It has been about a week since the Trump administration recommended that all Americans wear masks, or some face coverings, in public to protect against the spread of coronavirus. But the president himself is still not following that advice.

As he put it, “Wearing a face mask as I greet presidents, prime ministers, dictators, kings, queens — I just don’t see it.”

Why doesn’t he “see it”? To answer that question, let’s ask another one. If you pass a neighbor on the street or in a grocery store, and if he’s wearing a mask, what do you think?

Here are some possibilities:

• He has coronavirus.

• He is far more frightened than he should be.

• He looks weird.

• He is being prudent.

• He is simply following the government’s recent recommendations.

All over the country, people who wear masks are still producing reactions 1, 2 or 3. To be sure, those reasons were more common a few weeks ago than they are now — but they continue to be widespread. Here’s the problem: If you know you’re going to produce one of the first three reactions, you’re less likely to wear a mask, even if it’s a sensible thing to do.

The more fundamental point is that even when they involve health and safety, our actions have “social meanings,” and acting on our own, none of us can change those meanings.

If you were a passenger who buckled your seat belt a few decades ago, the driver might have interpreted it this way: “You are a terrible driver, and I am terrified that we are going to crash.”

If you complained after someone lit up a cigarette in an office meeting in 1965, you would have been perceived as uncool or difficult or weird. You might even have felt you had to smoke, too, just to fit in.

If you declined to eat meat at a dinner party in, say, 2005, you might have seemed like a moralistic oddball — and in many places, that’s true today.

Social meanings greatly affect what we do. Sometimes they have the same effect as fines. If we violate existing norms, and if the meaning of what we do is generally regarded as bad, we will be punished. Sometimes social meanings have the same effect as subsidies. If we comply with existing norms, and if the meaning of what we do is generally regarded as good, we will be rewarded.

A recent example: Before the pandemic, you might have wanted to telecommute once in a while, and succeeded in getting your employer’s permission to do that. But if you thought the meaning of telecommuting was that you were showing yourself to be a slacker, and not really dedicated to your work, you might have felt pressure to go into the office.

Social meanings change over time — often slowly, but sometimes in a hurry. Because these changes usually affect how people behave or act, they might make all the difference: They can cost or save lives.

Social meanings often change because of law. If the law requires people to wear seat belts, the meaning of wearing seat belts suddenly becomes, “I do what the law says.” And when cigarette packages have prominent warnings, and people are banned from smoking in public places, it becomes perfectly acceptable to say: “Would you mind not smoking?”

Social meanings might also change because prominent people, or large numbers of people, are able to get them to shift. If a well — funded educational campaign emphasizes the dangers of drunken driving and the importance of having a “designated driver,” the meaning conveyed by turning down a drink can change pretty quickly.

We have seen massive changes in social meanings over the last many weeks. Declining to shake hands, working from home, washing your hands all the time — a lot of what was perceived as socially acceptable, even expected, behavior has been turned upside down.

Which brings us back to the choice of whether to wear a mask. Officials at the Centers for Disease Control and Prevention are “advising the use of simple cloth face coverings to slow the spread of the virus and help people who may have the virus and do not know it from transmitting it to others.” For the time being, it seems clear that people really should be wearing masks in public settings.

Whether people follow the CDC’s advice depends in large part on the social meaning of doing that. It would have shown real leadership if Trump had announced the recommendation while wearing a mask — or, at a minimum, by saying that he would personally follow the recommendation whenever in proximity to groups of (say) more than 10 people.

But whatever the president does, each of us can contribute to changing the meaning of wearing a mask, simply by doing as the CDC advised — and thus of increasing the likelihood that wearing some sort of face covering will be seen as what most people are doing these days to be good citizens, and to protect themselves and others.

Right now, we need the meaning of precautionary measures to be subsidized by new social meanings. Lives depend on it.

 

Sunstein is a Bloomberg Opinion columnist. He is the author of “The Cost-Benefit Revolution” and a co-author of “Nudge: Improving Decisions About Health, Wealth and Happiness.”