Does sex education promote sex among children or discourage it? What about drug campaigns?

"Research on attitude formation has increasingly recognized that attitudes can be comprised of separate negative and positive components which can result in attitude ambivalence," explain Gavin Fitzsimons (Duke University), Joseph C. Nunes (University of Southern California), and Patti Williams (University of Pennsylvania). "In the present research we focus on vice behaviors, those for which consumers are likely to hold both positive and negative attitudes. We demonstrate that asking consumers to report their expectations regarding how often they will perform a vice behavior increases the incidence of these behaviors."

Intention questions are generally perceived as harmless, and the researchers found that this may cause consumers to lower the guard they would otherwise have with more explicitly persuasive pitches, such as advertising. In a series of three experiments, they demonstrate that seemingly benign questioning may serve as a liberating influence that allows consumers to give in to their desires more often than they would have otherwise.

For example, the researchers asked a group of actual college students how often they intended to skip class in the following week. Another control group of students was asked how often they intended to floss. Over the course of a semester, the group that was asked how often they intended to miss class ended up with one more absence, on average, than the group that was not asked.

As the authors explain: "Despite very real negative repercussions, respondents to a question about their future class attendance engaged in the negative behavior (missing class) at a significantly greater rate than those not asked to predict their behavior."

The results were especially pronounced for those with chronically low self-control, and the researchers point out that their findings pose a public policy dilemma for survey researchers who ask questions about vice behaviors in order to gain insight and discourage them.

"Fortunately, we also document two moderators of the effect that can prevent intention questions from exacerbating indulgences in vices," the researchers write, "(a) having people explicitly consider strategies for how they might avoid the behavior, and (b) having people create a self-reward for sticking with their stated usage patterns."

Gavan J. Fitzsimons, Joseph C. Nunes, and Patti Williams. "License to Sin: The Liberating Role of Reporting Expectations," Journal of Consumer Research: June 2007.