Your baby's flinch when his sister screams feels alarming, and you want a clear answer about whether it harms him. A startled reaction is usually a normal reflex, not a sign of lasting damage, but ...

Since the day a baby is born, his or her body is pre-programmed with survival reflexes. One of these is the Moro reflex or the startle reflex, one of the numerous primitive reflexes of a newborn baby ...