I think silicon valley is an atypical example compared to the typical workforce. We are presumably talking about the high end of the technological productivity spectrum. And as we know the tails come apart. I'd guess that a lot of special people cluster in these jobs. Sure the tech companies try a lot to make work convenient - but I think a lot of the people working there are at least partly such highly productive because they invested lots of time into technology all their life. Working long ours in your calling is normal.
Look at me: I work 40 'normal' free-lance hours - more is not sustainable with 4 children. But many days I sit behind my PC 4 to 6 extra hours (often in thenight because I need less sleep). These are productive hours mostly. Coding, researching, learning, LW. Also on weekends. If a topic interests me I can keep up flow and concentration 16 hours straight. It is just for my family streak that I don't work insane business hours.
And I guess there are other people our there that are alike. Thus normal workplace lessons don't apply here.
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?