Recent news offer a variety of topics to be angry about. Here’s one: “After a nearly two-week hiatus, the Lexington, Virginia, restaurant known for turning away White House Press Secretary Sarah Sanders reopened its doors Thursday night.” Chances are, you have used social media to inform your opinion on that topic. And as it turns out, whether you side with Ms. Sanders or the Red Hen, that same social media likely radicalized your opinion, fueling your .

For radicalization researchers, social media offer an interesting observational study. Research on face-to-face groups discovered that discussion among like-minded people radicalizes their average opinion. A group that starts out slightly pro-life ends up more pro-life; a group that starts out anti-guns ends up more so.

Two forces radicalize opinions in group discussion. One is informational: people learn new arguments to support the opinions they already hold. The second radicalizing force in group discussion is social: people admire and want to emulate those expressing the most extreme opinions.

Social media discussions carry both informational and social aspects of group polarization. In news-related Twitter threads, tweets that offer new arguments supporting a particular attitude (useful facts, catchy metaphors, moral judgments) get more “likes” and retweets. Twitter users learn relevant arguments to reinforce their own opinions. Users with more radical opinions get larger followings, precisely because their tweets use expletives and polarizing rhetoric. More radical individuals have more social influence.

Social media are more radicalizing than face-to-face groups because they are larger collectives (more sources of information), and because in these large collectives there is more likelihood of encountering radical individuals. There’s a third reason social media groups are more radicalizing. In a face-to face group, dissenters can be ignored or expelled—but only with some unpleasantness. On a social media platform, selection has no downside; just press the mute button or the block button.

Some cases of social media radicalization have already come to light. The Arab Spring, the Ukrainian Revolution of 2014, and the Armenian revolution of 2018 evolved on social media, where opinions radicalized first, and then action was planned and coordinated. ISIS’ use of social media to recruit fighters, wives, and supporters around the globe resulted in thousands of Western youths travelling to Syria and Iraq. Russia used Facebook and Twitter to try to twist the U.S. electorate with radicalizing posts. Perhaps the most amazing example is the INCEL (involuntarily celibate) movement, which unites losers living in their parents’ basements, and upgrades their personal grievances of sexual failure to the level of a political movement worthy of NYT editorials.

More people every day rely on social media for their news, entertainment and social interactions. What we need is independent research to investigate their potential political effects. Like a Trojan horse, we let these vehicles into our daily lives. Let’s not close our collective eyes to the danger that they can carry.