DIFFERENT PERSONALITIES!

Those of you with more than one child, at what point did you notice that your children have different personalities? I think I realized early on, but it is becoming more and more noticeable these days. What I have noticed recently is that Andrew plays so well by himself. In fact, he loves playing by himself. Joshua always wanted someone to play with. I mean he had our full attention and ate it up, but not sure if that is why he always wanted and still does want someone to play with. Andrew, does not get our 100% attention. Our time is split between he and Joshua. So, is that a learned trait, or would he have been that way anyway?
Andrew has also learned a lot from his brother. He already knows how to play with the kitchen, throw and roll a ball, make a car go, and get into things he should not. It is a new world with two...mankind is amazing!