I had twin girls for a while. They were attached at the hip! It was really hard to get them involved with the other kids unless they were doing it together. And they used to hoard toys! They would make piles and hide their piles and no one was alloud to touch their piles... but cuter then anything! They didn't react emotionally to each other, if one got hurt the other would console her. If one didn't get her way and put up a face, the other didn't get too concerned, unless she was having trouble getting her way too.