Don’t assume masks and other public health interventions encourage risky behavior

This article originally appeared in the Behavioral Scientist, a magazine that examines the world through the science of human behavior.

My job is to experiment on people. That means I’m constantly trying to predict how people will react. If I make people think about their own mortality, will they respond with fear and caution or a devil-may-care attitude? If people feel socially rejected, will they feel desperate for friends or want to go it alone? If I ask men to read about women cheating on their partners, will that make them cling to their girlfriends or more likely to want to cheat?

Over the years, what I’ve learned is that people are hard to predict based on logic alone. I can almost always form a logical prediction in one direction and then another completely logical prediction in the opposite direction. Without actual data, I’m wary of making assumptions in one direction.

Thus, I was astounded to hear public health experts so certain that masks would make people reckless. In the critical early days of the pandemic, when societies were scrambling to decide how to respond, the World Health Organization put out guidance on masks. They warned that masks “create a false sense of security that can lead to neglecting other essential measures such as hand hygiene practices.”

The idea is that people think masks are a cure-all, so they put themselves in dangerous situations and ignore other measures like washing their hands. It’s similar to the idea that seat belts actually cause harm because people feel protected and therefore drive more recklessly. But careful analysis finds seat belts do actually reduce deaths.

Attitudes on masks have changed a lot since that mask-discouraging document. Yet even after changing its recommendation on masks, the WHO director-general was still warning in June that masks make people reckless.

The WHO is not alone. The European CDC, infectious disease experts and a Harvard professor have all warned that masks will create recklessness.

It’s also not unique to the coronavirus. The idea that helping people protect themselves actually makes them worse off emerges often. Sometimes this belief turns into a warning. Sometimes it causes authorities to conclude that the risk entirely outweighs the benefit, which means we shouldn’t even have the protection.

When wildfires were choking California in 2018, the Sacramento Fire Department started handing out free N95 masks. Soon the National Environmental Health Association said the masks would give people a false sense of security, and the program was shut down. Without data, health experts decided no protection was better than some protection.

Here’s the crux. This hypothesis seems plausible, yet so does the alternative — that masks make people more careful. So why is the message from public health experts so consistently in one direction?

I know well that, without data, both predictions seem plausible. But we have data. A clever new working paper (not yet peer-reviewed) from a team of economists in Germany tested this idea during the COVID-19 pandemic. They randomly assigned research assistants in Berlin to wait in outdoor lines with or without masks. Then they secretly measured how far away other people stood from them in line.

Did the masks give people a false sense of security and encourage people to stand closer together? Just the opposite. When the assistant waiting in line was wearing a mask, people stood slightly farther away. It wasn’t much — about 9 centimeters farther away on average. But it was certainly no invitation for recklessness.

That’s how people reacted to another person wearing a mask. But results were similar for people who showed up to the line wearing a mask. People who showed up wearing masks also stood farther away.

In defense of the WHO, maybe this data is too new. Maybe they haven’t heard about it yet. Researchers have run six separate studies, as far back as 2008, randomly assigning people to wear masks and then tracking whether they stop washing their hands. Four studies found no change; two found people responded by washing their hands more.

This fear of interventions isn’t unique to masks. When researchers developed a vaccine against the sexually transmitted virus HPV, some parents and public health experts warned that it could encourage people to have more risky sex. But studies have found the vaccine was associated with less unprotected sex and fewer infections.

By this point, these findings shouldn’t be so counterintuitive. Health interventions like masks and vaccines seem to communicate to people that there’s a serious problem. I started wearing pollution masks in Beijing in 2008. It was tough because even though the air pollution made me cough, the mask made me stick out like a sore thumb. People stared. But people also seemed to interpret it as a message. Several times strangers on the street asked me if the air really was that dangerous.

In the future, we will face more new dangers and more uncertain interventions. When that happens, the accumulated data tells me we should start with the assumption that interventions are at least as likely to make people more cautious.

With COVID-19, we lost time — and probably lives — because of the assumption that interventions encourage recklessness. It’s time we put this assumption to rest.