When our daughter was two and a half we had her in daycare at my wife's workplace. (Back in the day when they had that kind of thing). She was wearing pullup diapers at the time and of the slightly older girls said to her "You are a baby. You still wear pullups." Our daughter did not have a bowel movement for two days and then on the third asked to use the toilet. She was potty trained from that day on. It saved my wife and I a great deal of work and in it's own way something to be thankful for. However nothing ever struck me as how significant were members of group on getting someone to conform.
A recent article confirms with very young children the urge to conform even when the kids know that it would not be the optimal choice. Us adults are not much better as shown in this study. My sense in watching both sides of people's faces and feeling my postural adjustment to where I see the persona that I did not have a clue on how significant how my own use of myself conforms to what I see in others.