It's been a while but there definitely are studies. For most "knowledge workers" the biggest jump in productivity was going from one to two; for programmers ha

It's been a while but there definitely are studies. For most "knowledge workers" the biggest jump in productivity was going from one to two; for programmers having three was a non-trivial productivity boost. All of that said, there are times I unplug the laptop from the dock so I can have just one app -- full screen -- in order to concentrate without distractions. Depends on the task but in general two monitors is the sweet spot.