These differences have persisted in the most recent decade, even though tepid economic growth and labor displacement by smarter machines have weakened demand for high-skill, high-cognition occupations. Many college-educated workers simply have been forced down the occupational ladder into jobs traditionally performed by lower-skilled workers, who in turn have been pushed further down the occupational ladder or out of the labor force altogether.
即便缓慢增长的经济以及更智能机器的劳动替代作用也削弱了对高技能高分析能力职业的需求，但这些差距在最近十年依然存在。许多大学生直接被挤压到原本由低技能劳工承担的职业层次，而后者则被压到下一个层次甚至直接被排挤出劳动力市场。因此如果一个劳动者没有大学文凭，他的工资收入只会进一步下降得更低。