Interesting stuff - and specifically, the numbers recommended are interesting. I've heard a 4-hour work day recommended in a few places.
Personally, I tried working 4 hours a day some years ago, whilst dealing with a death in the family. I was startled at how close to my usual 8+hour workday my productivity was - indeed, I'm not sure, looking at output alone, you could have told my 4-hour period apart from my usual work cycle.
I'll be interested to hear if anyone tries this 90-minute cycle specifically, and how it works out for them!
I think societal pressures would prevent a 4 hour workday even if it was more productive for many classes of worker.
A great many jobs are not fundamentally about productivity, for example a store checkout worker, a hotel receptionist and some IT operations work. In such cases the work is more about being available to cover certain hours and respond to various situations.
For such jobs it would become a hassle to swap workers around every 4 hours for no real benefit. Thus this sets a certain expectation for working hours.
If some types of workers were thus given significantly shorter hours within the same organisation there would be envy and shaming and accusations that those workers were not working as hard as anybody else.
A huge amount of those service jobs you listed, especially minimum wage, rely on specifically the 4 hour work day, or between 4 and 5. I just got out of food service and the 4-5 hour shift was especially common. Their reasoning is they're getting your best hours, so they cycle a lot of people working short shifts.
Working times/practices will vary across industries. So things like part time shifts, split shifts etc will seem normal to people working in food service in the same way that weird irregular hours might not seem strange to people working in startups.
I think though that once a particular industry has an expectation around certain working hours they will tend to try and apply that across the board in order to seem fair.
I worked in IT for a bank, for example which had a very strict 9-5 culture. Things like taking breaks for coffee/lunch etc were to very strict times and taking 30 seconds longer than allowed was a serious business.
I think they had these rules in place for the callcenter employees, where they needed to ensure adequate levels of availability throughout the day. In order to seem fair they made this a rule across all departments.
When I work on my own , if I have a hard problem I will sometimes prefer to go and walk for an hour rather than sit in front of the computer as this can help me think more clearly. However a bank employee would never be able to do this.
I worked for many years in blue collar service industries. The sort shifts have more to do with ensuring that the workers don't get full health benefits, thereby driving the cost of each worker down for the company.
You're right, Jiggy. For a lot of jobs, it's about coverage and service, being able to fill the hole and be familiar with the situation. Training new people to be effective is more difficult than it seems in any job; four or five hours makes it even more difficult.
Personally, I tried working 4 hours a day some years ago, whilst dealing with a death in the family. I was startled at how close to my usual 8+hour workday my productivity was - indeed, I'm not sure, looking at output alone, you could have told my 4-hour period apart from my usual work cycle.
I'll be interested to hear if anyone tries this 90-minute cycle specifically, and how it works out for them!