当人不知道方向的时候一般会跟着大多数的群体。在人的祖先群居的时候，一个一意孤行独来独往的容易和群体失去联系。在古时候一个人生存的概率比群体要小得多。

Herd behavior describes how individuals in a group can act together without planned direction. The term pertains to the behavior of animals in herds, flocks and schools, and to human conduct during activities such as stock market bubbles and crashes, street demonstrations, sporting events, religious gatherings, episodes of mob violence and even everyday decision making, judgment and opinion forming.