Kirgios, Mandel, Park, et al. (2020) on Temptation Bundling

Erika L. Kirgios, Graelin H. Mandel, Yeji Park, et al., “Teaching Temptation Bundling to Boost Exercise: A Field Experiment.” Organizational Behavior and Human Decision Processes 161: 20-35, 2020.

• Temptation bundling came to the world's attention (er, my attention) in a 2014 article by Milkman, Minson, and Volpp. Temptation bundling is when you pair a "should" behavior –exercise, for instance – with a "want" behavior, an indulgence such as listening to a captivating, somewhat trashy novel. The idea is that the pairing makes it more likely that you actually will engage in the "should" activity, and it will be more enjoyable than it would be without the tied "want," while you also will reduce the guilt feelings associated without giving in to an indulgence. Hmm, I might have some (vegan, of course) chocolate while blogging...

• The 2014 article had a pretty small sample size (226) and findings that suggested temptation bundling did provide, in the short-term, a boost to engagement with the "should" behavior.

• The 2020 article (which involves as a co-author Katherine Milkman, part of the original temptation bundling team) works with a commercial fitness company to test temptation bundling on a much larger sample. The experiment sticks with the audio books/exercise pairing, but with about 15 times the previous number of participants.

• A new question that is looked at is whether would-be exercisers actually have to be told about temptation bundling, or can an exercise gym company, by giving people an audiobook in the context of encouraging exercise, induce their customers to temptation bundle on their own? The term of art the authors employ is "information leakage." That is, even without being told or advised to bundle, maybe just being given access to an audio book by your gym induces temptation bundling.

• A chain of gyms introduced a 28-day long StepUp Program for their millions of members, with some rewards for participating. The Program was described as “a habit-building, science-based workout program [p. 23].” StepUp served as the locus for tons of research: "Our study was one of 20 preregistered studies embedded in the StepUp Program... [p. 23]." 

• Within the framework of the StepUp Program, more than 2,300 people participated in a temptation bundling experiment. About half of the participants were informed they had been gifted a free audiobook, and they received a code allowing them to choose and download a book. The other half received the same audiobook gift and were encouraged to use the book in a temptation bundle with exercise; this encouragement continued throughout the month.

• Most people (some 86%) didn’t bother to collect their free audiobook. Now I am sad. In some sense, we are back to a small sample: less than 200 subjects in each of the conditions downloaded their free audiobook. 

• Gym attendance is the main variable of interest. The free audiobook offer, whether paired with temptation bundling encouragement or not, increases workouts by something like 10 to 14%, both during the Program and up to 17 weeks later. (This result comes from a variation of the experiment that includes a third control group of participants who are not offered a free audiobook.)

• The marginal impact of the temptation bundling is pretty small (effectively zero during the 28-day treatment period), perhaps inducing some people to go to the gym (in the long run) who would not otherwise have gone. 

• A follow-up lab experiment establishes that information leakage might be what drives the very similar results for the audiobook treatments, with and without the temptation bundling encouragement. (As the lab experiment was not part of the original pre-registration, presumably its utility was understood only after the  original experiment showed near identical results for the two conditions.)

• In my view, this experiment removes a bit of the luster from temptation bundling. I'm a bit disappointed, really – not in the experiment itself, which is superb, but by the meh, alas, results.