Oxytocin, an endocrine hormone that has the function of releasing breast milk, has recently been shown to have the function of facilitating interpersonal relationships and enhancing memory and learning abilities.This time, the group of Kyoto University and Azabu University investigated the fluctuation of oxytocin secretion in an individual for mothers who are raising a 2-9 month old baby at the first birth, and the fluctuation value and how it feels in the interpersonal scene. The relevance was examined.
As a result, there were large individual differences in oxytocin fluctuations before and after the act of "breastfeeding" or "holding an infant", while mothers who increased oxytocin after breastfeeding were more sensitive to facial expressions (happy). It turned out to be insensitive to unpleasant facial expressions (anger).
In the experiment, the oxytocin level was measured before and after either "breastfeeding" or "holding the baby", and then the "facial expression detection task" (detecting only one of the eight facial expressions) and A "facial expression judgment task" (to judge the facial expression that dynamically changes from no expression and to evaluate the strength of comfort / discomfort) was carried out.Analysis of oxytocin levels revealed that there were large individual differences in oxytocin fluctuations in both the "breastfeeding" group and the "holding an infant" group.On the other hand, in the "breastfeeding" group, mothers who increased oxytocin after breastfeeding had higher accuracy in perceiving pleasant facial expressions (happy) and less accurate in perceiving unpleasant facial expressions (anger) in the "facial expression detection task". At the same time, the feeling of a happy facial expression was weak in the "facial expression judgment task".
Breastfeeding is said to reduce the stress of caregivers and increase the feelings of pleasure for the baby, but this study shows that breastfeeding does not increase oxytocin levels in all mothers, and that is the case with others. It was also shown to be related to how the facial expressions are felt.In the future, it will be an issue to verify how these individual differences in the mental and physical characteristics of the caregiver affect parents and children.
Paper information:[Biology Letters] Breast feeding dynamically changes endogenous oxytocin levels and emotion recognition in mothers
