Comments Subscribe to Personal Liberty News Feed Subscribe to Personal Liberty

Letting A Baby ‘Cry It Out’ Goes Against Biology

SAITAMA, Japan, (UPI) — Parents are often advised to let a baby “cry it out” in a crib but Japanese researchers say to let babies cry and not pick them up goes against biology.

Kumi Kuroda of the RIKEN Brain Science Institute in Saitama, Japan, said there is a very good reason mothers often carry their crying babies to help them calm down — infants experience an automatic calming reaction upon being carried, whether they are mouse or human babies.

The study showed an infant calming response to carrying is made of a coordinated set of central, motor and cardiac regulations and an evolutionarily conserved component of mother-infant interactions, the researchers said.

“From humans to mice, mammalian infants become calm and relaxed when they are carried by their mother,” Kuroda said in a statement.

Kuroda said the idea for the study came while cleaning the cages of her lab’s mouse colony.

“When I picked the pups up at the back skin very softly and swiftly as mouse mothers did, they immediately stopped moving and became compact. They appeared relaxed, but not totally floppy, similar to a human baby,” Kuroda said.

Once the researchers found an ECG monitor electrodes small enough to use on conscious mouse pups, the researchers found when the baby mice were carried their heart rates slowed, they became calm, relaxed and stopped crying.

The study, published in the journal Current Biology, found the heart rates of human babies slowed immediately upon being carrying — same as mice.

UPI - United Press International, Inc.

Since 1907, United Press International (UPI) has been a leading provider of critical information to media outlets, businesses, governments and researchers worldwide.

Facebook Conversations

Join the Discussion:
View Comments to “Letting A Baby ‘Cry It Out’ Goes Against Biology”

Comment Policy: We encourage an open discussion with a wide range of viewpoints, even extreme ones, but we will not tolerate racism, profanity or slanderous comments toward the author(s) or comment participants. Make your case passionately, but civilly. Please don't stoop to name calling. We use filters for spam protection. If your comment does not appear, it is likely because it violates the above policy or contains links or language typical of spam. We reserve the right to remove comments at our discretion.

Is there news related to personal liberty happening in your area? Contact us at


Sign Up For Personal Liberty Digest™!

PL Badge

Welcome to,
America's #1 Source for Libertarian News!

To join our group of freedom-loving individuals and to get alerts as well as late-breaking conservative news from Personal Liberty Digest™...

Privacy PolicyYou can opt out at any time. We protect your information like a mother hen. We will not sell or rent your email address to anyone for any reason.