Does My Son Have A Twitch?

Every once in a while when I walk in the room Z will put his head to his shoulder and look at me funny. At first I thought he had an earache, then I started to panic thinking that he had some sort of neurological disorder. Well now I don't believe it is either of these reasons that cause Z to act so strangely. We were outside today and I told Z that we were going to have to go in for his nap. I asked him which books he would like to read and then he did the shoulder thing and laughed. It was then that I realized that I sometimes cock my head when I ask him questions and he is mimicking me!!! So to test this theory, I cocked my head again and he did it right back. I burst out laughing as did he and I then realized that S and I need to modify a bunch of behaviors because before long he will be copying everything we do!!!