Moving the vaccination needle: Study examines behavioral tactics that work—and don't

Syringe injection vaccine needle
Behavioral researchers at ZS studied vaccine-hesitant people across seven countries, identifying triggers and biases around what makes them tick.(Pixabay)

One of the big questions today is how to get more people vaccinated. Should you offer free stuff? That works sometimes. Remind them that they’re good parents? That actually doesn’t work.

It turns out that not getting vaccinated is pretty irrational, thanks to human beings’ cognitive biases.

Marketers often try to overcome cognitive bias by using behavioral interventions to temper the personal subjective realities that behavioral scientists label with fancy handles like "confirmation bias" or "loss aversion."

But when it comes to vaccinations, which interventions work and which don't?

ZS researchers wanted to find out. So they put 19 different behavioral interventions for cognitive biases to the test. They surveyed three different groups of vaccine-hesitant people—those who were wary about COVID-19 vaccines, adult vaccines or pediatric vaccines, Jacob Braude who leads the applied behavioral science team at ZS said.

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The result? Only 10 of the 19 tactics worked. Seven worked for COVID vaccine-hesitant people, four for those worried about adult vaccinations and five with pediatric concerns. While some tactics worked across one or two of the vaccine-hesitant groups, only one behavioral intervention worked across all three groups.

Confirmation bias, which has been getting a lot of media attention recently in the context of politics, was the only successfully mitigated behavior in ZS’ study of more than 6,300 vaccine-hesitant people across seven countries.

What is confirmation bias? In general, it’s the tendency by people to favor or overvalue information that supports what they already think and to ignore contradictory information. So if a person believes vaccines aren’t safe, they can and will find media, data and reports that support that belief.

Knowing that confirmation bias is likely rampant in the vaccine-hesitant group, ZS didn’t test for it, but they did try a mitigation tactic.

Researchers told people that they understood the person doesn’t want a vaccine but asked them to think about reasons why other people might want to get vaccinated. After the test subjects went through the mental exercise using their own thoughts and words, ZS researchers asked if they were interested in getting vaccinated. And some said yes.

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Overall, 10% more people said they would get vaccinated when compared to the baseline group. Among men under age 50, the jump was even higher with 22% changing their minds.

“Often we see people trying to persuade by saying ‘OK, here are the facts. Here’s why you should get vaccinated,’ ” Braude said. “But this research says actually what you should say is ‘OK, why would someone want to get vaccinated?’ and have them go through the process in their own words. That works much better than the persuasion techniques we see people trying to use.”

Another behavioral tactic springing up around COVID vaccination drives is prospect theory. States giving out prize money, or as they are in West Virginia, chances to win trucks and shotguns, are using a winning tactic.

Other behavioral intervention tactics that worked for COVID vaccine hesitators were effort justification (I put a lot of effort into something so it’s valuable, even if it’s not) and social facilitation (if people know others are watching them, they will behave more pro-socially).

What about other tactics being used? Celebrity endorsements, for instance, probably work—right? Nope, not according to ZS’ study.

Researchers asked people to name any celebrity or public figure who they believe to be a credible authority. The answers ranged widely—some people in the U.S. chose controversial Fox opinion show host Sean Hannity—but the result was always the same.

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ZS tested the participants by repeating back the same credible authority they named along with a second choice of someone the participant said was not credible and said these people recommend getting vaccinated. The test subjects’ response? No thanks—even when the recommendation came from the exact credible authority they chose.

Interestingly, that doesn’t mean all recommendations don’t work. Among vaccine-hesitant parents in the pediatric study group, something called in-group bias did work. The bias is the tendency to go along with people you like and agree with and consider to be in your group more often than you would agree with people outside your perceived group. When told that people in their group are getting their kids vaccinated, they were more likely to also do it, Braude said.

The tricky part of individual bias is just that, they’re individual.

“The way biases work is that every person has a different set of mental shortcuts,” Braude said. “The goal is to layer these bias triggers in a way to try to drive vaccinations. If we look at all of the individual responses, we got anywhere from 20 to 44% of people who started the survey saying they wouldn’t get vaccinated to change their mind.”

Braude acknowledged it is a study but added while the results may be less in the real world “even half, I would take that. If we could get 20% of people to get vaccinated who previously wouldn’t, I would take that in a heartbeat.”