Easy. Just make the experience of online political debate so disjointed, impersonal and unpleasant that people shut themselves up. Or they hide out in groupings where everyone says much the same thing. In that case, what they're doing is cheerleading, not debating.
The "spiral of silence" is a theory that people hesitate to say things they believe others in their group won't agree with. It predates the Internet age.
Let me add that the "spiral of silence" disproportionately affects the shy, the thoughtful and the female.
Social media were supposed to free these cooped-up opinions by offering new venues for speaking one's piece. But this high-minded promise of a vast online town hall for pensive argument has fallen flat, according to a new report by Pew Research Center and Rutgers University.
If anything, people seem less willing to engage in real back-and-forth about public affairs on websites than they are in old-fashioned personal settings, the researchers found.
We're talking about politics here, not hiking trips, kitchen renovations and dog adoptions. And the politics we're talking about is not a rally for Sen. Foghorn — the sort of thing that works well online — but a real hashing out of political differences.
To find out how the public ranks social media as a place for political debate, the researchers asked questions about Edward Snowden's leaks of the National Security Agency's operations. They used this issue because polls found the public fairly divided on the subject.
Only 16 percent of respondents who use Facebook said they'd discuss it there. And only 14 percent of those on Twitter said they'd talk about it on Twitter.
But 40 percent said they'd be willing to debate the matter at a family dinner table and 32 percent at a restaurant with friends.
Why aren't we doing more political interchange online? For starters, the Web fragments us into bands of the like-minded. People with minority views can huddle with others holding the same views, making them feel safer, part of a majority.
Further, online interaction is notoriously devoid of restraints on anti-social behavior — doubly so when creeps hide behind fake identities or go anonymous. Not everyone can laugh at "You are an idiot." And for the vulnerable, squads of lowlife trolls can multiply the hurt.
Here's another possible reason for social media's poor showing as a stage for political debate. How can anyone engage in a serious discussion on Facebook with videos of goats nuzzling monkeys cluttering the feeds, alongside pix of weddings and kayaks?
As for Twitter, how can anything more complicated than the temperature in Chicago be discussed in 140 characters or fewer? What passes on Twitter for political debate is often a battle of links. People offer a link to a longer article or post and then add only a handful of their own words, such as "I agree" or "This guy is right" or "You're wrong, read this."
According to the Pew-Rutgers report, people weren't even using social media for basic information about the Snowden-NSA conflict. Almost 60 percent said that television/radio was one of their sources. Some 34 percent said they used online sources other than social media — mainly the sites of mainstream news organizations, I bet. Only 15 percent sought knowledge on the issue through Facebook, and a mere 3 percent used Twitter.
It all sounds paradoxical, but here we have it: Noise only increases the silence on things that matter to our society.