Think of any habit. Brushing your teeth. Every night at 8:00 you brush your teeth. So, down the road, you just do it automatically, the tooth brushing person takes over and 7:58, marches you to the bathroom, you don't even think about it, notice it, nothing.

Lots of people arrive at a destination and don't know how they got there, they were dissociating. The more one "practices" that, allows that, the more often it's going to occur. Get in car, start to work, you're "somewhere else". Happens when you're reading a book and get into the story and don't pay attention to what's going on around you; my mother use to have to call me 3-4 times if I was reading. I'm sure you've seen the TV commercial for some insurance company and how much they "care" which starts with the woman yanking the pizza delivery guy back when he steps off the curb into oncoming traffic. He wasn't paying attention.

We have to focus our minds but that takes practice and experience. A child doesn't have much of either of those. If something really bad happens, a child is going to dissociate. If it "works" well, feels like another person (ego state) came out and took the beating so the child could continue under horrible stress/circumstances, the child's mind is likely to create other such people for other situations. But, let's say we have a 5 year old girl child who was abused and came up with a 12 year old tough boy state; the 5 year old girl is still there but may not get to "mature". So, she may later, when the person is an adult, "come out" at the pet store because as a "real" 5 year old she loved kittens and wanted a kitten.

If you go to therapy and really horrible memories come up, proably whoever was around "then" when the memory originally happened is going to come out again since it worked so well the first time. So, I can see 10 and 12 year olds driving.

Doesn't matter a whole lot (to me, may to you! :-) if they are ego states that have split off or alters. They're the extreme end since most people "come out of" ego states eventually, don't just switch. But the element of habit gets in there. The more ego states/alters one has and more often they're needed/used, that's like brushing one's teeth at 8:00 every night; it gets "automatic" and that's where having alters gets really really difficult and feels like one has no control and like "they" are doing something. As Pogo, a 1920's-40's comic character said, "We have met the enemy and he is us".

http://www.igopogo.com/we_have_met.htm