Fake news has always been with us, from stories in the 1800s of people setting foot on the moon to the grocery store tabloids flashing scoops on aliens.
Social media has created a boom in the spread of information, although little is known about how it has facilitated the spread of false information. Roy adds that the researchers were "somewhere between surprised and stunned" at the different trajectories of true and false news on Twitter.
False news moved through Twitter "farther, faster, deeper and more broadly" than the truth, said Sinan Aral, a professor of information technology at MIT who studies social media networks. In fact, the results showed that it takes true news stories six times as long to reach 1,500 users as false news.
"Contrary to conventional wisdom", the researchers wrote, "robots accelerated the spread of true and false news at the same rate, implying that false news spreads more than the truth because humans, not robots, are more likely to spread it". It was real people doing most of it.
"Falsehoods were 70 per cent more likely to be retweeted than the truth", the authors wrote", even when controlling for the account age, activity level and number of followers and followees of the original tweeter".
Unsurprisingly, political content was the most popular, and researchers noted spikes in the spread of false political rumours during both the 2012 and 2016 US presidential elections.
Meyer writes, "The massive new study analyzes every major contested news story in English across the span of Twitter's existence-some 126,000 stories, tweeted by 3 million users, over more than 10 years-and finds that the truth simply can not compete with hoax and rumor".
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I have not seen conclusive evidence that social media is causing political polarisation.
Roy said the study results reminded him of the often-cited quotation that essentially says a lie can travel halfway around the world before the truth can get its boots - or trousers - on. Bots don't talk back, and neither do fake-news-spreading trolls.
"These findings shed new light on fundamental aspects of our online communication ecosystem", says Deb Roy, an associate professor of media arts and sciences at the MIT Media Lab and director of the Media Lab's Laboratory for Social Machines (LSM), who is also a co-author of the study.
While the spread of false news on social media has always had real world consequences - for example, leading to drops in the stock market - the 2016 US presidential election has emerged as a watershed example of how far and wide that influence can reach.
The team used six independent fact-checking sources, including Snopes and Urbanlegend, to identify whether the stories in the study were genuine. About three million people retweeted the claims sampled by researchers - both true, false, and mixed - more than 4.5 million times. "People respond to false news more with surprise and disgust", he notes, whereas true stories produced replies more generally characterized by sadness, anticipation, and trust.
Untrue stories also had more staying power, carrying onto more "cascades", or unbroken re-tweet chains, they found. "What I'm saying is that human beings have more responsibility than we may have thought, and that actually changes the way that we would think about solutions".
"How do you get a few billion people to stop for a moment and reflect before they hit the retweet or the share button", he says, "especially when they have an emotional response to what they've just seen".
But don't forget about the bots, argue Filippo Menczer of Indiana University and colleagues.