Another word that gets thrown around a lot when people talk about sleep training is “attachment.” Attachment is an extremely misunderstood concept; basically, it describes a child’s relationship with his mother or father as it develops over the course of the first year of life. A child who is securely attached to his mother is confident that she is there for him, because she has been repeatedly and appropriately responsive to his cues and needs. A child who is not securely attached is not so sure mom can be counted on, because she has been unpredictable in her responsiveness or perhaps even abusive. Securely attached children go on to have stronger relationships throughout life and are more confidant, cooperative, caring and emotionally stable than those who aren’t securely attached to their caregivers. Attachment is powerful—no question—and important.
But attachment isn’t extremely fragile, nor is there a formula parents need to follow to ensure that it develops. “Don't get me wrong: I think nursing is great for lots of reasons, co-sleeping is fine, and carrying a baby in a sling is great, but you can do all of those things and not be a sensitive parent,” says Alan Sroufe, a professor emeritus at the University of Minnesota Institute of Child Development, who has studied attachment for decades. And no, you won’t threaten a secure attachment with your baby if you let her cry at night a few times, either: Sroufe let his own daughter cry it out for a few days when she was about 8 months old. (It worked.) ”Did I think she would be traumatized by this? No. This business of being sensitive and responsive—it's about being sensitive and responsive the vast majority of the time,” he says. (Sroufe believes, however, that crying-it-out is inappropriate for younger babies; some researchers have drawn a “safety” line at 6 months of age because that’s when infants develop object permanence, the ability to understand that mom and dad still exist when they’re not visible.)
But what if it takes weeks of intense crying, night after night, to sleep train your child? Here’s the thing: When crying-it-out is done properly, the experts say, it doesn’t take weeks. It takes days. In Middlemiss’ study, the babies stopped crying by the third night. A 1988 trial also reported significant improvements in infant sleep within three days using the method. Yet we’ve all heard horror stories about parents who have had to endure weeks upon weeks of all-night screamfests. I asked Marc Weissbluth, a pediatrician at Northwestern University and the author of the best-selling Healthy Sleep Habits, Happy Child, about the discrepancy, and he says that crying-it-out can take a long time, but typically only if the parents “have the child’s bedtime too late, or they’re not napping the child, or they’re doing intermittent reinforcement,”—i.e. they’re going back in to soothe the child instead of truly letting them cry it out. (Extremely overtired babies resist sleep training, and parents who soothe their babies during training reward the crying, giving them reason to do it again and again.) Fix these problems, Weissbluth says, and crying-it-out should work in three days.
It’s not just Weissbluth saying this. When the American Academy of Sleep Medicine reviewed the literature on infant and child sleep training, it reported that in 17 out of 19 published studies, unmodified extinction—the clinical term for crying-it-out—effectively reduced bedtime resistance and the frequency of nighttime wakings, concluding that it “has a strong record of accomplishment.” The two published clinical trials on graduated extinction, the technique popularized by sleep researcher Richard Ferber, which involves leaving your baby to cry for increasing periods of time (but not necessarily all night), was deemed successful, too, but it takes longer. None of the studies found side effects associated with sleep training. In a 2012 randomized clinical trial, Australian researchers followed up with 173 6-year-olds who had been sleep trained as babies, some of whom with graduated extinction, and found that they were no different than non-sleep-trained 6-year-olds with regards to emotional development, psychological health, parent-child closeness, and parental attachment.
And it’s not just that a short stint of sleep training isn’t harmful—it could actually be beneficial. People tend to underestimate the importance of sleep, but it’s absolutely crucial for healthy development, and longitudinal studies have suggested that sleep-deprived infants often go on to become sleep-deprived children. (Here’s some info on how much sleep children of different ages need.) Sleep deprivation affects parts of the developing brain involved in regulating emotions and thinking logically. Kids who don’t sleep well are also more likely to injure themselves. Sleep-deprived adults, as in parents who are up at all hours of the night tending to sleepless babies, are much worse at deciphering emotional cues and being emotionally expressive themselves—problems that could potentially threaten the parent-child attachment bond. Several trials have also found that sleep training reduces the risk of maternal depression—by as much as a factor of three—which is (actually!) chronically stressful for kids; a 2009 study reported that infants of depressed moms were more likely to be anxious and socially disengaged than were infants of healthy moms.
Crying-it-out is not for every parent, I know. But desperate parents—or parents who just want to be done with the 2 a.m. wake up— should feel fine trying the method. It’s not just that there’s no evidence of harm in crying-it-out—there is some solid evidence of no harm. When sleep training works, and research suggests it often does, it can provide long-term benefits for the entire family—giving babies the sleep they need to develop into healthy toddlers and giving parents the rest they need to be sensitive, confident, and happy caregivers.