Study tested how many people in a group have to change their mind before everyone else turns.
Once 25 percent of the people in a group change their minds, this is enough to convince the rest.
From sexual harassment, social media, gun laws and gay marriage, opinions could reach a tipping point if just one-quarter of participants take a new view.
The finding — published in the journal Science — suggests a majority is not required for society at large to change.
It is even possible for just one person to make the difference.
Dr Damon Centola, the study’s first author, said:
“When a community is close to a tipping point to cause large-scale social change, there’s no way they would know this.
And if they’re just below a tipping point, their efforts will fail.
But remarkably, just by adding one more person, and getting above the 25% tipping point, their efforts can have rapid success in changing the entire population’s opinion.”
For the study, groups were encouraged to come to a view on a new topic.
Then the scientists tested to see how many people opposing this view would be enough to change everyone’s mind.
Dr Centola said:
“What we were able to do in this study was to develop a theoretical model that would predict the size of the critical mass needed to shift group norms, and then test it experimentally.”
The study, though, did not test strongly entrenched beliefs established over decades, which may be more difficult to change.
Still, Dr Centola said:
“Our findings present a stark contrast to centuries of thinking about social change in classical economics, in which economists typically think a majority of activists is needed to change a population’s norms.
The classical model, called equilibrium stability analysis, would dictate that 51% or more is needed to initiate real social change.
We found, both theoretically and experimentally, that a much smaller fraction of the population can effectively do this.”
The study was published in the journal Science (Centola et al., 2018).
