Thinking about it a bit, I realized that recognizing shapes out of context is an skill that would help kids learn to read. So I'm guessing that for those of us who have really early readers we saw our kids do similar things at not quite 2. One part of learning to read is learning recognize a particular shape (the letters) even when you see it out of context. And if the kid thinks picking out countries on a map is fun and has a good memory for this type of thing, all it takes is playing this game multiple times.

Fairly sure this thread has gone a bit off topic as I don't think it has much to do with autism, but I'm finding it interesting.