I'm curious if the 40-45 hour work week is cultural. Maybe if society was set up for a 20 or 60 hour work week, we'd see the same type of productivity cliff.
Before the 40-hour work week society was indeed set up for longer work weeks, and workers organized to reduce it. There's historical context for many countries given here: https://en.wikipedia.org/wiki/Eight-hour_day
And before industrialisation, working times, days, and years were fairly considerably less.
Employment is much more constant in some trades than in others. In the greater part of manufacturers, a journeyman may be pretty sure of employment almost every day in the year that he is able to work. A mason or bricklayer, on the contrary, can work neither in hard frost nor in foul weather, and his employment at all other times depends upon the occasional calls of his customers. He is liable, in consequence, to be frequently without any....
Some workmen, indeed, when they can earn in four days what will maintain them through the week, will be idle the other three. This, however, is by no means the case with the greater part. Workmen, on the contrary, when they are liberally paid by the piece, are very apt to overwork themselves, and to ruin their health and constitution in a few years. A carpenter in London, and in some other places, is not supposed to last in his utmost vigour above eight years. Something of the same kind happens in many other trades, in which the workmen are paid by the piece, as they generally are in manufactures, and even in country labour, wherever wages are higher than ordinary. Almost every class of artificers is subject to some peculiar infirmity occasioned by excessive application to their peculiar species of work.
I think it’s more like 60 to 80 hours per week of “work”, both personal and professional. A society set up for 60 hours a week would have you outsource pretty much all housework, shopping and assorted chores in order not to burn out. I believe it when people routinely do 70 hour weeks, but only if they don’t have a personal life of their own that they sink effort into.
> During the 40 hour week that work was outsourced to wives
It wasn't until the late 70s that married women start to maintain full time jobs in large numbers (The 'quiet revolution'), but the 40 hour week was in place 30 years earlier.
Of course now we have the situation where you have to have two full time earners to run a household. When I was at highschool in the 90s, I was quite unusual in having two working parents. My best friend for most of high school had a stay at home dad, who looked after him and his younger brother, my other close friend has a stay at home mom. That was fine, as house prices were still in the c. 4 time average income range.
It's the other way round now, where house prices are in the c. 8 times average income range, so it's rare to find anyone with a single income family, and UK society subsidises the two income lifestyle and childcare industry -- you get tax breaks for sending your 1 year old to nursery 50 hours a week, but not for asking a grandparent to look after them, or even reduce your hours so (god forbid) the parents can look after them.
In the Law, yes, the Fair Labor act was enacted during his presidency. But the Idea of 8 hours of work, 8 hours of sleep, 8 hours for what you will long predates him, and 8 hours was already a standard shift at some (many?) factories by that time.
Scandinavian and Slovenian immigrants to the USA, working as coal miners, felt that 8 hour days were important (http://collections.mnhs.org/MNHistoryMagazine/articles/52/v5... pg 254) and negotiated to have that included in their employment contracts.
So is it perhaps universal that 8 to 10 hours per day is what people feel comfortable with?