Yes, but the study seemed fairly focused on single task performance. I don't think I can do a single task for even 40h/wk (maybe 20-30, tops), but running a startup or being dev/devops at a fast growing startup involves a lot of varied tasks. Performance on these doesn't really draw from the same pool.
But again the results this article cites point in the opposite direction:
"... research shows that knowledge workers actually have fewer good hours in a day than manual laborers do — on average, about six hours, as opposed to eight."
"Knowledge worker" in a study cited from Alternet is probably "programmer at a large soul-sucking corporation." Startup founder is fundamentally different.
Motivation to build what you really want to build is completely different from being motivated to work for a salary to avoid starvation and keep your family going.
Motivation, and particularly knowing exactly how the work you will do will benefit (yourself, your friends, your company, the industry, society).
I imagine it's a lot easier being a doctor who is actually helping individual people squeeze in one more patient, vs. spend overtime filling in paperwork. Same difference between working on an awesome product where you have total visibility into the whole process, vs. beng a cog in a much larger wheel.
