Sharing saliva shapes babies’ understanding of relationships

Early in life, babies and toddlers need to know who is going to feed them and keep them safe. Older children are more verbal and better able to distinguish their relationships, but preverbal babies and toddlers cannot understand as easily which relationships are the closest they can rely on. In place, they are wired to understand how certain interactions involve different categories of relationships.

Babies and toddlers produce lots of fluids to control their bodies. They also watch everything we do and usually want a slobbery bite out of everything we eat.

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Through thick and thin

In one new study from the Massachusetts Institute of Technology (MIT)the researchers wanted to demonstrate that the distinctive behaviors that occur between babies and toddlers and adults in their world help them know intuitively who is or is not familyso who is most likely to take care of it.

The researchers postulated that babies and toddlers could be distinguish between those who do or do not share saliva, as a determinant of who is a “thick” relationship (such as family, parents, siblings, and grandparents) or a “thin” relationship (other adults, such as service providers guard and nannies). Family members typically have strong levels of mutual attachment, obligation and responsiveness – and according to anthropologists, more willingness to share bodily fluidslike saliva.

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“One of the reasons why this distinction between thick and thin might be important for infants in particular, especially human infants, who are dependent on adults longer than many other species, is that it might be a good way to determine who else can provide the support they depend on to survive,” says lead researcher Ashley Thomas, a postdoctoral psychology fellow at MIT who studies what babies and young children understand about the complexities of their social world. This inspired both the question of whether infants distinguish between these types of relationships and whether sharing saliva might be a really good cue they could use to recognize them,” Thomas said in MIT News.

For babies, sharing saliva equals intimacy

MIT researchers carefully designed a series of experiments to determine whether babies and toddlers wait for people who share saliva help each other when in distressmuch more so than when people share toys or interact in other ways that don’t involve sharing saliva.

In their experiments, the researchers observed nearly 300 toddlers (16.5 to 18.5 months) and babies (8.5 to 10 months) as they watched brief videos depicting the sharing of saliva and other activities between actresses and puppets.

In one video, a woman rolled a ball back and forth with a blue puppet. Next, another woman put a slice of orange in her mouth before giving the blue puppet a bite of the slice, then putting it back in her mouth to finish it, demonstrating that the woman and the blue puppet shared some food. saliva.

Then the puppet cried – and when it happened, nearly 4 in 5 babies and toddlers looked first and looked longer at the woman who had shared a bite of her orange – and spat – with the puppet , expecting that person to comfort the puppet. “Both of these interactions are perfectly friendly and pro-social,” says Thomas, “but taking bites of the same food suggests a more intimate relationship than just playing ball.”

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To make sure it wasn’t just the sharing of food that seemed to trick babies and toddlers into thinking there was a “thick” connection, the researchers created another video that showed a different woman sharing only his saliva. In the video, she put her finger in her mouth, then put it in a purple puppet’s mouth, then put it back in her own mouth.

When the two women were depicted with this new purple puppet as she began to cry, infants and toddlers looked at the two women just as often. This suggested to the researchers that babies and toddlers did not perceive the particular woman sharing the food as particularly helpful since both women had shared saliva with the puppets. Instead, the researchers assumed it was the relationship with the puppet that really mattered.

“Saliva-sharing interactions provide externally observable cues of thick relationships, and young humans can use these cues to make predictions about subsequent social interactions,” the researchers report. The results suggest that saliva helps babies and toddlers quickly identify who of those around them falls into the “thick” relationship category to determine who is most likely to offer help, and that they can distinguish closeness very early in life.


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