Bundle the boring with the tempting

There is a particular kind of standoff most of us know well. You know you should go for the run, and you would quite like to find out what happens next in the thriller you have been listening to. Left to their own devices, the thriller usually wins, and it wins on the sofa. The interesting question is what happens if you refuse to let those two things compete. What if the only time you are allowed the thriller is while you are running?

That small rearrangement has a name. It is called temptation bundling, and it is the subject of this fourth Rise Read. Fair warning before we start: the evidence here is thinner than in the earlier posts on the 66-day habit timeline, on if-then plans, and on tracking. It rests largely on two studies from one research group. I will be honest about that as we go.

What temptation bundling actually is

The idea, coined by the Wharton behavioural scientist Katherine Milkman and colleagues, is to take something you want to do but feel slightly guilty about, and something you should do but keep dodging, and glue them together with a single rule. You only get the want while you are doing the should. The audiobook only plays at the gym. The good coffee only happens while you clear the inbox. The trashy reality show only goes on while you fold the laundry.

The crucial detail, the one most casual descriptions drop, is the restriction. It is not a reward you collect afterwards. Milkman is firm on this point: enjoying a doughnut after a workout is not a bundle, it is just a treat. A bundle means the pleasure happens during the chore, so the chore stops feeling like pure cost. Take the restriction away and you are left with two activities that go back to competing.

The original study, and its actual numbers

The founding experiment was published in Management Science in 2014. It was small: 226 students, staff and faculty at a large American university, all of whom owned an iPod and already used the gym at least a little. They were split into three groups. One group got an iPod loaded with four page-turner audio novels they had picked from a list of 82, and that iPod lived in a locked locker at the gym. They could only reach it by turning up. A second group got the same novels on their own devices and were simply encouraged to save them for the gym. A third group got a gift card of equivalent value and no clever idea at all.

In the first week, the locked-locker group visited the gym about half as often again as the control group, while the encouraged-but-not-restricted group went just under a third more often. So the strong version, where access was genuinely locked to the gym, clearly beat the gentle version, where people were just told it was a good idea.

Then comes the part the motivational write-ups tend to skip. The effect faded. It shrank steadily week by week, and it fell away sharply after the Thanksgiving break, when the university gym shut and everyone's routine broke. When people came back from the holiday, the pull did not fully come back with them. So this is not a permanent rewiring. It is a nudge that leaks over time and is vulnerable to any interruption to the routine it is riding on.

There is one more twist, and it is a genuinely interesting one. At the end of the study, the researchers offered participants the chance to pay for the same locked-iPod arrangement for the coming term, something that, on paper, only reduces their freedom. Most still wanted it: 61 per cent named a price above zero, and the average person was willing to pay just under seven dollars to have their own future choices restricted. That tells you something about how well we know our own weaknesses.

The bigger follow-up, and what changed

Six years later, a larger study led by Erika Kirgios, with Milkman and others, tested a softer question at proper scale. Working with the gym chain 24 Hour Fitness and a programme that enrolled 6,792 people, they did not lock anything away. Instead they taught people the technique and gave them a free audiobook, then compared that with people who got no audiobook at all.

The headline is encouraging but modest. People who were taught to bundle and given something to bundle with were somewhat more likely to work out in a given week, and did around a tenth more workouts, and the benefit was still visible up to seventeen weeks after the programme ended. That durability is the best news in the whole literature. But when the researchers isolated the effect of the teaching alone, over and above simply handing someone a free audiobook, it was small, and it mostly showed up as getting people through the door at all rather than getting them to come more often.

Their explanation is neat. Giving someone a free audiobook inside an exercise programme quietly leaks the idea. People are sharp enough to work out what the audiobook is for without being lectured. Which means the enforced restriction in the first study probably did the heavy lifting, and merely suggesting the trick does less than you would hope.

Where the idea comes from

None of this is new. Underneath temptation bundling sits a much older principle from the psychologist David Premack, who showed in 1959 that a behaviour you do readily can be used to reinforce one you tend to avoid. Grandparents knew it too: eat your vegetables, then you get pudding.

The modern version is present bias, the well-documented human habit of overweighting whatever is in front of us right now and heavily discounting payoffs that come later. Exercise pays out later. The audiobook pays out now. Bundling smuggles an immediate reward into an activity whose benefits are otherwise annoyingly delayed, so for once your present bias pulls in the right direction. Milkman's framing leans on the economists Ted O'Donoghue and Matthew Rabin and their idea of "sophisticates", people who can see their own future lapses coming and set up structures to outwit them. The people paying to have their iPod locked away are exactly that kind of person.

The honest limits

Beyond those two studies and a handful of related ones, the cupboard is fairly bare. Work by Kaitlin Woolley and Ayelet Fishbach shows that focusing on the immediate enjoyment of a task, rather than its distant payoff, helps people persist, including a study where students given snacks, music and coloured pens stuck at hard maths problems for longer. That is supportive, but it is not the same thing as a locked bundle. And in a very large study across 61,293 members of the same gym chain, testing 54 different ways to boost attendance, fewer than half worked at all, and only a small fraction made any measurable difference once the programme was over. Bundling is a real effect, not a large one, and it sits in crowded, modest company.

There are also clear boundary conditions. Bundling only works when the want and the should can share your attention. An audiobook rides along nicely with a treadmill or the washing up. It fights with anything that needs deep focus. You cannot bundle a gripping podcast with writing a report, because both want the same part of your head. And if you have no real wish to do the should in the first place, no amount of bundling will rescue it.

Then there is self-enforcement, which is the whole game and the weakest link. The rule only has teeth if you keep the pleasure scarce. The moment you start enjoying the thriller on the sofa as well as on the run, the chore loses its only payoff and the bundle quietly collapses. The unenforced versions in both studies underperformed the strict ones for exactly this reason.

One more note, which connects to the last Rise Read. We wrote then about how measuring something can quietly turn a pleasure into work. It is worth watching for a cousin of that risk here. Pair your favourite show with a duty often enough and it may stop feeling like a treat. The evidence on this specific point is thin, so treat it as something to watch for rather than a proven cost.

Building a bundle that holds

If you want to try it, a few things follow from the research rather than from wishful thinking. Choose a want that is genuinely tempting but that you can take or leave, not something so irresistible you will cheat, and not something so lukewarm that losing it costs you nothing. Pair it with a should that is fairly mindless, so the two can coexist. Make the rule concrete, and as far as you can, make the temptation awkward to reach outside the bundle, because the locked locker mattered more than the good intention. Expect the pull to fade, especially after any break in routine, and plan to refresh the want when it goes stale. And be ready to referee yourself, because there is no one else in the room.

Bundling is not a transformation. It is a small, honest lever that makes a hard thing a little more inviting for a while. Used with clear eyes, that is often enough to get started, and getting started is usually the hard part.

If you track a habit in Rise Habits, a bundle is a natural thing to attach to it. The tracked square tells you whether the rule is holding. The bundle is one way to make the square easier to earn. Structure, as ever, tends to do quietly what willpower keeps promising and forgetting to do.

References

Etkin, J. (2016) 'The hidden cost of personal quantification', Journal of Consumer Research, 42(6), pp. 967-984. doi: 10.1093/jcr/ucv095.

Kirgios, E.L., Mandel, G.H., Park, Y., Milkman, K.L., Gromet, D.M., Kay, J.S. and Duckworth, A.L. (2020) 'Teaching temptation bundling to boost exercise: A field experiment', Organizational Behavior and Human Decision Processes, 161(Supplement), pp. 20-35. doi: 10.1016/j.obhdp.2020.09.003.

Milkman, K.L., Minson, J.A. and Volpp, K.G.M. (2014) 'Holding the Hunger Games hostage at the gym: An evaluation of temptation bundling', Management Science, 60(2), pp. 283-299. doi: 10.1287/mnsc.2013.1784.

Milkman, K.L., Gromet, D., Ho, H., Kay, J.S., Lee, T.W. et al. (2021) 'Megastudies improve the impact of applied behavioural science', Nature, 600(7889), pp. 478-483. doi: 10.1038/s41586-021-04128-4.

O'Donoghue, T. and Rabin, M. (1999) 'Doing it now or later', American Economic Review, 89(1), pp. 103-124. doi: 10.1257/aer.89.1.103.

Premack, D. (1959) 'Toward empirical behavior laws: I. Positive reinforcement', Psychological Review, 66(4), pp. 219-233. doi: 10.1037/h0040891.

Woolley, K. and Fishbach, A. (2016) 'For the fun of it: Harnessing immediate rewards to increase persistence in long-term goals', Journal of Consumer Research, 42(6), pp. 952-966. doi: 10.1093/jcr/ucv098.