Family

It’s Absurd to Claim That Smarter Babies Sleep Poorly at Night

A baby in his crib, with a graduation-cap outline
Photo illustration by Natalie Matthews-Ramo/Slate. Photo by Artfoliophoto/iStock/Getty Images Plus.

The Kids is Slate’s science-based parenting column, assessing the latest research around children’s health, development, and well-being.

A new parenting claim made the rounds on social media this week, and it was a doozy. “Smarter Babies Need Less Sleep and Wake Up Through the Night, Claim Experts,” touts the headline of a piece published by the Australian website Healthy Mummy. The piece, based on a 2015 BuzzFeed article, has now been shared 363,000 times on social media. On Thursday, the Irish Independent jumped onboard with a similar piece titled “Why It’s Actually a Good Thing if Your Baby Doesn’t Sleep Through the Night.”

The arguments these articles make, and the assumptions they are based on, are so badly flawed, I almost don’t know where to begin. But the richest whopper is the central claim, summed up in this quote by University of Bristol developmental physiologist Peter Fleming: “There is absolutely no evidence whatsoever that there is any benefit to anybody from having a child that sleeps longer and consistently.” Actually, there’s quite a bit of evidence. Let’s start with this 2010 study conducted by University of Montreal researchers, in which 60 parents kept sleep diaries when their babies were 12 months and 18 months old and then researchers later tested the children’s mental skills as toddlers. They found that “higher proportions of total sleep occurring at night time, at both 12 and 18 months, were related to better performance on executive tasks.” There’s also this 2011 study in which researchers from New Zealand monitored the sleep of 52 infants for a week using sensors as well as parent diaries and questionnaires, finding that “sleep efficiency, and having a higher proportion of total sleep at night, were significantly correlated with age as well as stages of cognitive and motor development.”

In 2017, researchers reviewed all of the scientific literature on the topic, concluding that there is a “positive association between sleep, memory, language, executive function, and overall cognitive development in typically developing infants and young children.” A number of animal studies support the notion that sleep promotes memory, learning, and improved cognition, too: Animals deprived of sleep during infancy, for instance, wind up with smaller cerebral cortices as adults. In sum, “the scientific literature on infant sleep completely contradicts the ridiculous claims made in these articles,” says sleep consultant Arielle Greenleaf, founder of Massachusetts-based Expect to Sleep Again Sleep Consulting.

There’s also a clear benefit to parents when babies sleep better. As I explained in a previous column on sleep training, multiple clinical trials have reported that interventions that help babies sleep better at night reduce the risk for maternal depression by as much as a factor of three.

So it’s unclear why Fleming believes there is “absolutely no evidence” that better infant sleep provides “benefits for anybody.” It’s also unclear why the Healthy Mummy piece touts that “gifted children need fewer hours of sleep to operate than their peers do,” because no studies come close to backing up that claim. (It’s worth noting that the site appears more concerned with marketing weight-loss techniques and nutritional products than publishing sound journalism.) If anything, since smarts correlate with longer sleep, it would be more reasonable—albeit not quite accurate—to argue that gifted kids probably need more sleep than their peers.

No doubt, there’s an alluring message here for exhausted parents: that your suffering may ultimately produce a superior child, and since this is all seemingly beyond your control, you should surrender and go with the flow—never mind how little sleep you get.

But there’s also a flawed underlying assumption in these pieces. Fleming says that waking up at night is normal but “doesn’t fit in with our 21st-century expectations.” Actually, Fleming misunderstands our 21st-century expectations. Parents who do sleep training don’t expect or want their babies to sleep through the night without ever waking up; we know babies inevitably wake up, just as adults do, because that’s how sleep cycles work. The goal of sleep training is instead to help babies and children develop ways to self-soothe and go back to sleep without needing a parent to hold, feed, or sing to them. And it enables us to get the sleep we need, too, and be better parents in the morning.

Fleming’s main and most offensive point comes through a quote at the end of the BuzzFeed and Independent articles. “If we go back to evolutionary history of humans, babies spent all their time in close and continual contact with their mum, they get carried around everywhere,” he explains. “If the baby is constantly with mum, the idea that they need to sleep for long periods of time doesn’t really arise.” Aha! That’s the misogynistic crux of the problem for him, then: Mothers don’t constantly carry their babies around anymore. Now, mothers have the audacity to do things like work and put their children in day care. If only mothers would rearrange their lives around their children and not vice versa, sleep schedules would be moot. But that’s an absurd proposition coming from someone who finds it just as simple to rearrange basic facts about sleep science to make people feel guilty.