1991年，诺贝尔经济学奖得主保罗·克鲁格曼（也许是当今世界最具威望的凯恩斯主义者）告诉人们预期能否自我实现取决于基本的经济条件。
In 1991, the Nobel laureate economist Paul Krugman, who is perhaps the world’s leading Keynesian today, showed that whether or not expectations are self-fulfilling depends on underlying economic conditions.