THURSDAY, Nov. 19, 2015 (HealthDay News) -- Everyone is apparently born with the ability to detect unfair treatment, but kids don't naturally sense when someone else is getting a raw deal at their expense, a new globe-spanning study has found.
The researchers contend that it's the culture that kids are raised in that lets them recognize when they're being treated better than another person -- and to act accordingly.
In a series of tasks involving candy, hundreds of young kids from seven countries around the world -- the United States, Canada, India, Mexico, Peru, Senegal and Uganda -- innately grasped the unfairness of being given less candy than another child.
"I think it's evolutionary," said Dr. Matthew Lorber, acting director of child and adolescent psychiatry at Lenox Hill Hospital in New York City, who was not involved in the research. "There's something inbred in us for survival, that when we're very young we make sure we stand up for ourselves and are taken care of."
But only older kids from the United States, Canada and Uganda were able to sense unfairness -- and act on it -- when given more candy than another child, the researchers found.
"This suggested to us that this form of unfairness -- that is, a negative reaction to getting more than others -- may be importantly influenced by culture," said study co-author Katherine McAuliffe, a postdoctoral fellow at Yale University's Social Cognitive Development Lab in New Haven, Conn.
In the study, published online Nov. 18 in the journal Nature, one child sat across from another and was given control of two handles attached to two trays carrying candies.
Researchers varied the amounts of candies on each tray, McAuliffe said. Sometimes the amounts were equal, sometimes the kids controlling the handle got more candy, and sometimes they got less.
"After the [kids] saw the allocations, they were faced with a choice. They could either accept the allocation, in which case both children got treats, or they could reject the allocation, in which case neither child got treats," she said. "This is important because here the fairness of rejecting inequality both goes against the child's own self-interest and is not really nice to the partner."
The study included 866 kids, aged 4 to 15, across the world. Nearly all of them, from a fairly young age, were willing to dump the trays if they got less candy than their counterpart, the investigators found.
"This suggested to us that this form of unfairness -- that is, a negative reaction to getting less than others -- may be a human universal," McAuliffe said. "There seems to be a basic human response to getting less than someone else."
When the tables were turned, however, kids in less-developed countries generally were fine with accepting a deal where they got more candy than their partner.
Canadian and U.S. kids did have a problem with that, though, and many chose to dump the trays rather than have their partner treated unfairly.
"What we think is happening in the U.S. and Canada is that equality norms are often emphasized for children in Western societies," McAuliffe said. "It seems likely children in those two cultures are aware of those norms and are adhering to those norms."
Ugandan kids also were more likely to dump the trays when their partner was treated unfairly. This could be due to the Ugandan school system, in which Western teachers are invited to teach classes and plan curriculum, McAuliffe speculated.
McAuliffe said she would expect the same response in socialist countries as in the Western democracies, since both societies promote equality as part of their culture.
In follow-up studies, the researchers plan to return to the countries and track the cultural norms to which children are exposed, she said.
Lorber said that he found it fascinating that, in America, the nation's sense of fairness seems to win out over any greed promoted by the nation's economic system.
"American culture is very big into fairness, and into taking care of each other, which is very interesting considering that we have a capitalistic society," he said. "Take care of your friends. Take care of your peers. The right thing to do is to make sure everybody has a fair opportunity and gets their share."
For more on childhood social and emotional development, visit the Urban Child Institute.