By Robert Preidt, health day reporter
FRIDAY, Jan. 21, 2022 (HealthDay News) — Sharing food and hugging are two ways babies know who they can count on to care for them, according to a new study.
The revealing index common to both is surprising: saliva.
“Babies do not know in advance what relationships are the near and morally obligated, so they must have a way of learning this by watching what is happening around them,” said study lead author Rebecca Saxe, of the Massachusetts Institute’s McGovern Institute for Brain Research. of Technology.
For the study, his team observed babies and toddlers as they watched staged interactions between people and puppets. The babies were 8 1/2 to 10 months old and the toddlers 16 1/2 to 18 1/2 months old.
In one series of experiments, a puppet shared an orange with an actor and then threw a ball back and forth with another actor.
After the pups watched these interactions, the researchers observed their reactions when the puppet showed distress while sitting between the two actors.
Based on the results of animal studies, they expected young people to first look at the person they hoped to help.
Not so. The researchers found that the children were more likely to look towards the actor who shared food with the puppet, rather than the one who shared a toy.
In the second set of experiments, which focused on saliva, the actor either placed his finger in his mouth and then the puppet’s mouth, or placed his finger on his forehead and then on the puppet’s. When the actor then expressed his distress by standing between the puppets, the children were more likely to stare at the puppet he had shared saliva with.
The results suggest that sharing saliva helps infants learn about Social relations, the researchers said. It helps babies identify the people most likely to provide for them.
“The general skill of learning social relationships is very useful,” said lead author Ashley Thomas, a postdoctoral student at MIT. “One of the reasons why this distinction between thick and thin [relationships] could be important for infants in particular, especially human infants, who depend on adults longer than many other species, is that it could be a good way to determine who else can provide the support they depend on to survive. »
The researchers plan similar studies with infants in cultures that have different family structures. They also want to use brain imaging to determine which parts of the adult brain are involved in saliva-based assessments of social relationships.
The results were published on January 20 in the journal Science.
SOURCE: MIT, press release, January 20, 2022
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