Laugh track

I was at a luncheon the other day having a lovely time chatting and laughing when suddenly I heard myself laugh. It was like slow motion hearing, is that possible? My laugh had changed. Out of the blue I had a different laugh. I didn't try to have a different laugh, I had actually never thought about how I laugh. But suddenly it's different. How does that happen? For the next week I strained to hear myself every time I laughed. Always the new version. What decision was made and by what part of me to make a new sound when I'm happy or amused? I am baffled.