Caplan expõe seu argumento sobre educação e sinalização com detalhes aqui.
Um trecho interessante (não consigo formatar melhor por conta do bizarro “firewall” da faculdade):
3. On average, how much does schooling causally increase students’ marginal productivity by shaping their character, a la Eliza Doolittle or the Marines?
My answer: Relative to a carefree life of play, this accounts for another 20% of the gross marginal return to education. But relative to getting a job, the average character-shaping benefit of education is roughly zero. For very young children with negative marginal productivity on the job, I’ll admit the character-shaping effect is more positive. But by the time they’re teen-agers, the character-shaping effect is mildly negative relative to employment. As I told Bill Dickens:
Work inculcates the worker ethos; school inculcates the student ethos. The two are only moderately correlated. The most obvious differences: Work offers much more tangible rewards for good performance, and much harsher punishments for bad performance, than almost any school. School teaches students the wrong life lessons: Excellence doesn’t lead to money or status, and disruptiveness won’t get you fired.
Even worse, school often indirectly inculcates counter-productive character traits. Students spend a lot of their energy trying to show their fellow students that they’re defiant, cool, etc.