Why Babies Smile

Baby smiles at 1-2 months
At around one or two months, babies will gradually start to respond to environmental stimulation. Your baby’s first smile when she’s fully awake will likely appear between six and 10 weeks.
At this age, your baby’s brain is developing, her vision is improving and she can recognize your face. Your baby will likely respond to auditory stimuli first, such as music or mom or dad’s voice. Next comes a response to visual and auditory stimulation combined. The last thing to make baby smile is visual stimulation alone.