I'm a proponent of this theory, and it worked for me in Law School. I would only study for two two hour sessions each day, after which I was free to do whatever I wanted. This worked quite well for me, and I always felt fresh and sharp, especially when finals came around.
I also did the same study plan for the bar exam and feel like it worked well there too, i.e. passed it on the first try with a minimum of drama, the whole thing was actually quite pleasant.
In contrast, many of my peers would study basically around the clock, pull all nighters, made their lives miserable and didn't do any better, and more often than not quite worse.
I tend to agree, although I think you can concentrate longer for short, unsustainable durations. My standard schedule in law school was a few hours during the semester, then a few weeks of 8-10 hour days around finals.
My take away from the experience was that 8 hours of real work is really a lot of work. And distractions are absolute poison: internet, cell phone, etc. Nothing quite like locking yourself in a room with just a book and highlighter--no computer, no cell phone, no people. You add those things to the mix and it can easily take a 16 hour day to get 8 hours of real work done.
I also did the same study plan for the bar exam and feel like it worked well there too, i.e. passed it on the first try with a minimum of drama, the whole thing was actually quite pleasant.
In contrast, many of my peers would study basically around the clock, pull all nighters, made their lives miserable and didn't do any better, and more often than not quite worse.