From Herd Immunity to Herd Mentality: Why Vax-a-Million is Working

The US vaccination goal has shifted from herd immunity to simply getting as many needles in arms as possible. But the underlying obstacle remains the same: how do you persuade people to get the shot?

In recent weeks, vaccine incentive programs have bubbled up all over the country, but few have garnered the attention of Governor DeWine’s “Vax-a-Million” lottery. Last Wednesday, Abbigail Bugenske (age 22) won the first of five million-dollar prizes and Joseph Costello (age 14) won a full-ride scholarship to college. While critics remain, the Associated Press analysis concluded the state vaccination rate is up 33% since the announcement. President Biden endorsed Ohio’s program last week, and other states have begun similar lotteries.

Originally I was skeptical of the Vax-a-Million lottery. I argued to put $100 in the pocket of every newly vaccinated person because people usually prefer a sure thing over some chance of a larger payout. But Governor DeWine leveraged another aspect of prospect theory, namely that individuals tend to overweight low probabilities. That is why we buy insurance, go to casinos, and play the lottery to begin with. Governor DeWine simply applied this behavioral trait to his vaccination strategy. And, perhaps unwittingly, he employed an additional persuasion tactic—he generated ‘social proof’.

Social proof, a term coined by Robert Cialdini, suggests that people alter their behavior to be more like people around them. Imagine it is your first day at a new job. You are in jeans and everyone else is wearing a suit. What will you wear tomorrow? Not only do humans have an innate desire to fit in with others, we are more receptive to suggestions if people similar to us have already engaged in that behavior. That is why we ask friends for Netflix recommendations and visit Tripadvisor before planning a vacation. We seek the advice of others because we think we will like what they like.

Social proof is more effective when the desired behavior is observable. For instance, people are more likely to wash their hands when others are watching. This is one reason social proof was a useful persuasion tool with mask-wearing. Even people who didn’t ‘believe in’ masks wore them to not stand out from the group. But vaccines are invisible. Sure, you can get a sticker or button, but there is less social pressure to conform to the group because there is no visible proof that the group exists.

The genius of the Vax-a-Million lottery is that it manufactured its own social proof by leveraging social media. Every article about the program has hundreds or thousands of comments pushing the dialogue toward vaccination. Not all are positive, but there is a chorus of “I got my shot and feel so relieved!” and “My whole family is fully vaccinated!” Giving space for these comments creates a public forum where people can observe the group mentality. It underscores that many people—your friends, neighbors, fellow Ohioans—are engaging in the same behavior to achieve a shared goal.

How do we maintain this momentum and offer more social proof to those still on the vaccine fence? It could be as simple as changing the headline. Instead of highlighting the number of people who have not received the vaccine, focus on the percentage who has. With more people getting vaccinated every day, this group continues to expand, and the desire to be a part of it will too.

[This piece was originally published in the Columbus Dispatch.]