Hesitation appears to be a fundamental brain feature that helps people and animals navigate an uncertain world and avoid costly mistakes. At the Winter Olympics, skiers, bobsledders, speedskaters, and many other athletes all have to master one critical moment: when to start. That split second is paramount during competition because when everyone is strong and skilled, a moment of hesitation can separate gold from silver. A competitor who hesitates too much will be left behind—but moving too early will get them disqualified.