Our past research has also shown that more information often isn’t enough to change behavior. A classic example is doctors who struggle to follow the same medical advice that they give to patients. Despite doctors’ extensive training and access to medical information, as a group, they are barely better than patients at sticking to recommendations for improving their health. This includes vaccinations. Rates of chickenpox vaccination among doctors’ children, for example, are not meaningfully different from the rates among children whose parents are not doctors. While most parents vaccinate their children against chickenpox, you would expect the rates among doctors’ families to be especially high.

What interventions might work? Behavioral science research suggests that one of the best ways to motivate behavior is through incentives, either positive or negative. Incentives work because they do not force people to change their beliefs. A customer might switch cellphone providers not because he believes the new provider is better, but because the new provider is offering a free iPhone to switch (a positive incentive). A teenager might come home before curfew on a Saturday night not because she believes it’s dangerous to be out late, but because she knows her parents will take away her car keys if she stays out past midnight (a negative incentive).