Young children will pay a price to be better off relative to others, according to new research by Yale psychologists published in the February 2014 edition of the journal Cognition.

The group of researchers demonstrated that children would pay in order to ensure that their welfare was equal to or greater than that of another child. Though all ages studied were willing to sacrifice material gain to achieve equality, the desire to place other children in a lesser position diminished significantly with age. Such findings may help illuminate the development of social comparison and concepts of inequality in children, said study author Mark Sheskin, a former Yale graduate student in psychology who is now a postdoctoral researcher at Ecole Normale Supérieure in Paris.

“I think that the new most exciting thing in the study is that the younger children, so ages five and six, will spitefully take a cost in order to be at a relative advantage,” Sheskin said. “That might clarify some of what might be going on with the early emergence of fairness concerns.”

In the study, each child was told that they had to decide how valuable tokens would be distributed between themselves and another child who would arrive later in the day. The researchers found that children would accept a cost in order to be better off relative to another child in the study. Many children decided to receive fewer tokens total if it meant the other child received less than them. For example, if given the choice between a situation where the child and their counterpart each receive eight tokens and a situation where the child receives seven tokens and the counterpart receives none, younger children opted for the latter.

While the study also showed that children would take a cost to achieve equality, the result that they would also take a cost to achieve a relative advantage demonstrates that young children desire to be better off relative to others and not in an absolute sense, Frans de Waal, a professor of primate behavior at Emory University, explained in an email.

“We need this sort of study to peel away the layers of tendencies underlying the human’s sense of fairness, which [have] puzzled philosophers and scientists for so long,” he said.

This advantage-seeking behavior was most pronounced at the youngest age and declined as age increased: while 37 percent of the youngest — five and six years old — selected the fair option over the one that gave them the most relative advantage, 71.6 percent of the older children — nine and 10 years old — chose the fair option.

The mechanism of this change, however, remains unknown.

“I’m kind of wary of explanations that claim something about maturation,” said Peter Blake, a professor of psychology at Boston University. “Across a number of studies, we’ve seen children’s equity aversion kind of shift from older or younger, so situation and context seem to be important variables, and I think cultural norms are going to be important.”

Blake praised the study for using an objective measure of equality — the coins — which allowed them to pinpoint the advantage-seeking behavior of the children. Blake added that the results could only be explained by children seeking to create a relative advantage for themselves.

Sheskin said he believes this study fits into a larger trend in the field because it moves beyond identifying concepts of fairness in humans and primates towards developing a more nuanced understanding of these phenomena.

In addition to Sheskin, the study was authored by Yale psychologists Paul Bloom and Karen Wynn.