Because I'm Worth It: A Lab-Field Experiment on the Spillover Effects of Incentives in Health

We conduct a controlled lab-field experiment to directly test the short-run spillover effects of one-off financial incentives in health. We consider how incentives affect effort in a physical activity task - and then how they spillover to subsequent eating behaviour. Compared to a control group, we find that low incentives increase effort and have little effect on eating behaviour. High incentives also induce more effort but lead to significantly more excess calories consumed. The key behavioural driver appears to be the level of satisfaction associated with the physical activity task, which 'licensed' highly paid subjects to indulge in more energy-dense food.