Babies whose mothers regularly use language to describe what their child thinks or feels have higher levels of the hormone oxytocin, according to a new study led by UCL researchers.
Oxytocin, a hormone involved in a variety of psychological processes, plays an important role in social relationships, such as the development of parent-child bonding, and the formation of trust and social understanding throughout life.
For the research, published in Development and Psychopathology, 62 new mothers between the ages of 23 and 44, and who had a baby between three and nine months old, were filmed interacting naturally with their baby for five minutes.
The researchers analyzed the videos to see how well the mother accurately referred to her baby’s internal experience (e.g., her thoughts, feelings, desires, and perceptions) during the interaction.
They also collected saliva samples from the baby and measured the level of the hormone oxytocin.
When the relationship between these two measures was analyzed, the researchers found a positive correlation.
Lead author Dr Kate Lindley Baron-Cohen (UCL Psychology and Language Sciences) said: “The hormone oxytocin has long been known to be involved in intimate social relationships, including the attachment bond between a mother and her child. It is also known that a mother’s attunement to her baby’s thoughts and feelings during the first year of life is a long-term predictor of the child’s social and emotional development. But the pathways underlying these effects. are not clear.
“We have discovered, for the first time, that the number of times a mother talks to her baby about her baby’s thoughts and feelings is directly correlated with her baby’s oxytocin levels. “This suggests that oxytocin is involved in regulating children’s early social experience, and this in turn is determined by the way parents interact with their baby.”
For example, when a child demonstrates interest in a toy, a parent showing understanding of his or her child’s internal state might say, “Oh, right?” as this toy” or “You are enthusiastic” and they could imitate their children’s actions or facial expressions. In this way, parents reflect the child’s internal experience, and new results now reveal that this also influences the baby’s oxytocin system.
The team also found that mothers who experienced postpartum depression referred less to their babies’ internal states than mothers who did not experience depression.
Dr Lindley Baron-Cohen said: “This study demonstrates a new psychobiological link between mothers and their babies, in which the mother’s emotionally sensitive speech is reflected in her baby’s hormone levels.
“This highlights the key role mothers play in their children’s early development and indicates how mothers suffering from depression could be supported to facilitate their children’s social development.”
This research was funded by the National Institute for Health Research (NIRH) ARC North Thames, the Lord Leonard and Lady Estelle Wolfson Foundation, the Wellcome Trust, the University of York, the Fund for Psychoanalytic Research through the American Psychoanalytic Association, the International Psychoanalytic Association, Michael Samuel Charitable Trust, Denman Charitable Trust and Galvani Foundation.