Researchers at Philadelphia's Temple University claim to have conclusively proven that tough love advocates are right, and the best way to get a reluctant baby to sleep is to let it scream like Janet Leigh until it passes out.
The study just published in Developmental Psychology gathered data on the sleep habits of more than 1,200 babies, checking with new parents at six, 12, 24 and 36 months. It found that two-thirds of kids slept through the night by six months, or woke up long enough to need attention only once or twice a week. The remaining third of the kids woke up and fussed, nightly.
Two out of three kids sleeping all night at six months? The findings recall the old stats joke: that researchers had discovered two out of three men masturbated regularly, and that one out of three was a compulsive liar. But the parental reports, and the infant sleep numbers are solid, say the researchers.
We identified 2 distinct developmental patterns. One group, labeled Sleepers, included 66% of the children. These children showed a flat trajectory of sleep awakenings from 6 through 36 months, with mothers reporting their infant awakening from sleep about 1 night per week. The second group, labeled Transitional Sleepers, included 34% of the infants. These children had 7 reported nights of awakenings per week at 6 months, dropping to 2 nights per week at 15 months and to 1 night per week by 24 months. Compared with Sleepers, Transitional Sleepers were more likely to be boys, score higher on the 6-month difficult temperament assessment, be breastfed at 6 and 15 months old, and have more depressed mothers at 6 months old.
The study's authors claimed that babies who often fell asleep while being rocked or breast feeding, and received the quickest parental attention when they cried at night, tended to sleep less and more fitfully, for more months.
The study is one of the more extensive efforts to resolve a long-standing debate between advocates of so-called "Cry It Out" methods of putting li'l Amber or Carlos to bed, and advocates of "No Cry" strategies, that usually involve greater contact and rapid soothing.
One question: the mothers of the waking kids are more likely to be depressed because they aren't getting any sleep, right? An abstract of the research did not mention fathers.