How Narratives Spread

Stories Spread Like Viruses

One of Robert Shiller’s most original contributions to Narrative Economics is the insight that economic stories spread in patterns strikingly similar to epidemics. This is not just a poetic metaphor. Shiller argued that the mathematics of disease transmission can be meaningfully applied to the spread of economic narratives, and the parallel holds up better than most economists expected.

The SIR Model: Epidemic Dynamics of Narratives

Consider the SIR model from epidemiology. A population is divided into three groups:

• S (Susceptible): People who have not yet been exposed to the virus but could be infected. In narrative terms, these are people who have not yet encountered a particular economic story.
• I (Infected): People carrying the virus and actively transmitting it to others. These are the people who believe a narrative, act on it, and actively share it with those around them.
• R (Recovered): People who have recovered and no longer transmit the virus. In our context, these are people who have grown tired of the narrative or turned skeptical.

The speed at which a narrative spreads depends on the balance between the transmission rate (how infectious it is) and the recovery rate (how quickly people lose interest). When transmission outpaces recovery, the narrative grows exponentially. When the balance reverses, the narrative fades.

The R0 of Narratives: What Makes a Story Contagious?

Just as viruses have a basic reproduction number (R0), narratives have characteristics that determine their contagiousness. Drawing from Shiller’s work and subsequent research, highly contagious narratives share common traits.

Simplicity: “AI is stealing your job” spreads ten times faster than “technological innovation is accelerating structural transformation in the labor market, potentially reducing demand for certain occupations.” Complex truths cannot compete with simple stories.

Emotional intensity: Fear and greed are the most powerful transmission vectors. “Inflation is destroying your savings” triggers an immediate emotional response. People are dramatically more likely to share a story when they are emotionally activated.

Identity confirmation: The framing of “retail investors versus Wall Street” is powerful because it fuses with personal identity. Narratives that confirm your worldview are not just information — they become expressions of who you are, which drives compulsive sharing and repetition.

Media and Social Media Amplification

Shiller emphasized the role of social media even when writing Narrative Economics, but the reality of the 2020s has exceeded even his expectations.

The 24-hour news cycle: Financial news channels never sleep. Once a narrative appears, it is endlessly reproduced through panel discussions, breaking news tickers, and expert interviews. A single question — “Will the Fed cut rates?” — is repeated in dozens of variations throughout a single broadcast day.

Social media echo chambers: Algorithms show you what you want to see. If you engage with a post claiming “Bitcoin is going to $100,000,” the algorithm serves you more of the same while suppressing contrary views. The narrative gets locked in a self-reinforcing loop.

Expert authority: Statements from prominent economists, fund managers, and CEOs lend authority to narratives. “Elon Musk said…” functions as an accelerant for narrative spread regardless of whether what he said makes economic sense.

Narrative Mutation

Just as viruses mutate, narratives mutate. The same core story evolves into different forms depending on the environment it encounters.

Track the mutation of the inflation narrative. In 2021, it began as “inflation is transitory.” That mutated into “inflation is becoming entrenched,” which evolved into “stagflation is coming,” and in some corners mutated further into “this is the beginning of hyperinflation.” Each variant triggered different policy responses and different investment behavior.

The mutations are not random. They follow the path of maximum emotional engagement. “Transitory inflation” is boring. “Stagflation” is alarming. “Hyperinflation” is terrifying. Each mutation ratchets up the emotional stakes, which increases contagiousness.

The Lifecycle of a Narrative

Economic narratives follow a relatively predictable lifecycle:

1. Birth: A new economic event or data point plants the seed of a story
2. Viral spread: The story races through media and social networks, beginning to influence markets
3. Peak: Everyone is telling the same story; it dominates the news cycle and market commentary
4. Fatigue: People grow tired of the story, or contradicting evidence accumulates
5. Dormancy: The narrative recedes into the background but does not fully disappear

The critical phase is the last one. A dormant narrative can reactivate at any time when it encounters the right trigger. The “inflation” narrative has gone through multiple cycles of dormancy and reactivation over the past century. It never truly dies; it just sleeps.

Case Study: The “Fed Pivot” Narrative Waves

From 2022 through 2024, the “Fed pivot” narrative generated multiple distinct waves. In the second half of 2022, early signs of inflation cooling created the first wave: “Rate cuts are coming soon.” Markets rallied. Then strong employment data triggered a mutation: “Not yet.” Markets fell back.

The same pattern repeated through 2023. Each time inflation data showed even marginal improvement, the “this time it’s the real pivot” narrative reactivated, and markets surged on anticipation before reality forced a correction. The same narrative cycled through like seasons, moving trillions of dollars in asset values each time.

RETIC attempted to call the turning points of this narrative multiple times. Honestly, we were wrong more often than we were right. But the exercise taught us something valuable. Understanding the spread pattern of a narrative is not about predicting the market — it is about understanding, in real time, why the market is moving the way it does. Our prediction accuracy may be modest, but the depth of understanding is genuinely different.

What This Means for You

Knowing that narratives spread like viruses changes how you consume financial media. The next time you notice every headline telling the same story, every pundit drawing the same conclusion, every social media feed echoing the same fear or excitement — recognize that you are watching an epidemic in progress. The narrative may be correct. It may also be reaching peak infection, with recovery (and reversal) not far behind.

You cannot inoculate yourself against narrative infection. We are all susceptible. But you can develop awareness of the symptoms, and that awareness is the difference between being carried by the current and at least knowing which direction you are drifting.