You may not have noticed, but up to 85 percent of the time, mothers tend to carry their babies on the left side of the body, especially when you are cradling (even those who are left-handed). It may seem arbitrator, as sometimes the place of a hand, sometimes of the opposite, but there is a strong tendency to do it more on the left side to the right.
What is it? Even though we believe that it is casual and has no greater importance, this preference has a scientific explanation very interesting. It is an instinctive behavior in which are involved the cerebral hemispheres of the mother and the baby, and is related to the strong emotional bond that is established between both in the first months of life.
In a study published in the journal Nature, Ecology and Evolution, researchers from Russia, Australia and the united States studied the lateralization of mother-child interactions in various mammalian species to discover what is behind this preference for load or carry the offspring on the left side of the body.
The left hemisphere of the brain is more rational, is related to language processing, calculations, etc, While the right hemisphere is more emotional, associated with social processing, emotion, facial recognition, spatial orientation, and music.
As you know, motor functions of the left side of the body are controlled by the right hemisphere of the brain, while the right, by the left hemisphere. That is why the tendency to cradle the baby on the left side of the body is directly related to the hemisphere is more emotional, which results in the construction of the affective bond mother-son.
This preference reflects the processes of socio-emotional that occur in the first few months of baby's life. Let us remember the importance of the mother and the father interact with the baby, talk to him, though still not able to understand them and smile at the baby, as well as that mother what to look at while you are feeding.
The bias side on the left side at the time of carrying the baby in her arms has an advantage to social processing, controlled by the cerebral hemisphere the right. Facilitates the visual recognition of the facial expressions of the baby, and optimizes the surveillance of the mother by the address of the sensory information predominantly to the right hemisphere of the mother.
A previous study from the University of Sussex published in 2004 supports this assertion, that between 70 and 85 per cent of the women and girls show a bias to hold their babies, or wrists, on the left side of his body.
Humans are not the only ones who do
To test this theory, researchers led by the zoologist Karina Karenina studied the behaviors of lateralization of ten other species of land and marine mammals, including oxen, reindeer, antelopes, horses, walruses, sheep, and three species of whales and two species of kangaroo.
By doing so, they discovered that, like humans, in all species studied, the mothers had a preference similar. But the move by themselves, most of the time they are pups that prefer to keep their mothers on their left side. Except in situations of stress or danger in which the offspring are changed aside for the protection of his mother.
In nature, the young need to know that your mother is at all times present and when there is a danger, a parent should closely monitor your child.
Human mothers cradling their babies on their left side while they are young and vulnerable, but this may change as the children grow older and become more independent, suggest the researchers.
Although this seems to be the most studied, there are other theories with regard to the lateralization of the left side of the body to carry the babies. As mentioned in a previous post, the American psychologist Lee Salk explained that the put that hand, instinctively, because that way the babies could be close to the heartbeat of the parents.
Another reason is that most people are right-handed, therefore, to place the baby on the left side, we free up our side more and more skillful to the hour to make things. Although this theory would be refuted by the above that suggests that most of the times mothers are left-handed also choose the left side to cuddling their babies.
Have you paid attention to which side is the more you use to carry the baby? Does it match the study?