How and why does misinformation spread?

According to behavioral models, exposure to misinformation increases the odds that people will believe it, which in turn increases the odds that they will spread it. At the same time, people do not necessarily need to believe misinformation in order to spread it; people may share information they know is false to signal their political affiliation, disparage perceived opponents, or accrue social rewards. Psychological factors contribute significantly to this process: People are more likely to share misinformation when it aligns with personal identity or social norms, when it is novel, and when it elicits strong emotions.

Misinformation spreads differently on social media than on legacy media such as television, radio, and newspapers. Mainstream news outlets tend to have robust safeguards in place to prevent and correct false claims, but several unique features of social media encourage viral content with low oversight. Rapid publication and peer-to-peer sharing allow ordinary users to distribute information quickly to large audiences, so misinformation can be policed only after the fact (if at all). “Echo chambers” bind and isolate online communities with similar views, which aids the spread of falsehoods and impedes the spread of factual corrections. This problem disproportionately affects individuals who consume content from conservative political sources.

Algorithms that track user engagement to prioritize what is shown tend to favor content that spurs negative emotions like anger and outrage. Overall, most online misinformation originates from a small minority of “superspreaders,” but social media amplifies their reach and influence.