Around 2 months of age, your baby will have a "social" smile. That is a smile made with purpose as a way to engage others. Around this same time to about 4 months of age, babies develop an attachment to their caregivers.

Can babies smile at 4 weeks old?

It may be possible for your baby to smile at 4 weeks but usually only while he's sleeping. This is called a reflex smile. Your little one may not flash a true smile until about 6 weeks or a little older, and these true smiles happen when he's awake and alert.

What is the earliest a baby can smile?

Typically, babies start smiling between 6 and 12 weeks, but you may notice a smile or smirk soon after baby's born. These early smiles are called “reflex smiles.” Babies start reflex smiling before birth and continue to do so as newborns.