Hi OP: forgive me, I skimmed really quickly through the responses and hope I'm not repeating anything.
I have an extremely personable and extroverted DD, and I've seen similar reactions from other kids (kid won't acknowledge her; kid moves away from her; kid looks scared). DD is almost six and she's been rather forward with people for as long as I can remember. In a way, it drives me nuts, because I realize that I may have failed in some respect to teach her boundaries. DH and I are talkers, and except in limited situations, we normally chat away. The difference for us, though, is we know when to stop and we have probably developed detectors which allow us to understand when to withdraw or when communication is unwanted.
I'm not a child psychologist or any kind of expert on growth, but I think that a lot of kids in the 3 - 7 year-old range are still learning communication skills and what is appropriate when and where. Then there are just kids who are introverted or disinterested. I run into adults like that every day but I've learned not to take it personally. But, I think it's hard to get to the point where you don't take things personally. It took me many years.
One thing that has worked for me is when I see that a child is not going to be responsive, I engage in some sort of distraction to divert DD's attention from the other child. I also have to talk to her a lot about boundaries. She is beginning to grasp that personal space is important to others. It's been a hard thing to do because she just automatically assumes that everyone is all peace and love and rainbows and laughter. Recently, one kid at her summer camp called her "annoying." Put in his shoes, I can't say that I totally disagree with that assessment. I know that sounds harsh but at some point one has to understand how others feel and perhaps modify one's behavior accordingly. The "annoying" situation actually gave me a good in-road in discussing the issue with DD. She's at a point now where we can have these kinds of conversations and it is actually sinking in.
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