Conventional wisdom, and many studies, hold that 40 hours of work per week are the optimum before exhaustion starts dragging your productivity down too much to be worth it. I read elsewhere that the optimum is even lower for creative work, namely 35 hours per week, though the sources I found don't all seem to agree.
In contrast, many tech companies in silicon valley demand (or 'encourage', which is the same thing in practice) much higher work times. 70 or 80 hours per week are sometimes treated as normal.
How can this be?
Are these companies simply wrong and are actually hurting themselves by overextending their human resources? Or does the 40-hour week have exceptions?
How high is the variance in how much time people can work? If only outliers are hired by such companies, that would explain the discrepancy. Another possibility is that this 40 hour limit simply does not apply if you are really into your work and 'in the flow'. However, as far as I understand it, the problem is a question of concentration, not motivation, so that doesn't make sense.
There are many articles on the internet arguing for both sides, but I find it hard to find ones that actually address these questions instead of just parroting the same generalized responses every time: Proponents of the 40 hour week cite studies that do not consider special cases, only averages (at least as far as I could find). Proponents of the 80 hour week claim that low work weeks are only for wage slaves without motivation, which reeks of bias and completely ignores that one's own subjective estimate of one's performance is not necessarily representative of one's actual performance.
Do you know of any studies that address these issues?
Right, I'm saying that I do think it's possible that people working 60hr weeks might be more productive while being unhappier than the 40hr people. I don't trust that happiness and productivity are tightly correlated enough that an employer trying to get more of the latter out of me will help me out with the former.
Plus, there are a bunch of jobs that currently exist where the model is to extract a lot of productivity over 2-3 years while quashing an outside life and then to just hire a new crop of people when your current set burn out (TFA, I-banking, Hill jobs, etc).
I agree with all that. The only thing that puzzles me is that it looks as if you expect me not to, and I'm not sure how I gave that impression.
Perhaps I should make it explicit that my comment four upthread from this one wasn't in any way trying to suggest that employers can be relied on to do what's best for their employees, or to criticize you for your choice of jobs, or anything like that. I got the impression that you were suggesting that the question of what working hours lead to max productivity is a duly one or a boring one or an improper one, which I don't think it is even though employees should be thinking about other things besides productivity-maximization.