How Does Fake News Go Viral?

The Doctor Weighs In
6 min readJul 24, 2017

Do any of you remember what happened on December 4, 2016? Let me jog your memory. On that day a well-meaning, but pathetically ill-informed man burst into a Washington D.C. pizza restaurant called Comet Ping Pong with a military style rifle and a handgun. He used the rifle to fire multiple shots. Thankfully, the bullets did not hit anyone.

The man, Edgar M. Welch, a 28-year-old from North Carolina later said he was on a “humanitarian” mission to “self-investigate” a claim that Hillary Clinton and her then-campaign chief, John Podesta, were running a pedophilia ring out of the restaurant’s back rooms. The conspiracy theory was likely generated by a white supremacy Twitter account before gaining traction across various online message boards and fake news sites leading up to the 2016 presidential election. What caught my interest was not so much the bizarreness of the story nor the stupendous stupidity of people believing and propagating the story. It was the fact that, as Buzzfeed put it,

“Thanks to just a few tweets, a couple of message board posts, and the help of some pro-Trump sites eager for traffic, this conspiracy theory generated hundreds of thousands of engagements on Facebook, reaching potentially tens or hundreds of thousands of people”.

How can such a ludicrous meme go viral?

The spread of epidemics

Epidemiologists and network theorists have been studying for many years how a virus infection with an actual virus “goes viral”. Elaborate mathematical models have been constructed to simulate the spread of the influenza and HIV viruses. Such models proved to be enormously useful in containing the recent Ebola epidemic.

It is not surprising then, that when social scientists studied the spread of ideas or memes in a population, those epidemiological models came to mind. Indeed, there are many common obvious factors characteristic to both. Just as a virus requires contact between two individuals for its spread, so does a piece of information. But, as a recent article in Scientific American points out, “information is not a virus”. For instance, normally a single viral species is involved in causing an epidemic. Not so with ideas. There is no limit to the number of memes that spread through a population at the same time. That has always been thus. But the democratization of creating and spreading information has had a multiplicative effect. How so?

A recent article in Nature Human Behaviour used a mathematical model to examine how news spread on social media. And they came to a surprising conclusion: Fake news doesn’t spread in a population because of some collective stupidity; it is because we are overwhelmed with information. They posit that because available time and attention span are limited, we cannot possibly access and vet the veracity of all the information coming at us. As the computer scientist Filippo Menczer of Indiana University, explains:

“If you live in a world where you are bombarded with junk — even if you’re good at discriminating — you’re only seeing a portion of what’s out there, so you still may share misinformation. The competition is so harsh that the good stuff cannot bubble to the top.”

It sounds plausible to me, but incomplete. What is missing is the human element. It reminds me of the reigning economic theory of Homo Economicus that posits that human behavior is based on the desire to maximize economic advantage. In other words, we are all rational, calculating machines. However, the school of Behavioral Economics points out the many deficiencies in treating humans as rational automatons. We are complex individuals, emotional, biased, prejudiced, altruistic — anything and everything but purely rational. So it is with information. We don’t consume and spread information like computers, spewing out indiscriminately endless strings. Even if we wanted to, there aren’t enough hours in the day to do it. Rather, we pick and choose what to share based on our personal reaction to it.

How do we cope?

I receive and send bits of information to a group of friends that, as it just happens, share my views on a variety of social issues. But, of course, it didn’t “just happen”. We tend to select friends who share our views. It would be highly unlikely that I would establish and maintain a friendship with a white supremacist, for instance. That doesn’t mean that such a person is a priori malevolent. She may be a wonderful mother; he may be a compassionate man or even a war hero. But if he shared racist memes or other information with me targeting President Obama, I would reject it out of hand. This is called “confirmation bias” — we subconsciously accept and internalize information that conforms to our beliefs and reject anything that does not confirm our biases.

It is this very human quirk that makes the mathematical model of information spread inadequate. The meme doesn’t spread evenly among disinterested individuals. It spreads along pre-existing pathways of groups sharing similar opinions, biases, prejudices. This is how hundreds of thousands “knew” about Hillary Clinton and John Podesta running a sex ring of pedophiles weeks before I learned about it when the story about the self-investigator shooting up the pizza restaurant hit main stream media. We are all prisoners of the proverbial “echo chamber”.

Another critical difference between the epidemiological model of virus (the one built of nucleotides) spread and viral (the metaphoric one) spread of information is the phenomenon of herd immunity. As an infectious agent spreads through a population, more and more people who got infected become immune, and progressively fewer people are available targets for further spread. This is how epidemics die out. The opposite is true with information spread. The more people get “infected” with fake information, the more it is repeated, and as Goebbels, the father of fake news, said about propaganda: The secret to making people believe in ‘the Big Lie’ is repetition. Repeat a lie often enough, and eventually people will accept it as fact. I was recently gobsmacked by a well-educated woman friend who was worried that the country is in imminent danger of coming under Sharia law! Where did she get this piece of garbage information? Google “pizzagate” and you will learn how the modern practitioners of Goebbels’ theory accomplished it. No mathematical model exists so far as I know that describes this reality. That makes it doubly hard to combat.

What’s to be done?

The obvious remedy is to open our minds, to listen without judgment, and to think critically. Spending a lifetime in science, where facts are the only things that count, it is at once amazing and dismaying to hear allegedly highly educated people talk about “alternative facts” as a matter of fact. Is it just ignorance, or is it a deliberate anti-intellectual and anti-science worldview? I tend to think the latter, but am I falling into the trap of ‘connecting the dots’ and weaving a conspiracy theory?

Consider these facts:

In its 2012 platform, the Texas GOP opposed the teaching of “higher order thinking skills” because it believes the purpose is to challenge a student’s “fixed beliefs” and undermine “parental authority”. Of course, the platform doesn’t reject wholesale the idea of critical thinking. Evolution? Climate change? We should open our minds to Biblical evidence and faux science:

“Controversial Theories — We support objective teaching and equal treatment of all sides of scientific theories. We believe theories such as life origins and environmental change should be taught as challengeable scientific theories subject to change as new data is produced. Teachers and students should be able to discuss the strengths and weaknesses of these theories openly and without fear of retribution or discrimination of any kind.”

Delivering the coup de grace to the teaching of modern ideas, the party proposed that:

“U.S. Department of Education — Since education is not an enumerated power of the federal government, we believe the Department of Education (DOE) should be abolished.”

Is this an isolated case of a handful of Texans yearning for the good old days? Not quite.

Republican state lawmakers in four more states (Alabama, Indiana, Oklahoma, and South Dakota), many of them adherents of a theological worldview with no basis in science, advanced legislation allowing educators to teach alternative fact-based pseudoscience if they believe it to be scientific.

To paraphrase Everett Dirksen, the legendary Republican majority leader senator in the 60’s (look it up): an anecdote here, an anecdote there, and pretty soon you get a pattern.

So if you’ve ever wondered how could millions of Americans believe the garbage thrown at them on the internet, here is your answer: repeat the lie as often as possible, and keep them stupid enough to believe it.

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Originally published at on July 24, 2017.



The Doctor Weighs In

Dr. Patricia Salber and friends weigh in on leading news in health and healthcare