There’s a lot of research on why people do things. There are theories that say that behavior is largely rational — that people will copy behaviors if rewarded, and that we can predict behaviors based on attitudes. When trying to change behavior, research says that exploring these rationales by talking with the audience upfront is key.

The growing field of behavioral economics says the opposite — that behavior can be irrational. We often don’t think before we act, and external factors can be quite influential. Forbes profiled a company called StickK that gets people to pledge to achieve a goal — say, $100 toward losing 20 pounds. If they succeed, they get the hundred back. If they fail, they forfeit it to a charity or a friend. The principle is that the threat of losing the money — the stick — is more motivating than the pleasure of getting it back, and these incentives (the carrot and the stick, get it?) are far more effective than simply promising yourself that you’re going to lose weight. Logic may help set intention, but external influences seal the deal. It’s not necessarily rational, but it’s behavioral.

The White House is betting on our susceptibility to external prompts as well. Its Social and Behavioral Sciences Team, profiled in the September 24 issue of Time, is using behavioral economics to get people to do things like make double-sided copies and apply for financial aid. How do you encourage people to file their taxes on time? Simple! Send them an email saying that the majority of their neighbors have already done so. According to OPower, peer pressure works in getting people to use less energy at home, too.

We believe that there’s room for all of this in the field of behavior change. Nudging someone to check their blood pressure regularly can help fight heart disease. So can answering an audience call for more information about the disease’s warning signs.

It all comes down to understanding why your audience makes the choices they do — the good ones, and the not-so-good ones as well.