Those who hope their twenty-something offspring will eventually move out on their own probably shouldn't read Average Is Over, a new economic book by Tyler Cowen.

The general idea is this: the Great Recession exposed the painful truth that many middle-wage earners don't produce enough work to justify their salaries and benefits. And as the technological revolution continues to change the way we work, most won't be able to improve their skill set enough to qualify for high-earning jobs. High-wage jobs will require workers that can quickly and easily use computers to improve their production and profitability. Think about how computerized trading has changed Wall Street. Expect more of that.

Many mid-wage jobs will be replaced by computers, leaving Americans unwilling to improve their skills to either live off government benefits or work low-wage jobs. In our culture, we've been conditioned to expect mid-range salaries, especially after earning a bachelor's degree. Because of these cultural expectations, most are psychologically unwilling to accept a low-wage job instead.