The maternal body odor not only promotes the bond between mother and child, but can also help infants make contact with new people. This is shown by a study in which babies interacted with someone they did not know when they were around seven months old. If their mother’s t-shirt was in front of them, they were more attentive and open-minded towards strangers, and their brainwaves synchronized to the same extent with those of their counterparts as they normally did with those of their mother. The mother’s scent could thus help prepare toddlers for social interactions.
From birth, the smell of their mother gives babies a feeling of security and security. Previous studies have shown that newborns can recognize their mother by odor and that the chemical signals from maternal body odor help reduce pain in children. In addition, the familiar smell promotes visual awareness in babies and helps to build mother-child bonds.
Worn T-shirt as a source of odor
A team led by Yaara Endevelt-Shapira from the Center for Developmental Social Neuroscience in Israel has now investigated to what extent the maternal odor also affects the babies’ interactions with other people. To do this, the researchers invited 62 mothers with their seven-month-old babies to the laboratory. In a first experiment, mother and child sat across from each other and were allowed to interact freely with each other. Meanwhile, the researchers measured their brain waves using an EEG. In agreement with earlier, similar experiments, it was found that in this setting certain brain waves from mother and child synchronized with one another. If, on the other hand, mother and child sat with their backs at a similar distance from one another, the synchronization was significantly weaker.
In the next step, a person unknown to the child took the place of the mother. It was a different mother from the experiment who was about the same age as the baby’s own mother and had a child of about the same age. As with the mother-child interaction before, the stranger and the baby sat across from each other and were free to interact with each other while their brain waves were recorded. There was a T-shirt in front of the child – either a fresh one or one that the mother had worn two nights earlier and that gave off her body odor.
More attentive, happy and open
The result: children who could smell their mother’s scent while interacting with the stranger were more attentive and open-minded compared to children in front of whom an unworn T-shirt was lying in front of them. They looked more at their counterparts, appeared happier and made more attempts to establish contact. The EEG data showed: While there was hardly any synchronization between the brainwaves of the stranger and the baby without the maternal odor, the synchronization in the test run with the T-shirt was similar to that between the baby and its own mother.
The researchers also analyzed the extent to which the baby’s increased visual attention, positive arousal, and approaching behavior all contributed to the synchronization. “Although there was a significant increase in all three behaviors in the presence of maternal body odor, only visual attention was directly related to the increase in brain synchronization between the infant and the stranger,” the researchers write. “We suspect that maternal body odor increases the infant’s awareness of social stimuli such as looks, facial expressions, laughter and gestures, which in turn cause the brain waves to readjust.”
Soothing odor even in the mother’s absence
Exactly which areas of the brain are involved in the synchronization can only be determined to a limited extent from the EEG data. According to the researchers, however, the results suggest that, among other things, parts of the temporal lobe are involved, which play an important role in social interactions. “Even if caution is required when determining specific brain areas, our results could indicate that odor-sensitive areas modulate the neurological behavioral dynamics of infants in order to strengthen the synchronization between the brains,” the researchers say. “This could serve to tune infants to social partners in the group, familiar social contexts and the various components of social experience.”
The mother’s odor therefore serves as a safety signal for the infant. Calmed by this signal, the child has to spend fewer resources on danger signals and can concentrate more on social engagement and emotional processing. Unlike sight, voice or touch, the mother’s scent can accompany the baby even in her absence. This can make it easier for young children to get involved with new people in a social context.
Source: Yaara Endevelt-Shapira (Center for Developmental Social Neuroscience, Israel) et al., Science Advances, doi: 10.1126 / sciadv.abg6867