I have a little one in my care who is just over 22 months old and has suddenly started hitting, pushing, pulling hair, kicking, etc. She seemingy does it for fun/attention as she doesn't do it out of anger or retaliation...she is quite calculated about it and just walks across the room and starts hitting another child with a plastic hammer for example. When I tell her to stop, she usually does and mimics teh behaviour she is supposed to do "nice nice" and pets the child on the head nicely, but then she is right back at it a few minutes later. She seems completely unperturbed by time-outs, removing toys, even time-outs in another room as I tried today. Using a sharp, serious tone gets no response, talking to her about how we play nicely does not work either. I am watching her as much as possible to try to prevent it from happening, but every time I turn away, she does it again. Even in the car, she is kicking the child beside her. Is this normal? I have never seen such calm aggression before...no anger, no emotions, just hurting others to see what will happen. Any suggestions?