US vs Europe: hours in lab

[Linda Kingsbury]

In article <9601198247.AA824750380 at nas.edu>, jjoy at nas.edu ("Janet Joy") wrote:

>     It seems that American students have little choice but to work to
>   extremes since they are compared to each other in the job market.   I
>   wish I could believe that the American worker bees learned so much more
>   and were so much more productive than their counterparts in other
>   countries, but my experiences don't really support that idea. . . .
>   although I admit anecdotal data should be taken with a grain of salt.
>   Maybe my experiences are atypical.   My suspicion is that Americans are
>   just busier, but neither more creative, wise, or good at science than
>   scientists in other countries.

An interesting question...do longer hours make a person more productive? 
Up to a point they may.  On the other hand, overwork is well known to
decrease creativity, accuracy, etc.  Are Americans overworked, or
Europeans underworked?  What is the ideal number of hours/week for best
productivity?  What, if any, extenuating circumstances should be
addressed?  Commute time?  Family?