Xander wants to do everything Jessica does. For example, Jessica says "ow!" every time I comb her hair. Yesterday I was combing her hair, after dousing it with detangler spray. Xander came over and pointed at the detangler spray, which he frequently does. So I sprayed some on his head. Then he wanted me to brush his hair. So I did. Then, while I was brushing it, he started saying "Ow, ow!" Now, he's done this before, but I thought I was actually hurting him. He's got such little hair (compared to Jessica) and it's fine that I knew it wasn't tangled and that I wasn't hurting him. Then I realized he was saying "ow" because that's what Jessica does.
On a related note, he's developed this somewhat irritating habit of saying "owie" when he's upset. I think he realizes he gets more attention if he says that because we think he might be hurt. But it's reached the point of crying wolf. Now when he says ow, I don't believe that he's hurt, even if he is.