The approval of the first Covid-19 vaccine in the US was celebrated over the weekend as the beginning of the end of the pandemic. However, the road between giving off the first doses and getting widespread vaccination at rates that inhibit the spread of the coronavirus is far from easy. In addition to the logistical challenges of distributing the vaccine, people also need to be ready to take it. A new poll found that more than a quarter of Americans hesitate.

Two prominent economists, N. Gregory Mankiw and Robert Litan, and politicians John Delaney and Andrew Yang have proposed or supported paying Americans for the vaccine. At first glance, this seems like a reasonable idea; The economy teaches us that people respond to incentives. However, behavioral research suggests that this strategy could backfire.

Humans do not respond to incentives like rats pull levers for food. You are trying to interpret what it means to be offered. In this case, there is a risk that the vaccine will not be a valuable asset.

Studies cited in an article titled “Tom Sawyer and the Construction of Value” (referring to a famous section in the Mark Twain book where Tom convinces his friends that whitewashing a fence is a desirable activity ) have found that people are unsure whether something is good or bad, the prospect of payment helps them make negative decisions.

In one of the studies, a professor asked his students if they would attend a reading of Walt Whitman’s Leaves of Grass, and offered half of the students payment to attend the reading while the other half asked if they would would pay to attend. Those who were offered payment reported less interest in participating. For those who are unsure of whether to get vaccinated, like those who are unsure of whether to attend the poetry reading, paying will most likely send the message that this is something you are not want to do without compensation.

It’s also likely that people will conclude from the payment that the vaccine could be risky. In our research with Kevin Volpp and Alex London, we found that people naturally assume that payments are a risk. In a series of experiments, we have described clinical studies that offered different payment amounts for participating in a study with an unfamiliar test procedure. We found that when the payment was higher, people believed that the risk of a study was greater, even though the descriptions of the study procedures were otherwise identical. Paying people to be vaccinated could also lead them to conclude that it is riskier than they would otherwise assume.

Data so far suggests that Pfizer and Moderna’s early Covid-19 vaccine candidates are safe and effective – evidence that has already led to the Pfizer candidate’s emergency approval. Although direct payments for vaccinations could increase acceptance for some people in the short term, the effects just described could ultimately produce the exact opposite of the intended effects, especially for those unsure whether the risks of vaccination are outweighing the benefits.

Payments not only make the vaccine appear riskier, but they may also reduce the likelihood that people will be vaccinated for the selfless goal of helping others. Research shows that paying people for altruistic measures often backfires. In one study, Israeli students who raised for charity on a given day of the year raised less money than they were paid a small commission.

The report on the study, entitled “Pay Enough or Not Pay at All,” argued that the amount paid was too little to motivate students but enough to ask questions about students’ motives for doing have raised a lot of money in the minds of the people watching these students, and possibly even on the part of the student collectors themselves. The same logic would suggest that paying people for vaccination might decrease the motivation of those who are or like to be altruistic would do.

A more promising approach might be to make desired activities such as travel dependent on vaccination. Australian airline Qantas reports that it and other airlines are considering making vaccination compulsory for international air travel. When vaccination is associated with positive results, such as B. Travel and access to large public events, the vaccination itself is rated positively. When people see the various benefits of vaccination, skepticism will likely go away for at least some.

Ultimately, the circumstances surrounding the introduction of the vaccine can affect attitudes towards it. Given the complexities of making and distributing the vaccine, it is almost certain that it will be in short supply for months. The silver lining is that much research in marketing has shown that scarcity can be a huge demand stimulator. Seeing others want to be vaccinated and desperately waiting to get to the top could increase the likelihood that people will see the value of the vaccine and want it for themselves.

George Loewenstein is the Herbert A. Simon Professor of Economics and Psychology at Carnegie Mellon University. Cynthia Cryder is an Associate Professor of Marketing at Washington University’s Olin Business School in St. Louis.