Don’t smoke! Eat more vegetables! Get more exercise! Drink alcohol in moderation! Public health agencies bombard us with reason-based messages like these, in hopes of reducing the burden of cancer, atherosclerosis, diabetes, and other largely avoidable diseases. Yet the public health burden of these diseases remains vast, and some scientists question whether message-based public health campaigns are worth the effort. They point out that such campaigns principally engage the verbal, conscious, deliberative circuits of our brains—but automatic mental processes are what usually drive our unhealthy behaviors.
“Our current environments often cue unhealthy behaviors without our awareness,” says Theresa Marteau, a psychologist who directs the behavior and health eesearch unit at the University of Cambridge. Marteau and two colleagues authored a recent essay on the topic in Science, arguing that public health agencies should consider putting more emphasis on strategies that target our automatic brain processes. Such strategies—which might be termed “aim low” strategies—would involve altering the cues in our environments that normally direct us to unhealthy behaviors. Architects could design buildings in which stairs are easier to access than elevators, for example. Advertisers could be restricted in using imagery that subconsciously cues our brains to want cigarettes or junk food.
The observations on which such strategies are based are hardly cutting-edge. The authors cite a passage in an 1899 book by the psychologist William James: “Ninety-nine hundredths or, possibly, nine hundred and ninety-nine thousandths of our activity is purely automatic and habitual, from our rising in the morning to our lying down each night.”
Even so, governments have been slow to adopt the strategies being advocated, for political and ethical reasons as much as for scientific ones. “I do think this is—pardon the pun—a ‘no-brainer,’ in that we could do a better job this way of improving, say, people’s eating behavior and physical activity; but it’s not necessarily an easy approach for policymakers to take,” says Jonathan Moreno, a bioethicist at the University of Pennsylvania. “It’s a little awkward for them to say publicly that they’re going to appeal to our baser instincts.”
We humans take pride in our unusually strong ability to exert deliberate control over our own behaviors. In our brains, the “executive” regions of the late-evolved prefrontal cortex are wired extensively into other regions. This is thought to be a key feature that helps us to deliberate and behave according to long-term goals rather than impulsively and “unthinkingly.” Yet our deliberate control over our behaviors is far from complete. Our routine and instinctive behaviors are principally handled by automatic brain processes, which often seem to require reduced executive influence in order to work swiftly and efficiently. “The more of the details of our daily life we can hand over to the effortless custody of automatism,” James wrote, “the more our higher powers of mind will be set free for their own proper work.”
The problem for public health is that more or less automatic, environment-cued behaviors such as drinking a beer, wolfing down a fast-food burger, and lighting up a cigarette often continue to run on autopilot even when we try to stop them deliberately. Many habitual behaviors are also so strongly self-reinforcing, by their effects on pleasure and motivation circuits in the brain, that we consider them addictions. As Marteau and her colleagues note, public health campaigns that have used reason to try to persuade people have had “either modest or no effects on health-harming behaviors.” The estimated prevalence of type 2 diabetes continues to rise in the United States, for example, while that for cigarette smoking has declined hardly at all in the past decade.
The unfelt nudge
Marteau and others propose that a better strategy would be to alter, subtly but directly, the environmental stimuli that normally guide automatic behaviors, thereby subconsciously nudging these behaviors in desired directions. “Nudge” strategies for a variety of purposes already have been popularly advocated (and debated) by behavioral economists. However, many nudge strategies feature explicit interventions, such as the offering of monetary incentives to achieve some desired outcome. The strategies suggested by the “aim low” school would be less obvious to their intended beneficiaries.
In their paper, Marteau and her colleages cited a study that found that after the doors of several elevators were reprogrammed to close more slowly, people who approached the elevators were markedly more likely to take the stairs. In another study, making unhealthy food choices slightly less accessible in a cafeteria salad bar increased people's consumption of healthier, more accessible items.
A related strategy, which also has some experimental support, is simply to restrict advertisements for unhealthy products. Such advertisements normally feature images that subconsciously prime unhealthy behaviors, for example by depicting a juicy hamburger, a condensation-beaded bottle of beer, or happy, attractive people smoking cigarettes. Even images of popular brand logos can have priming effects. In one study, children reported that food with McDonald’s-branded packaging tasted better than identical but plain-packaged food. Organizations such as Yale University’s Rudd Center for Food Policy and Obesity, and the independent Center for Science in the Public Interest, have been prominent in urging restrictions on priming-laden advertising. Some aim-low proponents have urged the use of priming to motivate consumers against those products, e.g., by mandating images of cancer victims on cigarette packs.
Such strategies don’t merely target behavior more directly than reason-based strategies do. As Marteau and her colleagues note, they also can reach people who don’t respond well to traditional message-based campaigns—people who are less educated, less able to process complex health information, and less able to exert executive control over their behaviors.
Politics and ethics
Some governments already employ public health strategies that fit into the aim-low category. Canada and New Zealand, for example, require graphic and negative imagery on cigarette packs. But reason-based campaigns continue. “There has been a shift in thinking, but they’re still operating in both modes,” says Marteau. “And we still don’t know the effective ingredients [of aim-low techniques]—the precise mechanisms by which these environmental changes are affecting behavior.” She and her colleagues would like to see much more research, especially larger-scale research. “We don’t know about the effect sizes for a lot of these interventions; we have proofs of concept in laboratory studies, but very few data on effects in field studies,” she adds.
Martin Paulus, a neuroscientist and psychiatrist at the University of California at San Diego, notes as well that people exposed to such interventions would include some who have addictions and other behavioral disorders. “It is not clear that individuals with addiction, for example, have the same ability as normal people to change their behavior in response to these altered environmental cues,” he says.
There are also non-scientific obstacles to the widespread adoption of such strategies by public health agencies. “Policymakers may not want to emphasize the more automatic nature of our behavior,” Marteau says. “And those [i.e., makers of unhealthy products] who have a vested interest in the status quo can be expected to capitalize on that issue.” Indeed, U.S. tobacco companies have successfully sued to prevent the federal government from mandating aversive imagery—which more realistically depicts smoking’s consequences—on cigarette packs sold in the country.
Moreno notes that by a similar logic, the ability of the aim-low strategy to reach less-educated people may in fact be a political liability. “The idea that you use reason to appeal to wealthier and better-educated people, but you use baser means to appeal to poor people—you can understand why policymakers are reluctant to adopt that approach; they could be accused of gross paternalism,” he says.
The aim-low approach to public health campaigns could draw objections on ethical grounds too, especially where it involves the hidden manipulation of an ordinary environment. Private industry of course has been relatively free to practice techniques that influence us subconsciously, and even to devise these techniques for maximum impact on people of low socioeconomic status. However, governments and government-sponsored scientists, although they are trying to reduce the negative health effects of private-industry advertising, probably will be held to a higher ethical standard. “If you’re in government, it’s a little more sensitive, particularly if you know that people of lower socioeconomic status are more susceptible to this kind of manipulation,” Moreno says. As Paulus points out, scientists usually must obtain prior consent from subjects whom they intend to manipulate in such a manner. “People would rightly be alarmed if they suspect that public health messages are using ‘unconscious primes’ to change their behavior,” he says.
Marteau acknowledges that if product advertisers are behaving unethically, the government shouldn’t attempt to do the same. “One has to avoid the trap of two wrongs making a right,” she says. But some interventions, such as making healthier foods slightly more accessible than unhealthy ones, would seem too modest to draw ethical complaints. Others would involve merely the elimination or muting of existing cues that were put in place specifically to lead us to unhealthy behaviors—and Marteau emphasizes that our current environments are heavily biased by such cues. “Our current environments are not neutral,” she says.