The rumor started small.
Someone’s relative knew someone who had experienced something troubling. It was shared in a private message. Then it was shared in a group chat. Then someone posted it on social media, slightly embellished. Then it was shared again with more drama. Then a news outlet covered it. Then it became truth.
None of the people sharing it were lying deliberately. At each stage, they believed what they were passing along. The embellishment felt like clarification. The addition of details felt like specification. The amplification felt like emphasis on something important.
But by the time it had traveled through five mouths, it was no longer the original story. It was a story that had been shaped by each person’s emotional response, their social pressures, their desire to make it more interesting.
This is how misinformation works in reality. Not through coordinated campaigns of deliberate deception, though that exists. But through the normal social transmission of information combined with human psychology.
Social contagion is the phenomenon where emotions, behaviors, and beliefs spread through networks like viruses spread through populations. Except it’s not exactly like a virus because the mechanism is different.
When information spreads through direct contact, it mutates. People don’t transmit information with perfect fidelity. They transmit their emotional response to the information. They transmit the aspects that seemed most relevant to them. They transmit whatever details seemed most memorable or shocking.
I started tracking this during the pandemic. A story would emerge. I would see it in its original form. Then I would see it appear in my social feed, slightly altered. Then I would see it in a friend’s retelling, significantly altered. Then I would see it being cited as fact in a discussion, completely unmoored from its origins.
At no point was anyone being dishonest. Everyone thought they were conveying truth. But the truth had been transformed by being passed through human perception.
The research on this shows something called the false consensus effect. People overestimate how many other people agree with them. This is because they spend most time with people who are similar to them. So when they observe agreement in their circle, they assume broader agreement exists.
When this distorted view is combined with social sharing, something dangerous happens. A belief that’s held by a minority of people in a community can appear dominant if that minority is vocal and connected. It spreads because people assume it’s more widespread than it actually is.
Then others adopt it because they think everyone else has already adopted it. This creates a false consensus that accelerates the spread.
The mechanism is emotional, not logical.
Studies on viral content show that the most shared information is information that triggers emotional responses. Outrage spreads faster than nuance. Fear spreads faster than balanced analysis. Righteous anger spreads faster than thoughtful critique.
This isn’t because people are stupid. It’s because emotions hijack attention. Your brain treats emotionally significant information as priority. It spreads it faster. It encodes it more deeply.
When a false idea arrives with emotional charge, it bypasses the critical thinking system. It goes straight to the limbic system. And your brain decides this is important and worth passing along.
I watched this with a conspiracy theory about a public figure. The original claim was vague and unsubstantiated. But it was paired with emotional language about betrayal and hidden agendas. As it spread, people added their own emotional narrative. By the time it had circulated widely, the emotional intensity had become the evidence for the claim itself.
People believed it because everyone was talking about it with such conviction. The conviction came from the emotional charge, not from evidence. But to the person observing all the conviction, the conviction itself felt like evidence.
This is social proof in reverse. Instead of seeing that many people believe something, you see that people believe something with great emotional intensity. And that intensity broadcasts as certainty.
The research shows that correcting misinformation is remarkably ineffective. You can show people evidence that contradicts what they believe. Sometimes their belief strengthens. This is called the backfire effect. The contradiction triggers defensiveness. The emotional investment in the belief is challenged. So they double down.
The original belief is now part of their identity. Admitting it’s false means admitting they were wrong. Admitting they spread falsehoods. Admitting they were fooled. Most people will protect their identity over truth.
I’ve seen this in people I love. They encounter evidence that contradicts what they’ve been saying. Instead of examining the evidence, they attack the source. Instead of reconsidering, they clarify what they meant in a way that’s compatible with the new evidence. Instead of changing their view, they expand it to incorporate the contradiction.
The mind is remarkably good at this. You can find evidence compatible with almost any belief if you search hard enough. The human brain is specifically adapted to defend beliefs it’s already committed to.
The scariest research shows that misinformation doesn’t have to be believed to be effective. Repeated exposure to misinformation, even when people consciously reject it, can increase familiarity. And familiarity breeds acceptance.
This is called the illusory truth effect. When you hear something multiple times, from multiple sources, your brain starts to interpret the repetition as evidence of truth. Even if you’re consciously skeptical about the claim, the sheer frequency of exposure creates a sense of truthiness.
So misinformation spreads through social networks because:
It travels faster when it’s emotionally charged. People assume that if many people are sharing it, it must be true. Contradiction doesn’t work because it triggers defensiveness. Repetition creates truthiness independent of actual truth. People stop fact-checking when they’re emotionally invested.
The result is networks where false ideas genuinely seem true because they’ve been socially validated. Not through coordination, but through the normal operation of human psychology.
The worst part is that intelligent people are not more resistant to this. In fact, they’re sometimes more vulnerable because they’re better at constructing justifications for beliefs they’re emotionally invested in.
The rumor about that relative? I never found out if it was true. It had spread too far. The original story was lost. All that remained was the emotional truth that people had constructed around it. And that emotional truth had become real enough to guide people’s behavior.
That’s the power of social contagion. Not that false things become technically true. But that false things become psychologically true. And people organize their lives around psychological truth.
Citation:
Berger, J., & Milkman, K. L. (2012). What makes content viral? Journal of Marketing Research, 49(2), 192-205.
Sunstein, C. R., Hastie, R., Wiser, M. J., & Schkade, D. (2006). Deliberating about dollars: The severity shift. Journal of Risk and Uncertainty, 30(2), 121-142.
Wood, T., & Porter, E. (2019). The elusive backfire effect: Mass attitudes’ steadfast factual odium. Political Communication, 36(1), 65-80.
DiFonzo, N., & Bordia, P. (2007). Rumor psychology: Social and organizational approaches*. American Psychological Association*.