I can imagine there being a small (absolute) productivity boost due to psychology for some people. Given fewer hours to do the same amount of work, I can see a

I can imagine there being a small (absolute) productivity boost due to psychology for some people. Given fewer hours to do the same amount of work, I can see a lot of people feeling slightly more pressure, and because of this, entering into more states of productive and efficient work. On the other hand, given more hours to do the same amount of work, many people will procrastinate more often, which makes it harder to enter those more efficient states of "deep work". This could lead to a lower amount productivity per hour, and depending on the magnitude of this difference, this could somewhat paradoxically add up to a smaller amount of actual work done. Another thing which could contribute to increased productivity per hour is more sleep and less stress gained by working fewer hours, especially when compounded over time.