In the first six months, babies wake up for safety reasons and hunger. Tiny babies have tiny tummies, and they are indulged with this easy arousability. Their breathing mechanisms are maturing.
From six to twelve months, they wake up from teething pain. Separation anxiety also sets in. They begin to wake up in the middle of the night -- dark, quiet, lonely, behind bars -- and wonder, "Where's my momma?" And then they start crying.
From nine to twelve months, they are more aware that they are alone.
From one to two years, they start waking up for developmental reasons. This is when they start crawling and walking. Sometimes they'll wake up in their cribs in a kind of stupor and start crawling around. Sometimes they bang their heads from side to side and wake themselves up. They start practicing their locomotion skills.
From two to three, many kids experience nightmares, separation anxiety and fears. Scary dreams wake children up.
What advice would you give to sleep-deprived parents?
Nap when your child naps. Nap while baby is nursing. This is a wonderful way to catch up on some sleep. Try to share nighttime parenting. If mom is tired, then dad takes over. Wives should honor their husbands by giving them their share of nighttime parenting.
Have you noticed an increase in sleep problems among older children and adolescents?
Absolutely, and we can learn something from that. Sleep training -- the "let them cry it out" approach -- has been used for hundreds of years. My concern is that if night-waking problems are increasing, not decreasing, the sleep training must not be working. Maybe we have to change how we view infant sleep.