Millennials are taking online positions on the economy, foreign affairs, taxes and immigration. They are declaring opinions about global warming, income equality, abortion rights and other issues. They often find themselves in agreement — but that’s not necessarily a good thing.

The younger generation is dominating political conversations on social media. Nearly half of millennials share content about politics, which is 2.4 times as much as the general population. Thirty-three percent shared information on the midterm elections, which was 112 percent more than the rest of Americans, according to ShareThis, which recently analyzed information shared by 210 million individuals by using data collected from USAToday, the Daily Beast and CNN Money.

“Social media is allowing millennials to become more proactive in expressing their opinions,” says Mark Frydenberg, senior lecturer of Computer Information Systems at Bentley University. “It has enabled students to become more socially aware.”

Younger users are more likely to post their own thoughts about issues, post links to political material, encourage others to take political action, belong to a political group on a social networking site, follow elected officials on social media, and like or promote political material others have posted, according to a 2012 Social Media and Political Engagement study from the Pew Research Center.

The issue is that the vast majority of millennials have adopted online political stances that mirror those of family and friends. And concerned analysts are now asking: Do young people surround themselves with others who think like them and hesitate to say anything different? The answer is yes. And they are not alone.

Social media sites like Twitter and Facebook are leading millennials to shy away from expressing contrary opinions about public affairs, according to a recent report from the Pew Research Center and Rutgers University. People of all ages are less likely to voice their opinions online, especially if friends do not share them. They are also more reluctant to express dissenting views in the offline world.

“People who use social media are finding new ways to engage politically, but there’s a big difference between political participation and deliberation,” says Keith N. Hampton, an associate professor of communication at Rutgers and an author of the study.

“People are less likely to express opinions and to be exposed to the other side, and that’s exposure we’d like to see in a democracy,” he adds.

In the pre-Internet era, Pew researchers uncovered a “spiral of silence,” which was shorthand for their surprising insight about human behavior: People have a tendency to keep quiet about policy issues when they believe their viewpoints are not widely shared among family, friends and work colleagues.

Pew launched a 2013 survey of 1,800 adults to discover if that silence had lessened with social media. It turns out the opposite is true. People with minority views are even more inhibited about expressing opinions on social platforms like Facebook and Twitter. Eighty-six percent of Americans said they’d be willing to discuss a divisive public policy issue in person — but only 42 percent of Facebook and Twitter users said they’d post about it, according to researchers.

Social media users were also less likely to share their opinions in face-to-face settings, especially if they didn’t feel their online friends agreed with them. For instance, the average Facebook user was half as likely as other people to say they’d be willing to share their opinion with friends at a restaurant, according to Pew. The report concluded that social media does not provide new forums for the hesitant to draw new perspectives into discussions of political issues.

“The broad awareness social media users have of their networks might make them more hesitant to speak up because they are especially tuned into the opinions of those around them,” said researchers.

According to an extensive study by Niche, a research group that surveyed 20,000 millennials, many of them — 65 percent — like to read other people’s opinions on Facebook, but these postings rarely change their minds. Eighty percent reported they have never changed an opinion after reading a politically charged post on a social network, according to researchers.

“Social media like Twitter and Facebook can create an echo chamber in which people are exposed only to opinions in line with their own,” states an opinion piece in the New York Times.

In many ways, millennials are not making political choices for themselves. The Web massively influences the way they get their news in the first place. Ninety percent of millennials browse the Web for information on government and politics, according to the ShareThis study.

“We live in the Digital Age,” says Frydenberg. “Millennials are getting their news from Twitter and Facebook.”

Unfortunately, say analysts, millennials seeking news online are surrounded by information and opinions designed for people just like them.

For instance, Facebook now has a fifth of the world — about 1.3 billion people — logging on at least monthly. It drives up to 20 percent of traffic to news sites, according to figures from the analytics company SimpleReach.

But Facebook hides stories with headlines a millennial user might dislike by burying them in the news feed — the stream of updates, photographs, videos and stories they see. Twitter shows them tweets from people they don’t even follow but their friends do.

Humans are acutely attuned to the approval of others, constantly reading cues to judge whether people agree with them, Pew researchers have found. Active social media users get many more of these cues — like status updates, news stories people choose to share and photos of how they spend their days — and so they become less likely to speak up.

“The Internet, it seems, is contributing to the polarization of America, as people surround themselves with people who think like them and hesitate to say anything different,” says a New York Times article, “How Social Media Silences Debate.”

The traditional view of the spiral of silence is that people choose not to speak out for fear of isolation. But other Pew Research studies have found that it’s common for social media users to be mistaken about their friends’ beliefs and to be surprised once they discover their friends' actual views on social media. 

Millennials have been called Generation Nice. Time to drop that for now. A lot more healthy disagreement will do us all good.