Are you currently cradling a baby in your arms? Then probably with the left one. This is the case for most people, explained Audrey van der Meer from the Norwegian University of Science and Technology (NTNU) in Trondheim. Artistic depictions also reflect this behavior: “The Virgin Mary is usually depicted cradling the baby Jesus in the crook of her left arm.”
According to studies, the preference to keep left has been evident in all cultures and ethnic groups and over centuries. Van der Meer now examined existing data and meta-analyses on the topic for a review article. One theory says that a baby is mainly carried on the left arm because it can then hear the heartbeat better: In almost all people, the heart is on the left side.
Another theory is related to sensory perception: the left ear and eye are used to receive information about the baby’s emotional state – signals from the left are sent to the right hemisphere of the brain, which is specialized in interpreting emotions and faces.
According to van der Meer, there is most likely a much simpler reason: you want to have your “better” arm free so you can continue using it – and “9 out of 10 people in the world are right-handed.” There are many pictures of Prince William carrying one of his children as a baby with his right arm. “He’s left-handed,” said van der Meer. Princess Kate, on the other hand, is right-handed and, like most people, tends to hold babies in her left arm.
The fact that the left arm is favored only applies to babies: “As children get bigger and heavier, most people tend to carry them with their dominant and stronger arm,” it said.
Van der Meer’s review was published online in the journal “Infancy” in December.
