“A lie can travel half way around the world while the truth is putting on its shoes.”
Those may be the words of a nineteenth-century English Baptist preacher, but scientific skeptics also know that no debunking of a bizarre claim can ever catch up with the original story. And that’s now especially so in our age of social media.
Scientists from MIT’s Media Lab have documented and quantified this sad truth about the truth in an intriguing new study of the spread of true and false news online. The researchers, Soroush Vosoughi, Deb Roy, and Sinan Aral, investigated the differential diffusion of all the verified true and false news stories distributed on Twitter from 2006 to 2017. Altogether they analyzed the dissemination of 126,000 stories tweeted by around 3 million people more than 4.5 million times. Their study is published in the March 9 Science.
MIT’s institutional review board approved the research, and Twitter funded it and provided access to the data.
The researchers classified the news as either true or false using information from six independent fact-gathering organizations that exhibited 95 to 98 percent agreement on the classifications. They used a broad definition of news. Instead of a more source-based description, they refer to any asserted claim made on Twitter as news.
The result? Falsehood won. Overwhelmingly so. Totally. Without question. “Falsehood diffused significantly farther, faster, deeper, and more broadly than the truth in all categories of information,” they report.
They found that a significantly greater fraction of false cascades of tweets than true cases exceeded a depth of ten—meaning there were ten retweet hops by new unique users from the original tweet over time. Also, “The top 0.01 percent of false cascades diffused eight hops deeper into the Twittersphere than the truth.”
Falsehoods also reached far more people than the truth. The truth rarely diffused to more than 1,000 people, but the top 1 percent of false-news cascades routinely diffused to between 1,000 and 100,000 people. At every depth of a cascade of tweets, falsehood reached more people. This means, say the authors, “that many more people retweeted falsehood than they did the truth.”
Truth took six times as long as falsehood to reach 1,500 people and twenty times as long as falsehood to reach a cascade depth of ten.
The worst type of offender? Political news. “False political news spread faster and farther than false news about terrorism, natural disasters, science, or urban legends,” they report. The total number of false political rumors peaked at the end of both 2013 and 2015 and again at the end of 2016, corresponding to the last U.S. presidential election. There were also peaks during the Russian annexation of Crimea in 2014. Politics became the largest rumor category in their data, with about 45,000 cascades, followed by urban legends, business, terrorism, science, entertainment, and natural disasters.
Why all this? What gives false news so much power? They point to its novel character. “We found that false news was more novel than true news, which suggests that people were more likely to share novel information.” True stories may have inspired anticipation, sadness, joy, and trust, but the false news inspired “fear, disgust, and surprise in their replies.” Those reactions apparently prompt more sharing.
The authors carried out a number of tests of novelty that support their conclusion. “Although we cannot claim that novelty causes retweets or that novelty is the only reason why false news is retweeted more often, we do find that false news is more novel and that novel information is more likely to be retweeted” (p. 1149).
What about automated bots? “We conclude that human behavior contributes more to the differential spread of falsity and truth than automated robots do,” say the authors.
Understanding how false news spreads is the first step toward containing it, they note. “We hope our work inspires more large-scale research into the causes and consequences of the spread of false news as well as its potential cures.”
- See also the Policy Forum “The Science of Fake News,” by David Lazer and fifteen other researchers in the same issue of Science.