一位科学家做过这样一个实验:把许多跳蚤放到一个广口瓶里,瓶口用透明玻璃盖住。刚开始时,跳蚤们拼命地往外跳,但都被玻璃碰了下来。一段时间以后,即使把玻璃取下来,那些跳蚤也只能跳瓶子那么高。这些昔日的跳高冠军,被封闭在了自己界定的高度上。 One scientist had an experiment in which many fleas were placed in a jar with a clear glass lid. At the beginning, the fleas desperately hopped out, but they were all touched by the glass. After some time, even if the glass removed, those fleas can only jump bottle so high. These former high jump champion, was closed at the height of their definition.