to a company called Stickk, which promised to give it away if I didn’t exercise regularly. The contract was for a mere three months — and I succeeded. Eight years after my money was returned, I’m still sticking to the habit.

Written for and first published at ft.com.

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