The Gambler's Fallacy

Believing past random outcomes change the odds of future independent ones.

  • informal

The gambler's fallacy is the belief that a run of independent random events makes the opposite outcome “due.” Because a fair coin has come up heads five times, it feels like tails must be more likely next — but each toss is independent and the probability never changes based on history.

Examples

  • “Red has hit six times in a row at roulette, so black is bound to come up now.”
  • “We've had three girls, so the next baby is almost certainly going to be a boy.”

Why it works & how to counter

Persuasive because we expect randomness to “balance out” in the short run. Counter it by remembering that independent events have no memory — prior results don't shift the next outcome's odds.