Babies Develop a Sense of Fairness at 15 Months Old, Study Suggests

Family Matters on 10.11.11

You would never say you have a favorite child, but kids often see it differently -- and new research suggests that children as young as 15 months old not only recognize unequal treatment, but may also connect it to their willingness to share.

The study, led by researchers from the University of Washington and the Max Planck Institute for Evolutionary Anthropology, consisted of two phases: In the first, babies watched a video of an adult distributing crackers equally and then unequally to two other adults followed by a second video of the same action repeated with milk. Researchers found that babies looked longer when the foods were divided unequally -- a behavior that indicates the babies "expected an equal and fair distribution of food, and they were surprised to see one person given more crackers or milk than the other," said co-author Jessica Sommerville on Science Daily.

In the second part of the experiment, the babies chose between two different Lego toys -- when the researchers asked to share one of the toys, they noted whether the baby shared the toy he had picked for himself (the "preferred toy") or the unwanted one. Babies who shared the toy they picked were labeled as "altruistic sharers" and those who shared the opposite toy were labeled "selfish sharers." When researchers compared the two tasks, they found that the "altruistic sharers were really sensitive to the violation of fairness in the food task," according to Sommerville.

So what does this mean for your baby? First, it suggests that babies develop a sense of fairness and altruism even earlier than previously thought -- other studies had placed the development of a sense of fairness at 6 or 7 years. It also means that researchers will continue working on the topic in an effort to figure out if fairness and altruism are inborn or a result of nurturing -- though for right now, Sommerville says she wouldn't be surprised to find out that the infants are developing their behavior based on how fair and generous their own families are.

"It's likely that infants pick up on these norms in a nonverbal way," she said, "by observing how people treat each other."

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