A new study conducted this year by Yale psychology professor Kristina Olson and psychology graduate student Alexander Shaw GRD ’14 has found that children develop an understanding of fairness early in life, but this understanding manifests itself in behavior more frequently when people are looking.

The study, entitled “Children develop a veil of fairness,” appeared on “60 Minutes” on Nov. 18 and is currently in publication. In the experiment, an adult gave a child two chocolate bars and put aside two others for someone else. The child, who was on average around 7 years old, was then asked to choose between keeping a fifth chocolate bar, giving it to the other child or throwing it away. In the alternate trial, the adult left the experiment room after placing only one chocolate bar into the subject’s envelope, and a new adult arrived briefly to add the second bar to the envelope. When the first adult returned, the child again had to decide what to do with the fifth bar, knowing that the first experimenter was unaware a second bar had already been placed in the envelope. In the first trial, most children insisted that the fifth bar be thrown away. In the second trial, however, many more responded that they should receive the fifth bar.

Olson suspects this phenomenon occurs because competing interests are at work.

“Children have two real tendencies — a tendency to want things to be fair between others and a tendency to want to have more for themselves,” she said. “Different situations such as competition or wanting to look good to an adult might make children display one of these tendencies more than another.”

The point of the “sneaky studies” was to demonstrate that these behaviors were essentially adaptive, Olson said. What appears as a child’s desire to be fair may actually only be a desire to appear fair in an effort to get more for oneself, she added.

Shaw, who led the research and is conducting follow-ups, said the study changes what scientists know about the development of the understanding of fairness in children.

“It is surprising that children care about how they appear at such a young age,” Shaw said. “Children get upset when they see that others have more than they do beginning at the age of 3. Many have thought that by the time that children are between 6 and 8 years old, they begin to care about fairness and being fair. But it is really more about appearing fair.”

Shaw added that children understand others will be upset with them when they have more than someone else does. Their desire to seem fair is a “cost” they are willing to pay instead of receiving additional resources, which is not worth the loss in social standing, he said.

While it is unlikely that children think all these social costs through, Shaw suspects humans are empowered with “some kind of system” for acquiring an understanding of the social rules that should not be broken.

Psychology professor Paul Bloom, who was not involved in the study, said Shaw and Olson have done “great work.” In the “60 Minutes” piece, he called the children’s demonstrated desire to throw chocolate bars away for the sake of fairness “a gorgeous finding.”

Shaw and Olson’s study was conducted with the help of researchers from Harvard University, the University of Copenhagen and the Max Planck Institute of Economics in Germany.