I FORGOT I also wanted to add that those two things are separate for the purpose of this discussion: - How people feel (after shorter or longer work periods)

I FORGOT I also wanted to add that those two things are separate for the purpose of this discussion: - How people feel (after shorter or longer work periods) - How productive people are. From my experience, while doing a more mundane "conveyor belt" type of job I sure would like to have shorter work days too, I'm still able to churn out pretty much consistent quality to the end. That is different from (very design oriented, vs. standard not-much-brain-needed) code writing, where quality of what I produce suffers dramatically and I have to redo everything the next day(s) or get a lot of hard to maintain and/or debug code. Of course, people may burn out more quickly or have negative health outcomes later, but that still is a different discussion than the one about productivity.