By guest blogger Juliet Hodges

Spreading information about the benefits of exercise – including how it reduces the risk of chronic diseases and improves mental health and wellbeing, from sleep quality to self-esteem – hasn’t been enough to change people’s behaviour. Only 30 to 40 per cent of adults in the UK say they get the recommended amount of physical activity per week, and this figure drops to just 5 per cent when using accelerometers to measure movement. It’s a similar story even for people who have made the effort to join a gym – in a recent poll, a third of members reported visiting their gym three times a year or less. It seems we need to get more creative to persuade people to get active.

To test out some innovative psychological approaches, a new study published in the Journal of Behavioral and Experimental Economics selected 181 infrequent gym-goers at the University of West Chester, who went on average less than once a week before the experiment. All students at the university have free access to the fitness centre, and their attendance is automatically recorded when they swipe in.

The researchers tested three types of intervention, in isolation or combined, over the course of three weeks. First was the financial incentive: everyone (except the control group) was entered into a lottery, with a chance to win an $80 Amazon voucher if they met their weekly exercise goal of three 30-minute sessions. Second, some participants were partnered up, and were only eligible for the lottery if both members of the team had met the goal. Finally, half of the participants were given information midweek about how many other individuals or teams had already reached the weekly target. In all, there were five participant groups: the control, individuals with information (about others’ attendance), individuals without information, teams with information and teams without information.

The lottery increased gym attendance in all groups during the study from their pre-experiment average of less than once a week. Individuals enrolled in the lottery on their own, but without information about others, more than doubled their attendance to almost 1.5 visits per week, although this effect was not statistically significant. The individuals enrolled in the lottery on their own and who also had access to information about other people’s behaviour increased their visits to almost twice per week. The most impressive result was for the participants enrolled in the lottery in a two-person team – whether they had access to information about other people’s behaviour or not, they tripled their average visit rate to more than three times per week.

The researchers also monitored behaviour for several weeks after the experiment. All groups kept going to the gym slightly more than they had done before the experiment, particularly the individuals with information. Looking specifically at non-users, defined as those who had not used the gym at all in the four weeks before the study, the researchers found that 80 per cent went at least once during and once after the intervention. Furthermore, non gym-users who received information were more likely to keep going than other groups. However, none of the interventions had a lasting effect beyond the Thanksgiving break four weeks after the experiment finished.

It is not entirely surprising that the lottery alone was less motivating than being in a team or receiving information. Financial incentives or penalties aren’t always the best way to change behaviour; as most of us know, paying for a gym membership is no guarantee you’ll actually go. However, other studies using financial rewards for exercise have found better uptake and maintenance even after they were removed. The less impressive results in the current study could be due to a number of reasons, such as the short duration of the experiment, the relatively small amount of money, or the reward being a lottery rather than a guaranteed amount.

Participants in teams exercised most frequently during the experiment, which is consistent with research in a range of domains that finds people are more motivated when others are also relying on them. The researchers didn’t indicate whether participants were introduced to their teammates, which can make these interventions more effective. People are less willing to disappoint people they know, so friends increase each other’s attendance when they are paired up, while an anonymous partner can be less effective than an individual incentive.

The mechanism behind the effectiveness of the information intervention is unclear. It could simply have acted as a reminder for people to squeeze three sessions in, prompting a spike in attendance towards the end of the week. The researchers suggest that knowing what others were doing could have made the lottery prize seem more accessible, as very few had completed three sessions by midweek. This seems more likely than a social norm explanation, which would assume the low numbers would reduce motivation.

It would be unwise to draw too many conclusions from this study, particularly given its short duration and limited sample size. It does however suggest that information and team dynamics, together or in isolation, can be cost-effective, easy-to-deliver ways to promote physical activity. For example, gyms could trial providing feedback on how many members had attended that week – although they may be unwilling to do so, given their business models often rely on people paying but not turning up.

—Get thee to the gym! A field experiment on improving exercise habits



Post written for the BPS Research Digest by Juliet Hodges. Juliet has a background in psychology and behavioural economics, and has applied this in advertising and now healthcare. Follow @hulietjodges on Twitter, LinkedIn or read her posts for the Bupa Newsroom here.