why do babies laugh
Neonatal smiling occurs from birth to one month of age and shows no emotional content. Smiles are spontaneous and often occur while the baby is drowsy or during REM stages of sleep. Baby smiles are subcortical in origin and will actually decrease with maturity (so premature babies smile more than full-term babies). And, contrary to popular belief, baby smiles have nothing to do with gas. 1  1.