Larry Laughlin, a retired business owner who follows conservative websites: “It’s like a hockey game. Everyone’s got their goons. Their goons are pushing our guys around, and it’s great to see our goons push back.”

The proliferation of fake and hyperpartisan news that has flooded into Americans’ laptops and living rooms has prompted a national soul-searching, with liberals across the country asking how a nation of millions could be marching to such a suspect drumbeat. But while some Americans may take the stories literally — like the North Carolina man who fired his gun in a Washington pizzeria on Sunday trying to investigate a false story spread online of a child-abuse ring led by Hillary Clinton — many do not. The larger problem, experts say, is less extreme but more insidious. Fake news, and the proliferation of raw opinion that passes for news, is creating confusion, punching holes in what is true, causing a kind of fun-house effect that leaves the reader doubting everything, including real news. That has pushed up the political temperature and increased polarization. No longer burdened with wrestling with the possibility that they might be wrong, people on the right and the left have become more entrenched in their positions, experts say. In interviews, people said they felt more empowered, more attached to their own side and less inclined to listen to the other. Polarization is fun, like cheering a goal for the home team. —NYTimes.com