·Psychology & Behavior
Section 1
The Core Idea
In 1999, Timur Kuran and Cass Sunstein published a paper that explains half of what goes wrong in public discourse: "Availability Cascades and Risk Regulation." The concept is a self-reinforcing cycle. A belief gains credibility simply because it gains repetition. The more people talk about something, the more cognitively available it becomes — it sits at the front of memory, ready to be retrieved. The more available it is in memory, the more people estimate it as common, important, or true. The higher the estimated importance, the more people talk about it. The cycle feeds itself. The belief doesn't need to be accurate. It needs to be repeated.
The mechanism combines three forces. First, the availability heuristic — Daniel Kahneman and Amos Tversky's finding that people judge the probability of events by how easily examples come to mind. If you can quickly recall instances of something, you estimate it as more common than it actually is. Second, social proof — if many people believe something, others infer it must be true, because why would so many people be wrong? Third, media incentives — stories that generate attention get more coverage, which makes them more available in memory, which generates more attention. Each force amplifies the others. Availability makes the belief seem common. Social proof makes it seem credible. Media coverage makes it seem important. The cascade accelerates.
Shark attacks are the textbook example. In any given year, roughly 5-10 people die from shark attacks worldwide. Approximately 450,000 people die from falls. Shark attacks receive thousands of times more media coverage per death than falls. The coverage makes shark attacks highly available in memory. The availability makes people dramatically overestimate the probability of being attacked. The overestimation generates public concern. The concern generates more coverage. After a single high-profile shark attack, beach tourism in the affected region can decline 20-30% — a multi-million dollar economic response to a risk that is statistically less dangerous than the drive to the beach.
Crypto hype cycles run on the same mechanism. In 2021, stories of ordinary people becoming millionaires through cryptocurrency investments saturated social media and mainstream news. Each success story made crypto wealth more available in memory. The availability made people overestimate the probability of similar returns. The overestimation attracted new investors. The new investment pushed prices higher. The higher prices generated more success stories. Bitcoin went from $10,000 to $69,000 in 18 months. The cascade wasn't driven by fundamentals. It was driven by the self-reinforcing loop between stories, availability, and behaviour. When the stories reversed — losses, bankruptcies, fraud — the cascade reversed too. The same mechanism that inflated the bubble deflated it.
The "Great Resignation" narrative followed the pattern. In 2021, media outlets reported a wave of workers quitting their jobs. The framing — millions abandoning traditional employment — generated enormous coverage. The coverage made quitting seem common. The perceived commonality gave people social permission to quit. Some quit. Their quitting generated more data points for the narrative. The narrative generated more coverage. Economists later showed that quit rates, while elevated, were consistent with a tight labour market and pandemic recovery — not a structural transformation of the employment relationship. The gap between the narrative ("everyone is quitting") and the reality ("quit rates increased modestly in a hot labour market") was the availability cascade in action.
Kuran and Sunstein's insight was that availability cascades are not just cognitive errors. They have political and regulatory consequences. Public fear of a risk, inflated by an availability cascade, generates demand for regulation. Politicians respond to the fear because ignoring it is politically costly. The regulation addresses the perceived risk rather than the actual risk. Resources flow to low-probability, high-availability threats and away from high-probability, low-availability threats. The result: society over-invests in defending against shark attacks and under-invests in preventing falls.
The cascade has a structural companion: preference falsification. People who privately doubt the prevailing narrative stay silent because expressing doubt carries social costs. The crypto skeptic at a 2021 dinner party learned to nod rather than argue. The manager who doubted the "Great Resignation" framing kept quiet because the narrative had acquired moral weight — questioning it felt like dismissing worker suffering. The silence of skeptics removes the corrective force that might slow the cascade. Without pushback, the narrative accelerates. Without acceleration, there would be pushback. The cascade sustains itself by suppressing the very mechanism — public dissent — that could deflate it.
