Herd behavior is the tendency to follow and mimic what a larger group is doing, rather than relying on independent analysis — and it's one of the most consequential biases in financial history, because it doesn't just distort individual decisions, it amplifies collective ones. The psychological pull is real and understandable: being wrong alongside a large group can feel less personally risky or embarrassing than being wrong alone, even though the actual financial outcome — the money gained or lost — is identical either way. That social comfort in shared error is exactly what makes herding so persistent, even among people who intellectually understand the risk.
This platform's own case study library documents the mechanism repeatedly, in both directions. During a bubble, herding draws in more participants purely because prices are rising and others are buying — disconnected from independent analysis of underlying value — which is a core piece of what happened during the dot-com era and, centuries earlier, during the Dutch Tulip Mania. During a panic, the same mechanism runs in reverse: people sell partly because others are selling, amplifying a decline beyond what new information alone would justify.
Correct moves you up, wrong moves you down — reach 100 to master this lesson.