A Change in Noelle 20 months

The other night a friend came over for dinner. Ryo made a wonderful dinner of porkchops and gravy, salad and crunchy fried potatoes. We also had cake with vanilla ice cream. Oh that was just delicous! But I am not writing to tell you about our dinner or the fact that my friend came over but something else. Something about social blunders. Taboos.
Noelle is 20 months old now. We were all eating dinner and talking and Noelle was having fun and enjoying the change of pace (having a guest for dinner) when it happened. Noelle was getting excited and she accidentally lost the piece of porkchop that she had in her mouth. It came flying out and landed on the saucer of porkchops. She was surprised but my friend was even more surprised. He seemed a little bit disgusted. Perhaps that is too strong of a word but he did not think it was cool to have her half chewed food back out on the table. He has shown through his actions before that he really likes his food clean. Through raising Noelle we have lowered our standards a little as to what is clean enough food to eat since she often dumped her plate into our laps or on the floor. Anyways, his reaction to her losing her food onto the table was strong. What happened next is the interesting part. Noelle, upon seeing his reaction, got a cloud on her face. She wrinkled her eyebrows together and looked down. Her mouth was half opened and her lip began to quiver. We could see that she was trying to hold back tears. She was trying not to cry. She didn't know what to do or how to react to his reaction. She realized that she did something that was not acceptable. All three of us had to work to assure her that it was alright. Or friend did his best to get her smiling and giggling again. What we saw was that she realized, for the first time, that some things are not acceptable in "society". I amlost certain she wouldn't have reacted that way if the person reacting strongly to her behaviour was one of her close family. But I could be wrong. Another possibility is that she is starting to learn to control her emotions. Her trying not to cry, instead of just bawling out like normal, shows her trying to control, trying to deal with her emotions. Her having those feelings shows her developing socially. Of course, I really have no idea what I'm talking about but it was obvious to Ryo and I that she was showing a new area of development that we had not seen before.