Human productivity, the demand for skill, and working less....

I'm a huge proponent of "working less".  My experience working part time loading trucks at UPS has sold me on the idea that people work too much.

In fact I'm always telling my wife she and her coworkers should unionize and impose 35 hour work weeks--as I selfishly want her less stressed and better paid.

But I caught this factiod in this post 15 Tips for Taming Distractions When Trying to Create | World of Psychology

People tend to be productive for 4.5 hours a day, 

I want to know more.  I assume she didn't just make up that factoid out of thin air.  If anyone knows any research on human productivity shoot it my way as i'm intrigued by the potential to increase productivity by working people fewer hours.

The other day Mark Thoma was worried about the possibility that the demand for skill is falling. I realize his concern was for other reasons but I want to ponder a "so what" to such a state of affairs. In highly industrialized economies there is no reason why we can't be a nation of philosophy and economics majors who work at McDonalds and UPS part time (spending the rest of the time raising families, politically engaged, traveling, writing, sleeping).  There is no inherent reason (aside from low pay which has more to do with how organized these sectors are) this would be a bad thing.

As Dean Baker always notes, there is no such thing as a "bad job".  Scrubbing toilets can be a great job--it depends on the pay and benefits not the job task it self.

So if human productivity tends to decline after 5 hours and the demand for skill is declinging--we should be pushing for 35....no, better, 30 hour work weeks.

We have mass unemployment--so its not like we don't have workers to tap in to to fill those vacated hours demanded.  Increase productivity and decrease unemployment--oh and improve the quality of life of people as they have more time to do pleasurable activities.