A study in Japan has shown that a crying baby’s heart rate drops very quickly if the infant is picked up and carried by a familiar caregiver. Just holding the baby won’t do; the infant has to be picked up and carried.
Lead researcher and neurobiologist Dr. Kumi Kuroda, of the Riken Brain Science Institute, theorized that this is the same response that we see in other mammals, including puppies, kittens and lion cubs, all of which relax and go limp when picked up and carried with their mothers’ mouths.
The research team studied babies, as well as mouse pups, and researchers obtained similar results for both. Electrocardiogram measurements were used to monitor the heart rates of the babies and the mouse pups after they were picked up and carried, and their hearts slowed almost immediately. It took about one second for the heart rate of the mouse pups to drop, and about three seconds for the infants’ heart rates to drop.
Babies as well as mice also stopped voluntary movements after they were carried, and mice stopped emitting ultrasonic cries. This was the first time that researchers took actual measurements of babies’ physiologic responses to being picked up and carried by a familiar caregiver.
Researchers studied babies under 6 months old. The most pronounced favorable response to being carried was seen in babies who were 3 months and younger. As far as humans, Kuroda believes that this is a mechanism unique to a baby’s physiologic makeup, as adults usually cannot calm down that fast.
Dr. Kuroda noted that the study could offer valuable insight for parents, as the results illustrate that babies actually calm down tremendously when picked up and carried by mom, dad, or another familiar face. Kuroda added that understanding this method of calming a baby could prove important for caregivers, as unstoppable crying is the main risk factor for child abuse in young babies.
The study was published in April, 2013 in the journal Current Biology.
In the case of a baby who does not calm down upon being carried, caregivers must then eliminate common possible reasons for baby’s unrest, including hunger, needing a diaper change, sleepiness, being cold or too warm, a gassy stomach, being overstimulated and tired, or even simply needing to be tenderly reassured and given attention. Gone are the days when parents were told by child experts to let baby “cry it out” and to restrain their response to crying, or baby would become spoiled.
Nowadays, we know that babies develop a stronger sense of security, and actually cry less as they get older, if parents respond to their cries promptly and lovingly. After a while, you will get to know your baby’s distinct cries and will be able to better recognize what she or he needs.
By Lisa Pecos