Herd Mentality
Individuals tend to follow and replicate the behavior of the majority, overriding independent judgment.
Origin & History
The concept has roots in 19th-century crowd psychology, notably Gustave Le Bon's 1895 book The Crowd. Psychologist Solomon Asch formalized a key mechanism in 1955, showing that people will publicly agree with an obviously wrong answer if the group around them chooses it. The specific term 'herd mentality' became widely used in financial analysis in the 1980s to describe investor behavior in bubble markets — where individual analysis is replaced by watching what others are doing.
Real-World Examples
Investors who have researched a company and planned to hold it long-term sell during broad market panic — because everyone around them is selling. The social signal overrides the underlying analysis.
On an unfamiliar street, people reliably choose the busiest restaurant over an equally priced empty one — using crowd presence as a proxy for quality, regardless of whether it reflects actual experience.
Fashion cycles are driven by herd behavior: once enough visible people adopt a style, the critical mass creates social pressure to adopt it — until enough visible people abandon it, triggering the reverse.
Why It Matters
Herd Mentality evolved as a useful survival heuristic: if the herd is running, running with them is often safer than stopping to assess the situation. But in markets, elections, and complex decisions, crowd behavior is itself the variable being measured — making the herd signal self-referential and unreliable. The antidote is pre-commitment: write down your reasoning before exposure to group behavior, then compare your reaction to the reasoning afterward. If you diverged, ask why.
Related Laws
Can You Spot Herd Mentality in the Wild?
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The tendency for individuals to follow the behavior of the group, suppressing independent judgment — often driven by social pressure, uncertainty, or the assumption that the crowd must know something.
It creates bubbles (everyone buys because everyone's buying) and crashes (everyone sells because everyone's selling), often detached from the underlying value of assets.
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