One of the curious little mysteries of the coronavirus pandemic is why Japan's cases have increased so slowly. The country hasn't implemented the widespread testing of South Korea or the draconian lockdown of China. Yet the epidemic has spread only slowly there; the country has fewer than 1,000 cases as of this writing, lower than tiny Denmark with less than a 20th of the population. Some have suggested that Japan has a large number of undetected cases, but given the country's vulnerable elderly population the hospitals should be flooded with patients if this were true.
So what is Japan doing right? One possibility is that Japan's early move to close schools was a lucky success and that schools are the most important way the virus is spread. But another possibility is that Japan is simply very good at social distancing — avoiding groups of people and keeping physical distance from strangers. Despite living in densely urbanized areas, Japan is famous for social isolation. Relatively few young people live with roommates. The country's culture is geared around maintaining personal space whenever possible; greetings, for example, are done by bowing instead of shaking hands.
Also, many people wear surgical masks. Usually this is done by those with colds or flu, to prevent others from getting sick. A mask can block someone from exhaling infectious droplets. But perhaps more importantly, it can signal other people to keep their distance.
When most people use the word "signaling," they just mean any sort of communication. It's possible that wearing a mask could simply be an easy way of telling other people "I'm sick, stay away." A mask could also be used to send a false message, if people without symptoms simply want to ensure that others stay back.
But in economics, the word signaling has a special meaning. The basic idea is that people do something difficult or costly — for example, going through a fraternity initiation — to prove themselves in some way. Some believe that tattoos are a social signal; they're very visible and hard to remove, so they might represent a way that people prove that they're committed to a certain subculture. Economists have used the signaling idea to try to explain everything from college education to hipster mustaches (with varying degrees of plausibility).
Wearing a mask could serve as a relatively costly signal that someone is serious about social distancing. It's costly because it looks unattractive and causes other people to treat you with suspicion. Thus, it could be a forceful, effective message to others to stay away when otherwise they might not respect your boundaries.
The U.S. could benefit from this approach, especially now. In the U.S., where wearing masks isn't common or widely accepted, the signal could be even more powerful. Americans are unused to the idea of social distancing and many aren't yet taking it seriously. Furthermore, because many Americans don't understand how epidemics can explode in a very short period of time, they may be inclined to disobey shutdowns and party on as if nothing's wrong.
But if even a few more Americans wear masks, it could send a credible signal to all those who might otherwise disdain authoritarian government directives or breathless media reports. The mask-wearers would get funny looks or even taunts initially, but their presence would help convince their skeptical neighbors that this is an unusual and serious situation requiring an unusual and serious response.
The problem is that surgical masks now are in short supply. The U.S. isn't a big manufacturer of masks; it has chosen to outsource that task to China. So until production can be ramped up, most masks need to be reserved for medical use. A few Americans wearing masks as a social signal to encourage social distancing is fine, but if too many people do it, it can deprive hospitals of the materials they need.
Still, when mask production comes online, more Americans should consider adopting this common Japanese practice. Until then, Americans should consider using a face scarf instead. Coronavirus won't be the last pandemic, and teaching Americans how to shift into social distancing mode will bear lasting dividends.
This column does not necessarily reflect the opinion of Bloomberg LP and its owners. Noah Smith is a Bloomberg Opinion columnist. He was an assistant professor of finance at Stony Brook University, and he blogs at Noahpinion.