Rather than stumbling out of bed in the early morning after finally soothing their crying baby, sleep-deprived parents may want to consult the latest scientific literature on the transport of nesting mammals.
In an effort to help those who are numb from sleep loss, researchers conducted a series of experiments to find out which approach to crying babies calms them best.
After filming parents cuddling their babies, carrying them, rocking them in a stroller and laying them down, the scientists arrived at an optimal strategy, or at least one that performed better than the others.
Writing in Current Biology, the team recommends parents pick up their crying baby, walk with them for five minutes – without sudden stops or abrupt changes in direction – then sit and hold them for five to eight minutes before to rest it. again.
“Excessive crying, especially at night, is found to be a major source of parenting stress,” said Dr Kumi Kuroda, from the Riken Center for Brain Science in Saitama, Japan. “This method of about 15 minutes is worth trying before they start to worry seriously about what’s wrong with the baby.”
The idea emerged from research on altricial mammals – those that are helpless at birth – such as cats, dogs, mice, squirrels and, notably, humans. Studies show that when carried by their mother, the young become more docile, an effect called the “carrying response”. Since animals often move their young to escape imminent danger, the response may have evolved through improved offspring survival rates.
Researchers used video recordings and baby heart monitors to categorize four different approaches to soothing crying babies: holding the child sitting up, putting him in a bed, holding him while walking, or rocking him in a stroller or similar. Crying only decreased when babies were in motion, whether rocked or carried. Sitting with the baby or putting him in a bed did nothing to stop the tears.
After being carried for five minutes, all of the crying babies had stopped crying and nearly half had fallen asleep, the researchers report. But even for the parents whose babies settled in, the danger was far from over. About a third of babies woke up almost as soon as they were put back to bed.
To find out what woke the infants, scientists looked at heart monitor data. This showed that babies’ heart rates sometimes increased enough to wake them when physical contact with the parent was broken. Trying to lay the baby down more gently made no difference. What helped was sitting with the sleeping baby for five to eight minutes after walking around to get them into a deeper stage of sleep.
While the approach worked better than the others, scientists don’t claim it’s a magic bullet for sleep-deprived parents. The research on 21 infants in Japan and Italy is “exploratory”, with results that need to be verified in larger studies.
“Babies can have sleepless nights for very different reasons,” said Gianluca Esposito, professor of developmental psychology and co-author of the paper at the University of Trento. “If the baby has a stomach ache, I don’t think it will do much. Unfortunately, I think many parents will still have sleepless nights. It’s part of being a parent.
Professor Ian St James-Roberts, who studied soothing techniques for crying babies at the UCL Institute of Education, said he hoped the team would continue their work. “Other studies on the use of parental carrying do exist and generally indicate that babies cry less when carried,” he said. “It would be good to know if these new, more detailed guidelines make things any better.”
“Crying is an important and normal method of communication for babies – crying gives your baby a voice,” said Dr Betty Hutchon of the Brazelton Center UK. “Babies have different cries for different needs such as tiredness, discomfort, hunger, or a desire to be held and played with. Over time, parents learn by trial and error and experience what it means. There is no single response or strategy that meets all the needs of crying babies at all times – different responses will be appropriate at different times.