ShallowGal once read this study where researchers had a bowl of goldfish crackers and a bowl of broccoli. They made yummy faces for the broccoli and yucky faces at the crackers. Then they would put out their hand and say "Can I have some?"
14 month olds would give the researcher the goldfish crackers, but at 18 months they would hand over the broccoli. The assumption was that the children began to realize that different people like different things ~ the beginnings of empathy development.
Empathy, Schmpathy. ShallowGal thinks that the older babies were trying to keep all the goldfish crackers for themselves.