I'm surprised that no one has mentioned college and education in the context of signaling: http://en.wikipedia.org/wiki/Signalling_(economics)

A degree from a Tier-1 school and high GPA is a signal to potential employers that you are a hard worker and smart. This appears to hold well for "easy" majors who don't really use anything learned in college at work (except thinking and writing creatively) and less so for "hard" majors who do actually need to know stuff about biology, math, whatever to do well.