While reading this thread (or the title), my brother had pointed out that this could be true because they make you think about all the good things in the world, even in times where it's so difficult.
The article says that those who look at pictures of kittens frequently were able to concentrate at even a children's board game of Operation, and despite being slow, they consider their work delicate as the kittens they look. Even so, that's one other good look at how your mind on kittens work.