RACHEL MARTIN, HOST:
When President Trump tweets, the world listens. And when the tweets have an angry tone, they move through the media ecosystem like an electric current, infuriating some while delighting others. People who study social media are starting to draw some early conclusions about how all this works. So next up in our civility series, here is NPR's Tim Mak on Trump and Twitter.
TIM MAK, BYLINE: There's something called the Trump Twitter Archive, which compiles a list of his tweets insult by insult - loser, 260 times; dumb or dummy, 242 times; stupid, 201 times. There are hundreds and hundreds of examples of Trump's mean tweets.
But let's look at a recent pair, where he bashed the late Senator John McCain, who passed away last year. In one tweet, Trump said McCain was last in his class at Annapolis. He wasn't. And in another tweet, he took a swipe at McCain's stance on a health care bill. The tweet storm was then amplified on cable news.
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TARA PALMERI: It's not the first time Trump has bashed the celebrated veteran.
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ANDERSON COOPER: And that's the president attacking a dead war hero for his vote on a health care bill as he himself was valiantly fighting terminal cancer. Consider that for a moment
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BRIAN WILLIAMS: Many people openly questioning the president's sense, his state of mind.
MAK: Sociologist Chris Bail leads the Polarization Lab at Duke.
CHRIS BAIL: We've created a situation in which our political leaders are rewarded for that kind of behavior, both from their bases and their electorate, but also from, you know, social media platforms and also, to some degree, from the media as well.
MAK: And there's growing evidence that incivility and negativity on social media can spread. It's called emotional contagion.
BAIL: And we've seen, generally, that, you know, an emotional post that gets an emotional response gets a kind of multiplier effect that really begins to cause things to scale dramatically.
MAK: We wanted to see if Trump's tweets followed the same pattern. There's been very little academic research on the effect of Trump's Twitter feed. So we asked Bail to help us run the numbers. Evaluating more than 3,000 tweets from Trump and using an automated process called sentiment analysis, Bail found that the more negative the tweet, the more often it gets retweeted. Bail did warn, however, that these are just preliminary findings and a lot more study is needed.
We wanted to see if another lab would have similar results, so we reached out to Clemson University's Social Media Listening Center. Students there manually categorized 1,000 Trump tweets from December to April, sorting them as negative, neutral or positive tweets.
DARREN LINVILL: Trump tweets a lot of negative tweets.
MAK: That's Darren Linvill, the Clemson professor who led that effort.
LINVILL: Slightly more than half of his tweets were negative. About 9 or 10 percent were neutral. And the rest, about 40 percent, were positive.
MAK: Linvill and his team also found that Trump's negative tweets got more retweets, thus grabbing more attention. Linvill thinks that might be because negative tweets have the potential to draw a response from both critics and supporters of the president, whereas neutral or positive tweets may not.
LINVILL: You have people who are angered by that tweet and retweet it while talking about their anger, while attacking back at the president, by saying something perhaps negative in response. And that has the potential, at least, to spread across the entire platform.
MAK: Trump's critics can seize on the ripple effects of his Twitter behavior, saying he's spreading vitriol and setting a horrible example. But his fans embrace this kind of contagion.
Let's go back to Trump's tirade about John McCain. It really crossed a line for a lot of people. But others cheered it on, like Michael Caputo, a former campaign aide to Donald Trump who first met the president in the 1980s.
MICHAEL CAPUTO: His commentary against Senator McCain in life and in death are driven by the fact that John McCain's allies continue to demean Donald Trump. And he will never, ever allow that to happen - not for a moment.
MAK: Caputo says that Trump's Twitter presence has captured a frustration among his most ardent supporters.
CAPUTO: And from all of us out here in flyover country, every time Donald Trump fights back, we feel like he's fighting for us because these people have been tearing us to bits for quite some time now. Not that we encourage the incivility, but until the civility starts on the other side, I don't see any reason why the president should tone it down.
MAK: But ultimately, negativity on social media brews more and more negative behavior. Incivility has a way of spreading, even among people who are normally kind in real life. Christopher Bail, who runs the Polarization Lab at Duke, pointed to one study in which recipients took part in a simulated online discussion.
BAIL: And what the researchers were able to show is that even people who have never engaged in trolling before can begin to show signs of that kind of trolling or uncivil behavior if they're exposed to a broader social context in which that's becoming the norm. And so there's this kind of contagious element to it.
MAK: So when considering Trump's Twitter habits and their effects on how we talk online, the research suggests that leadership matters. When those who have large followings on social media post uncivil or critical things, it does have a cascading effect through the rest of our online conversations.
Tim Mak, NPR News, Washington.
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