A substitute teacher was trying to make use of her psychology background. She began her class by saying, "Everyone who thinks you're stupid, please stand up." Right away, Little Johnny stood up. The teacher said, "Why do you think you're stupid, Little Johnny?" "I don’t, ma'am, but I hate to see you standing there all by yourself!"代课教师试图运用她的心理学知识。开始上课时，她说：“谁觉得自己很愚蠢，请站起来。”小约翰马上站起来了。老师问：“为什么你觉得你很愚蠢呢，小约翰？”“我不觉得我很蠢，只是我不愿意你一个人站在那！”