Years and years ago, I worked as a blackjack dealer. We had 20 minute breaks every hour. It seemed ludicrous to me at first, but the job has essentially two main components - solving a lot of very simple math problems quickly and without errors, and customer service. By keeping all of the dealers fresh, the casino was able to ensure that problems were minimized. Adding cards up to 21 isn't exactly mental gymnastics, but do that at a rate of up to 280 times in an hour and it's actually kind of surprising that more mistakes aren't made.
I've often wondered about how that kind of schedule would play in software development. I find that my own code is better when well rested, but even after all these years I've never been able to force myself to take breaks that frequently.
The side effect of frequent and scheduled breaks was social interaction that was usually work-focused.