Scientists found that certain mice kept in cages were susceptible to picking and self destructive behavior of that sort. If that same type of mouse was given a stimulating environment while young, then he would grow up to not pick at himself. Importantly, he would not pick at himself even if he was put back into a boring cage as an adult.
I have noticed that there have been a lot of "no picking" reports on this list. It could be that this is yet another result of our early intervention. Now, maybe some children are more vulnerable to picking and they would do it no matter what the early intervention. But, what we may be seeing is that we are able to rescue the majority of teh children from this symptom by providing them a rich environment with a great deal of stimulation.