Read our COVID-19 research and news.

Tipping points for social change—such as the acceptance of gay marriage in Australia—have been hard to methodically test.

AP Photo/Rick Rycroft

How minority viewpoints become majority ones

Want to start a trend? The key is to get a committed minority of folks to follow your lead. But how many is enough? A new study suggests marshaling at least a quarter of people in a given population can “tip” the scales of public opinion in your favor. Once your group reaches that threshold, most everyone else will quickly get on board.

The mysterious “tipping point” at which viewpoints rapidly move from minority to majority status—think, the rise of the Nazis in 1930s Germany or the rapid acceptance of gay marriage in the United States—has long fascinated social scientists. Even a trend as benign as fist-bumping has to reach a critical threshold before it is widely accepted. But although past studies have put that number anywhere from 10% to 40%, none of them methodically tested how large groups react to the introduction of new ideas.

Damon Centola, a sociologist at the University of Pennsylvania, set out to do just that. He and his team recruited nearly 200 subjects to participate in an online naming game. In the game, players were shown a picture of a face, for which they were asked to come up with a name. To win, they had to write in the same name for the face as a randomly assigned, anonymous partner. Partners could see the suggested names only after the round ended.

After 10 to 20 rounds—each of which was played with a new partner—people appeared to formulate a “library” of the previously suggested names and started to pick the same ones. Once that happened, the norm quickly caught on in the rest of the group, and strangers who met for the first time would often use the same name. Within 25 rounds in one game, for example, everyone had named their face “Simone.”

Then, the researchers threw in a monkey wrench. They added a new group of people who all had the same agenda: They wanted to name the face “Mary.” In one test, the Mary clique constituted 17% of the total participants. In another test, they made up to 31%. After experimenting with different numbers of people who held this “minority” viewpoint, the researchers discovered their tipping point: When the minority viewpoint made up at least 25% of the population, it was likely to rapidly become the majority viewpoint, the team reports today in Science.

The study suggests personal preference is “not just about what individuals want,” says Emily Erikson, a sociologist at Yale University who was not involved in the work. “There’s this huge social dynamic that changes people’s actions.”

But that doesn’t mean such dynamics will tip any social convention, Centola says. Political orientation, religious beliefs, and opinions about issues like abortion are notoriously intractable. Figuring out how those might tip would take far more—and far more difficult—research, Erikson says. That’s particularly true when the participants don’t have a strong incentive to cooperate.

Arnout van de Rijt, a sociologist at Utrecht University in the Netherlands, agrees. He says the online game in the new study is akin to conducting an experiment in a Petri dish version of the world. He wants to know what would happen if a small or equally sized minority group wanted to protect the status quo. How big would the opposing group need to be to tip the whole shebang? Likewise, Erikson wonders what happens when more than one committed minority is fighting for change. “The outcome very clearly wouldn’t be the same,” she says.

Finally, the real world contains some groups that are far more powerful than others. In the game, all players participated as equals, similar to the way anonymous individuals interact online on message boards and in chat forums. “This is not a story about a small elite with extraordinary resources being able to sway public opinion,” Van de Rijt says. But for him, that’s what makes the findings so powerful. It’s about what a small minority can do with pure, unwavering commitment to an idea, he says.