So there you are, celebrating the holidays, and this year one of the guests is an infant. As everyone is chatting and passing the olives before dinner, you notice that the baby stretches out his little arms toward some people but not others. Pay attention. The kid is very likely a good judge of character.
In a study published recently in the journal Nature, scientists tested 6- and 10-month-old babies to see how smart they are about judging people by how they act toward others. The babies, it turns out, prefer those who are helpful rather than unhelpful toward a third party (that is, not the baby himself). The findings suggest that children evaluate those around them far earlier than previously thought, deciding “who is friend and who is foe, who is an appropriate social partner and who is not,” write graduate students Kiley Hamlin, Karen Wynn and psychology professor Paul Bloom of Yale University.
That might give babies the biological tools that serve as the basis for moral reasoning later in life. “6- and 10-month-old infants," conclude the scientists, "prefer an individual who helps another to one who hinders another, prefer a helping individual to a neutral individual, and prefer a neutral individual to a hindering individual.”
In their experiment, the scientists opened a curtain to reveal a stage where a green wooden slope was front and center. As the babies sat on their mother's lap, a wooden block with big, googly eyes tried to climb a hill. It was either aided by another wood block, the “helper,” who pushed it from behind, or pushed down by a third block, the “hinderer.” Then the babies were given a choice about whom—helper or hinderer—to reach for. “Infants robustly chose the helper,” even though it was just a geometric shape, found the scientists, “indicating that they held distinct impressions of the two characters on the basis of their actions towards the climber.”
Then the scientists tested whether the babies had really understood what they had witnessed. They set up the scene so that the climber first approached the helper and then the hinderer. The 10-month-olds looked longer at the latter; since infants generally gaze longer at the unexpected or surprising, that indicated that they couldn’t get their little brains around the fact that the climber was approaching someone who had blocked him from reaching his goal. Six-month-olds didn’t get it, though, showing no surprise that the climber approached the hinderer. That suggests that they were too young to attribute a preference to the climber.
The findings are the first evidence that babies’ social preferences “are influenced by others’ behavior toward unrelated third parties,” conclude the scientists. Lesson: if you want kids to like you, don’t do anything mean to someone else while they’re watching. Even 10-month-olds will hold it against you.