However, if you observe, the smile of a baby actually contains a variety of meanings. Her smile is not just the sign that she was glad to see mother or father, but also more than just communicating meaning. Smiling babies also showed a brain development.
From birth, infants are able to show his grin, but smile is often just a quick and spontaneous nature. Grin was triggered by the inflammatory neurons in the brain stem, but not influenced by a good mood. There are times when your baby is asleep, a smile will come out by itself. Some scientists estimate the smile is caused by motor cells near the brain where the REM (rapid eye movement, in which the brain to process data and memory so that the baby often dreaming or delirious) originated.
Communication between parents and children do not only occur in one direction, when a parent caring for a baby, but also when there is a two-way interaction. That's what happens when the child began to show a genuine smile. There was a attachment (bonding) between you and your baby.
However, psychologists also predicted, the babies are bigger still often show his false smile on the parents. Foreigners, especially, just goto this fake smile. So if you're teasing your friend's baby, and she smiled, not ge-er first. Maybe he was just making small talk at you.
Source : ozzyatyogya.wordpress.com/