If we are playing with our daughter she smiles and laughes and interacts very well but when we went to her 18month check up there was a question asking When you smile at your child, does he or she smile back at you? If we are just sitting there doing nothing and I out of nowhere smile at her she doesn't smile back at just me smiling but if we are playing hide and seek or peek a boo or other interactive games she smiles but she will never just smile back at me if it's just her sitting there and I smile at her out of nowhere. Is this normal behavior?