What To Know About When Babies Start Smiling

By about 6 to 12 weeks, your baby will begin to smile in response to you (social or "real" smiles). Until then, sweet-looking grins are automatic reflexive smiles in response to gas and other bodily functions.

You can tell the difference between a reflex and real smile by the timing and duration. Generally, reflex smiles tend to be shorter and occur randomly, when the baby is sleeping or tired. Real smiles, on the other hand, occur in response to something, like seeing a parent's face or hearing a sibling's high-pitched voice, and they are consistent, Dr. Gettleman explains. When it's the real deal, you will see the emotion expressed in your baby's eyes.

At first, your little one's happy face will be in response to a mix of

 vocal and visual stimulation. They may light up from watching you sing a favorite lullaby or talk through a particularly yucky diaper change. Later, when their vision improves, simply seeing the face of their favorite people will be enough to make them crack a smile. You'll be the recipient of most of your baby's smiles, but they'll also exchange grins with others (that is, until stranger anxiety kicks in at around 6 months).

Smiling and Your Baby’s Development

When babies smile, it’s a sign that their vision has improved and they are able to recognize faces. Their brains and nervous systems have matured enough to eliminate reflex smiles, and they are now aware that smiling lets them connect with others.