Kissing, food-sharing and other spit-swapping activities help babies identify close relationships and recognize people they can depend on for assistance, according to a study by MIT and Harvard University researchers. Infants expect people who engage in saliva-sharing experiences to help one another in times of distress.
For infants, toddlers, and children, one sign of an especially close relationship is if two people do something that involves exchanging saliva, like taking bites from the same piece of food.
For infants, toddlers, and children, one sign of an especially close relationship is if two people do something that involves exchanging saliva, like taking bites from the same piece of food.