The Science Behind "Cry It Out"

Molly Smith Metzler’s Cry It Out features new mothers Jessie and Lina building a friendship over their shared experiences parenting their newborns, bonding despite their very different socioeconomic backgrounds and tackling a variety of parenting dilemmas.

While mothers of the past relied on advice passed down from female elders and their own intuition, in today’s advanced society, science has shaped more of our approach to parenting. In Cry It Out, both Jessie and Lina have an intuitive opposition to extinction-method (‘cry it out’) sleep training; but while Jessie reluctantly plans to sleep train according to her doctor’s suggestion, Lina is skeptical about the doctor’s advice. However, both women appear inclined to let each other go their own way, with their need for human connection outweighing their opinions about parenting.

Since the natural instincts of new parents are often to prevent their children from feeling any distress, the medical recommendation to avoid comforting a crying baby may seem appalling. Some parents and child advocates believe that allowing their infants to “cry it out” will cause permanent harm or interfere with a child’s attachment process. These ideas make sense, but are they backed by evidence? What does the science say?

Sleep Training: Let Them Cry It Out

Sleep training as first introduced by Dr. L Emmett Holt in 1894 consists of simply putting a child to bed and leaving them be. The idea is that a baby will cry for a while and then realize that no one is coming, prompting them instead to self-soothe and fall asleep. The next night, the crying period gets shorter, and eventually the child is able to fall asleep without parental help.

The method was later refined by Richard Ferber in his 1986 book Solve Your Child’s Sleep Problems. He recommends gradually increasing the amount of time a child is left alone to cry each night. This method appears to be less traumatic to the child and may assuage some of the parents’ anxiety about leaving their child alone.

Many parents, like Lina, feel that abandoning their child in this way is too cruel to be worth a good night’s sleep. On the other hand, sleep deprivation has great physical and psychological risks for parents and children. The question researchers have to consider is whether the positive effects of better sleep outweigh the negative effects of the sleep-training process.

The Verdict on Sleep Training

While the stress of being separated from caregivers is well-documented in infants, its long-term effects are less well understood. The relationship of stress to long-term health effects is a complex one. Many other factors, including secure attachment and a positive parent-child relationship, can influence or even remove the effect of stress on long-term development.

Perhaps the most convincing evidence on sleep training comes from a 2012 study of five-year-olds. While this study suffered a number of flaws common to parenting studies, its primary conclusion is trustworthy enough: at five years old, there were no significant differences between children who were sleep-trained as infants and children who weren’t.

Metzler’s Conclusion: You Do You, Girl

The overall takeaway here, and one also expressed by Metzler, is that plenty of people have strong opinions about the “right” choices for mothers to make. Thankfully, in the case of sleep training, neither choice is a particularly wrong one. Sleep-training a child is unlikely to harm them, but choosing not to sleep-train a child is also unlikely to cause harm. Every family is different, and each family has to decide what is best for them and their infant.

While some choices, like vaccinating your baby, are very clearly the science-supported "right" choice, the Ferber and other "extinction" methods of sleep-training are not the only correct option. Babies who are left to "cry it out" and babies who are comforted to sleep or learn to sleep via other non-extinction methods grow up with similar outcomes.

Although Jessie and Lina have different plans when it comes to sleep-training, they find that it is more important for them to have each other’s support as they face all the trials of parenting newborns. Rather than being left alone to cry it out, they are able to seek the comfort of a new friend in a similar situation.

Kitty Geoghan