I've been thinking a lot about overwork recently (see my new cover story, "The Real Reasons Why You are Working So Hard"). The U.S. has grown much faster than Europe, and at the same time a lot of people in the U.S. has been working longer and longer hours, while Europe has been working shorter hours.
Hours and growth may be connected. In my cover story, I talk about how globalization and information technology may be causing people to work longer hours, since they cannot give up their old tasks.
But the causality may go the other direction as well. It may be that information technology only has a productivity-enhancing effect if you are prepared to put in a lot of extra hours learning how to put it to good use. You are doing your old job, and learning about the new stuff at the same time. Extra time and extra payoff.
For example, imagine a journalist (much like me), attached to a print magazine. The magazine has to come out, week after week, and those demands don't stop.
At the same time, though, this journalist has to spend time getting up to speed on blogging, online collaborations, and so forth. More hours...but that's the only way to success.
If you have a culture where those long hours are not acceptable, then the learning process takes much longer.