Herding behavior

Herding behavior describes the tendency of individuals to mimic the actions of a larger group, often abandoning private judgment in favor of conformity. While related to information cascades, herding is broader: it includes irrational panic, cultural contagion, and the simple comfort of being wrong alongside everyone else. Information cascades are Bayesian; herding is often merely social.

The phenomenon has been documented in financial markets, consumer behavior, and political opinion formation. The classic example is the stock market bubble, where investors buy assets not because they have independent value but because others are buying. When the herd reverses, the crash is typically more violent than the ascent because the same social proof that fueled the boom now fuels the panic.

Herding behavior is not always pathological. In many domains—such as language acquisition or cultural transmission—herding is the mechanism by which stable conventions emerge from individual variation. The problem is not the behavior itself but the feedback topology that amplifies it without correction.