This is a very interesting article:
CONSIDER WHAT IT MIGHT FEEL like to be a baby in a world of relentless and unpredictable sensation. An overwhelmed infant might, not surprisingly, attempt to escape. Kamila compares it to being sleepless, jetlagged, and hung over, all at once. “If you don’t sleep for a night or two, everything hurts. The lights hurt. The noises hurt. You withdraw,” she says.
Unlike adults, however, babies can’t flee. All they can do is cry and rock, and, later, try to avoid touch, eye contact, and other powerful experiences. Autistic children might revel in patterns and predictability just to make sense of the chaos.
At the same time, if infants withdraw to try to cope, they will miss what’s known as a “sensitive period”—a developmental phase when the brain is particularly responsive to, and rapidly assimilates, certain kinds of external stimulation. That can cause lifelong problems.