Teddy Bear Effect
As the story goes, the computer science lab at Reed College has a rule that before you can ask for help with the programming problem you're working on, you have to first explain that problem out loud to the teddy bear in the corner.
More often than not, explaining your problem to the bear is enough to help you find the answer for yourself. Aside from reducing the number of questions to the TA's, this has some interesting benefits. Obviously the bear itself wasn't doing anything interesting, other than being a good listener. The very act of explaining your problem out loud, along with all your assumptions and thinking, allowed your brain to work on it in a different way, and provided a solution that you might not otherwise have found.
We've heard several different names for this phenomena but we generally refer to it as the Teddy Bear effect, to honour the bear at Reed College.
While often discussed in the context of software development, this scenario is hardly unique to the IT field. A 2007 study of four and five year old children demonstrated that their problem solving abilities were far better when they explained their thinking out loud to their mothers than they were when they worked quietly (even when their mother was still in the room).
If we accept that we have better problem solving abilities when we talk out loud even without having anyone respond, it isn’t a stretch to imagine how much better it would be if that person was working collaboratively with us to solve the problem. This is part of the magic of pair programming and mob programming.