Babies Use Kissing and Sharing Their Food as Signals to Interpret Their Social World, Says New Study
Sharing food and kissing are among the signals babies use to interpret their social world, according to a new study.
Social & Lifestyle
Learning to navigate social relationships is a skill that is critical for surviving in human societies. For babies and young children, that means learning who they can count on to take care of them.
MIT neuroscientists have now identified a specific signal that young children and even babies use to determine whether two people have a strong relationship and a mutual obligation to help each other: whether those two people kiss, share food, or otherwise share saliva.
In a new study, the researchers found that babies actually expect those who share saliva to come to one another’s aid if any one person is in distress—much more so than when people share toys or interact in other ways that do not involve the mouth.
The findings suggest that babies can use these cues to try to figure out who around them is most likely to offer help, the researchers say.
“Babies don’t know in advance which relationships are the close and morally obligating ones, so they have to have some way of learning this by looking at what happens around them,” says Rebecca Saxe, the John W. Jarve Professor of Brain and Cognitive Sciences, a member of MIT’s McGovern Institute for Brain Research, and senior author of the new study in the journal Science.
In human societies, people typically distinguish between “thick” and “thin” relationships. Thick relationships, usually found between family members, feature strong levels of attachment, obligation, and mutual responsiveness. Anthropologists have also observed that people in thick relationships are more willing to share bodily fluids like saliva.
“That inspired both the question of whether infants distinguish between those types of relationships, and whether saliva sharing might be a really good cue they could use to recognize them,” Thomas says.