Answer :
Answer:
Social smile
Explanation:
Newborns occasionally smile while they are sleeping. However, between the sixth and eight week of life (2 months old), babies develop a smile in response to someone else's smile, this type of smile is called "social smile" and is a reciprocal smile that invites people to interact with them.
Before that, the is no really social coordination between a baby and another person. However, the advent of social smile means that the baby's brain is developing and that he/she can get attention by smiling.
This is the true moment where parent and infant exchange looks and facial expressions.