The logic of wearing masks to prevent coronavirus infection is confusing. Despite some equivocal early results, a recent study found that facemasks reduce transmission of the virus even when the masks are not completely effective in preventing droplets from passing through them, as long as the percentage of people wearing facemasks in public settings is in the 50-60% range. The trick to understanding these recommendations is that the type of cloth mask that most people are wearing has relatively limited benefits for the person wearing the mask. The benefit is really for other people in the room, and may be most helpful early in the course of infection when the mask-wearer is not yet showing any symptoms: Although people seem to be most contagious in the 1-3 days after symptoms begin, a substantial number of cases were spread by people who didn't yet know they had the virus. Mask-wearing is no substitute for having people who are sick stay at home, but presymptomatic transmission is a substantial risk in the current pandemic, and masks can help to prevent it.
The authors of the latest study suggest that the public health message about masks should be "my mask protects you; your mask protects me." This is exactly the opposite of how many people think about the purpose of masks. Early on, when the benefits of masks were still uncertain, people were wearing them simply to increase their sense of control over infection risk. Because non-medical-grade cloth masks provide only minimal protection for the wearer, CDC and WHO originally did not recommend their use. (That decision was also in part because the more effective medical masks were in short supply, and the agencies were worried that people would hoard them). But it has become increasingly clear that when a person who is contagious wears a mask, it does protect other people in the room. So, in other words, wearing a mask does only a little bit of good for me, but it may be extremely helpful to you.
Psychologist Daniel Kahneman and his colleagues have demonstrated that people are extremely bad at estimating risk under conditions of uncertainty. We treat probabilities that are very small (like the chance of contracting coronavirus in any given unmasked encounter) as though they could never happen. This leads us to discount small, cumulative risks that may add up over the course of the day. Furthermore, Kahneman and colleagues demonstrated that we are differentially sensitive to losses as compared to gains -- it's easier to motivate people by emphasizing what they personally stand to lose by not adopting a behavior. And we care more about what happens to ourselves and our immediate social circle than about strangers we might pass in a store. All of these cognitive tendencies are baked in to the Intuitive mind; they are simply ways that most people perceive the world, and they probably occur for valid evolutionary reasons. But they create a perfect storm when it comes to wearing masks, a behavior whose benefits are uncertain, that is designed to produce benefits for others rather than preventing risks to ourselves, and that mostly impacts strangers who we casually interact with in the course of daily life.
In economics, this type of problem is known under the label the tragedy of the commons. Economists have long known that when left to their own devices, people will make choices that have immediate benefits for them personally, even if a different choice might be better for society overall. The "commons" referred originally to a green space in the center of English towns where anyone could graze their animals. Another classic example is a lighthouse, which benefits everyone sailing ships in a dangerous area but which no individual person is incentivized to fund and maintain. The term now applies to any shared resource, like clean air and water, ocean fish stocks, fossil fuels, or the overall health of a large community. The coronavirus transmission rate in a community (R0) is a public good: The lower that number is, the better off every community member is on average. But the behavior required to produce the public good involves a small sacrifice of comfort or freedom by each member of the community. For our Intuitive minds, the tradeoff of minor discomfort to me personally versus uncertain benefit to strangers is a no-brainer: We will refuse the mask every time.
How, then, can we overcome our Intuitive tendencies in order to support public health? One way is by tying in to a superordinate Narrative like "my mask protects you, your mask protects me." That formulation emphasizes something our Intuitive minds do care about -- protecting ourselves -- while painting a total picture that includes the target behavior of me wearing a mask. Another good one that I heard recently is "wearing a mask is patriotic, because patriots sacrifice for the common good." This is appealing because it ties into moral foundations of tradition and group affiliation, perhaps particularly in light of the upcoming July Fourth holiday.
We know, however, that Narratives have only weak influences on behavior compared to Intuitive experiences like discomfort and inconvenience. A different approach is to create losses associated with not wearing a mask, in particular loss of face or social standing. If most people in a group wear masks, others will tend to wear them as well. In a behavioral economics study that tried to get people to re-use hotel towels, Narrative messages like saving the environment were much less effective than a simple social-pressure message saying "most people who stay in this hotel reuse their towels; won't you hang yours up for re-use, too?" The more people who wear masks, therefore, the more other people are likely to join them. Even a minority position can affect a large group, as long as those who engage in the unpopular behavior do it consistently, appear reasonable, and project confidence in their position. Similarly, one of the best things that leaders can do to promote mask-wearing is simply to wear masks themselves; this type of modeling can do more than any policy or use of consequences. Finally, of course, one can impose external consequences for failure to wear masks, like legal sanctions or fines. Given Americans' emphasis on personal liberty as a moral foundation, however, such a strategy may be less likely to succeed in the U.S.
For a psychologist, mask-wearing is a great example of behavioral principles that are well-known. There are inherent psychological barriers to mask-wearing, and education or exhortation are not likely to change anyone's opinion on the matter. Authoritarian enforcement of mask-wearing is likely to be hard, and is currently left to lower-level employees who may be vulnerable to retaliation and unwilling to force the issue. We will all be better off if we can use behavioral science to harness Narratives as well as Intuitive-level social pressures to gently encourage everyone to wear a mask.
Credit this week to Samantha Meiring for the patriotism narrative example, and to Dr. Kevin Masters for a conversation that made me consider the psychology of mask-wearing.
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