There's a fascinating new explanation for why fake news goes viral

A few days after Donald Trump was elected, 35-year-old Eric Tucker saw something suspicious: A cavalcade of large white buses stretched down main street near downtown Austin, Texas.

Tucker snapped a few photos and took to Twitter, posting the following message:

Tucker was wrong — a company called Tableau Software was actually holding a 13,000-person conference that day and had hired the buses. But as the New York Times noted last year, it hardly seemed to matter.

The erroneous post got shared more than 350,000 times on Facebook and 16,000 times on Twitter, mostly by right-wing Americans drawn to the idea that people on the left had orchestrated an anti-Trump conspiracy. Trump even appeared to join in:

Tucker subsequently acknowledged his error in a new tweet. But a week later, the truthful post had only gotten retweeted 29 times, according to the debunking website Snopes.

Why did the false tweet get so much more attention? A new study published June 26 in the journal Nature looks into why fake posts like Tucker's can go so viral.

Economists concluded that it comes down to two factors. First, each of us has limited attention. Second, at any given moment, we have access to a lot of information — arguably more than at any previous time in history. Together, that creates a scenario in which facts compete with falsehoods for finite mental space. Often, falsehoods win out.

Diego F. M. Oliveira tested this idea by creating a theoretical model for the spread of information. The model was loosely based on epidemiological models that public health researchers use to study the spread of disease. Oliviera's team had bots or "agents" produce messages containing new memes — essentially fake news — on sites like Twitter, Tumblr, and Facebook, and re-share messages created or forwarded by their neighboring bots in a network.

"Quality is not a necessary ingredient for explaining popularity patterns in online social networks," Oliveira wrote in his paper, adding, "Paradoxically, our behavioral mechanisms to cope with information overload may ... increas[e] the spread of misinformation and mak[e] us vulnerable to manipulation."

In other words, the study suggests that most people only focus on real news for short amounts of time, so adding fake news to the mix leads to more competition for our attention. Every few minutes, we make quick decisions about which facts to accept and which to discard. In the process, we may end up disregarding factual information simply because there is so much of it out there.

According to the authors of the study, the fact so many people get news from their social media feeds could also make it harder to distinguish truth from fiction. It's tough to vet the source of a social media post, and a recent study suggests that people base their evaluation of a piece of information more on the person who

Those who saw Eric Tucker's tweet about the buses had no way to know whether the vehicles in Tucker's photos were actually linked to anti-Trump activity.

“I’m ... a very busy businessman and I don’t have time to fact-check everything that I put out there, especially when I don’t think it’s going out there for wide consumption," Tucker told the Times.