The more you think you know about your Facebook friends' opinions, the less likely you are to speak out online. (Dado Ruvic of Reuters)

In the age of social media, it may seem like everyone has an opinion to share on the latest news of the day. But a new study released Tuesday by the Pew Internet and American Life Project has revealed that, in fact, there may fewer opinions on your feeds than you think.

Last summer, researchers from Rutgers University and Pew asked 1,800 American adults how likely they were to speak out, online and in person, about the news that former National Security Agency contractor Edward Snowden leaked information regarding domestic surveillance to media outlets. They found that while 86 percent of Americans would be willing to have a conversation about the issue in person, just 42 percent of Facebook and Twitter users were willing to post about it on those platforms.

The study also found that peer pressure on these sites is alive and well. If people thought their opinions would be well received, they were more likely to post about the topic. But even the thought that some of their followers and friends might disagree led many to self-censor. And the more information people had about the diversity of opinions on their social networks, the less likely they were to speak up, the study found.

That unwillingness to speak up also transferred to the real world. Facebook users were half as likely to voice their opinions in a public setting if they thought their friends on the network disagreed with them. Those on Twitter were 0.24 times less likely to do the same. Users on Instagram, where the study found people tend to have the most awareness of the diversity of their social networks,were 0.49 times less likely to even be willing to discuss the issue with their own families at dinner.

Hampton said these findings could add a new twist to the old communication theory of the "spiral of silence," which says that people who have an minority opinion are less likely to speak up about it. But this study, Hampton says, indicates that maybe users don't even have  to feel as if they are in the minority -- only that there is a certain amount of disagreement within their social circles.

He found that a bit troubling, as a media scholar. "We like to think, as people who care about media, that it would be best if everyone knew everything, and there was perfect information flow," Hampton said. "But this suggests, oddly, that...if we find out there is diversity there, that may be somewhat jarring."

The Snowden leaks have been a particularly sensitive subject for many, but Pew Internet Project director Lee Rainie said that the study's findings fall in line with other research the group has done into the effects social media have on conversation. And, at the time the study was conducted, the general public still new very little about the scope of the surveillance, and participants not yet begun to adjust their online behavior.

"Other Pew Research at the same time shows a lot of people were talking about this stuff," he said. "We don't think people were adjusting their behavior because of the story itself -- it was too ubiquitous."

Of course, there are always people who are willing to speak out on these subjects -- people with passionate feelings about topics, who have a lot of knowledge about them or who just have a natural proclivity for speaking their minds. But the tone cast by those who do speak out appears to have an incredible influence on the rest of their social networks  --  as if the intense peer pressures of middle school and high school are following us well into adulthood.

That assessment may not be off-base, Hampton said. The rapid rise of technology has let us keep in touch with people from parts of our lives that we would have left behind -- high school, college, old workplaces -- but now stay with us, to an extent, regardless of our location. "It hasn't been like that for a long time, since small-town rural life was the norm and we were born, raised and died in the same place," Hampton said.

These findings, of course don't negate the idea that social media networks are a new and important tool for communication. "We're looking at one specific social phenomenon," Hampton said. The ability to use social media for other conversation, research or to find career resources is still an important one, he said.

This study does, however, seem to expose a "darker side of that same equation," he said. "For political deliberation and how it impacts offline deliberation, social media is not so good, or at least not doing as much for those conversations as we had hoped."