> Iirc, there are several of studies that imply that if you have the same developer working 40 vs 32 hours, the difference in output is often negligible, since not all hours worked are the same in terms of effectiveness.
I guess it depends on the work. In my example, hanging siding on a house, the non-productive work is quite minimal. I guess that can vary depending on the work one is doing. The non-productive work still needs to get done so the productive work can get done, though.
> Would you produce twice as much if you were to work 80 hours? Probably not, right? You'd maybe produce about 1.5 times as much, and the quality of your work would suffer greatly, leading to more work in the future.
I doubt many people can sustain their work output over 16 hours for most jobs. But that's not really what we're talking about here.
> The same effect might work in the other direction, up to a certain point.
Sure, if you work faster when you work less hours. Are you saying this is what happens? Are you seeing people get too fatigued after 6 hours of work so that their productivity is diminished? I've not seen that in general with the people I've worked with or the work I do over the years.
> The 40 hour work week is not god-given, in fact it has been reduced quite a number of times in the past (mostly due to unions, like most working condition improvemens). So I can not understand why so many people act as if it were set in stone.
I'm not sure where this came from because I don't think any of those things. I think that the only way for work to get done is to do it. However many hours per week that takes is fine. I don't understand the argument that working less doesn't mean you get less work done in general.
All that said, I realize there might be something different to brain fatigue vs body fatigue when doing brain work (software development) vs physical work (construction). I've largely done physical work and can't relate well to brain work except as a hobby and occasional small bits of work.