Who does not look furious to see the little smile, while his eyes staring at you with enthusiasm. "Mother coming home!" so maybe he cried. Tiredness after a whole day of work (plus tired of heart) was instantly disappeared, replaced by a sense of joy that overflowed unimaginable when seeing a smile on the face of the child.
However, when you observe, a baby smile actually contains a variety of meanings. His smile not only signifies that he is happy to meet his mother or father, but also more than just the meaning of communicating. The baby's smile also shows a development of his brain.