Drawing Lines and the Publicity Principle

Drawing Lines and the Publicity Principle

A number of years ago Sunstein took his daughter to Lollapalooza, the three-day rock festival held in midsummer in Chicago. On Friday night, a huge sign with changing electronic messages often showed the schedule of performances, but interspersed that information with a message saying, “Drink more water.” The print was large; the message was accompanied by another one: “You sweat in the heat: You lose water.”

What was the point of this announcement? Chicago had been in the midst of a terrible heat wave, and those who ran Lollapalooza were clearly trying to prevent the various health problems that are associated with dehydration. The sign was a nudge. No one was forced to drink. But those who created the content for the sign were sensitive to how people think. In particular, the choice of the particular words more water was excellent. Those words might be more effective than blander alternatives, such as “Drink enough water” or “Drink water.” The suggestion that we “lose water” could appeal to loss aversion on behalf of staying hydrated. (As it happens, Sunstein wished that he had seen the sign earlier; he became very thirsty during the performance, but the crowd was so densely packed that it was impossible to go out to find water.)

Now compare an imaginable alternative. Suppose that instead of having a visible “Drink more water” sign, the schedules for the day were briefly and invisibly interrupted by subliminal messaging, that is, stimuli that are not consciously noticed but nevertheless register enough to alter beliefs or behavior. The subliminal message might say, “Drink more water,” “Aren’t you thirsty???” “Don’t drink and drive,” “Drugs kill,” “Support your president,” “Abortion is murder,” “Buy ten copies of Nudge.” Can subliminal messages, including paid advertising, be seen as a form of libertarian paternalism? After all, they steer people’s choices, but they do not make their decisions for them.

We do not embrace subliminal messaging, and we do not count it as libertarian paternalism, even if it is used in the service of desirable ends. A general objection to libertarian paternalism, and to certain kinds of nudges, might be that they are insidious—that they empower government to maneuver people in its preferred directions, and at the same time provide officials with excellent tools by which to accomplish that task. Compare subliminal advertising to something just as cunning: If you want people to lose weight, one effective strategy is to put mirrors in the cafeteria. When people see themselves in the mirror, they might eat less if they are chubby. Is this okay? And if mirrors are acceptable, what about those that are intentionally unflattering? (We seem to run into more of those every year.) Are such mirrors an acceptable strategy for a cafeteria manager? If so, what should we think about flattering mirrors in a fast food restaurant?

These questions bring us to a guiding principle: transparency. In this context we endorse what the philosopher John Rawls called the publicity principle. In its simplest form, the publicity principle suggests that no choice architect in the public or private sector should adopt a policy that she would not be able or willing to defend publicly. We like this principle on two grounds. The first is practical. If a firm or government adopts a policy that it could not easily defend publicly, it stands to face considerable embarrassment, and perhaps much worse, if the policy and its grounds are disclosed. We urge our colleagues and students to adopt this policy for all important choices in their personal and professional lives. The second, more important ground involves the idea of respect. Organizations of all forms should respect people, and if they adopt policies that they could not and would not defend in public, they fail to show that respect. Instead, they treat citizens as tools for their own use or manipulation.

We think that the publicity principle is a good guideline for constraining and implementing nudges, in both the public and private sectors. In the U.S. government, regulations are generally proposed to the public for comment and review before they are finalized; this includes many in the category of nudges. Some examples include fuel economy labels, nutrition facts panels, and graphic warnings for cigarettes. The nudges are transparent, and so are the supporting reasons.

The same conclusion holds for legal default rules. If government alters such rules—to encourage organ donation or environmental protection, or to reduce age discrimination—it should not be secretive about what it is doing. It should disclose its action, and it should explain it (and preferably allow members of the public to comment in advance). The same can be said for educational campaigns that enlist behavioral findings in order to provide a helpful nudge. If government officials use cleverly worded signs to reduce litter, deter theft, or encourage people to register as organ donors, they should be happy to reveal both their methods and their motives. Consider an American advertisement from long ago showing an egg frying in a hot skillet with the voice-over, “This is your brain on drugs.” The vivid image was designed to trigger fear of drug use. Whether or not the advertisement is deemed manipulative, it did not violate the publicity principle.

So, to be clear, we like the idea of a bill of rights for nudging, and it should forbid subliminal advertising.