A penny for your squats, push-ups

The study, published today in Nature, involved 61,293 American gym members, 30 prominent scientists working at 15 universities, and more than 50 different motivational programs. In addition to reward points, incentives ranged from a free audiobook for gym use to cheery instructions from researchers to reframe exercise as fun. While some of the programs galvanised additional gym visits, others, including some the scientists had absolutely expected to inspire more exercise, did not.

The study’s findings, positive and the reverse, offer timely insights into how the rest of us might better motivate ourselves to keep our upcoming New Year’s exercise resolutions. But just as important, the study, in its ambition, scope and structure, is meant to serve as a road map for future investigations into the mysteries of human behavior and why so many of us act as we do and sometimes, despite our best intentions, keep skipping that next spin class.

The science of human behavior, including whether and why we exercise, can be squishy and rife with research hurdles. Many past studies have looked at how to build habits, for instance, or instill confidence or stick to an exercise routine. But the vast majority of those studies have been small-scale or homogeneous, recruiting only affluent, well-educated white people, for example, or healthy, young college students, or only men or only women.

Those studies have also used a wide range of methods to track behavior change, making it difficult to compare data from one study to another. In addition, many have relied on subjective measures, such as asking people how they feel during and after a study, a topic on which we can be, intentionally or not, untrustworthy. The result has been a replication crisis in behavior science, with researchers unable to repeat the findings of many past studies, calling the original results into question.

These issues naturally concerned Katy Milkman, a professor at the Wharton School of the University of Pennsylvania and author of the 2021 book “How to Change” (one of Well’s favourite health books of the year) and her colleague Angela Duckworth, also a professor at Wharton and author of the 2016 best seller “Grit.” Among the foremost behavioural scientists at work today, they were convinced their field could and should become more scientifically rigorous, which led them to begin noodling with the notion of mega-studies.

A mega-study, as they defined the concept, would be large in scale, involving thousands of participants, and not the dozens commonly used in behavioural research. It would also randomly expose large groups of volunteers to a range of behavior modifications or other interventions, employing objective measures to assess whether an intervention had actually worked. These ideas brought the research team to the 24 Hour Fitness chain. Already, they had decided that one of their first mega-studies would concentrate on exercise behavior, in part because it is easy to measure increases or declines in workouts and visits to the gym, but also because encouraging people to exercise more can alter lives by boosting health.