Dr. Yanjie Su’s laboratory from School of Psychological and Cognitive Sciences of Peking University published the paper “ ‘Favoring my playmate seems fair’: Inhibitory control and theory of mind in preschoolers’ self-disadvantaging behaviors” on Journal of Experimental Child Psychology in August, 2019. The study investigated the relationship between preschoolers’ cognitive abilities and their fairness-related allocation behaviors in a dilemma of equity–efficiency conflict. Dongjie Xie, the Ph.D. student from School of Psychological and Cognitive Sciences of Peking University, was the first author of this paper, and Yanjie Su, the professor from School of Psychological and Cognitive Sciences of Peking University, was the corresponding author of this paper. The work was funded by National Natural Science Foundation of China.

Humans have regarded fairness as central to morality and social norms. Resource allocation is a crucial context to study humans’ understanding of fairness and its ontogeny, and equality (everyone receives the same) is a simple rule of fairness. In real-life situations, however, resources cannot always be allocated equitably and individuals may encounter situations where equity is in conflict with efficiency. An example features a lab manager allocating several old computers and a powerful new computer to graduate students. Any efficient plan would make use of the new computer, but doing so would sacrifice equity because the new one would give its user an advantage over other students.

Previous studies found that adults and children as first-parties tended to give more to other, resulting in disadvantageous inequity but promoting efficient resource allocation, whereas they were more likely to make an equitable allocation and waste some as third-parties. This phenomenon was named as the self-disadvantaging effect. But how this effect develops is unknown. The study included two experiments to examine the potential cognitive mechanisms of it.

In Experiment 1, 4- to 6-year-olds (N = 99) decided how to allocate five reward bells. In the first-party condition, preschoolers were asked to choose among giving more to self (self-advantageous inequity), wasting one bell (equity), or giving more to other (self-disadvantageous inequity); in the third-party condition, they chose either to allocate the extra bell to one of two equally deserving recipients or to waste it. Results showed that, compared with the pattern of decision in the third-party condition, preschoolers in the first-party condition were more likely to give the extra bell to other (self-disadvantaging behaviors) and that age, inhibitory control (IC), and theory of mind were positively correlated with their self-disadvantaging choices, but only IC mediated the relationship between age and self-disadvantaging behaviors. Experiment 2 (N = 41) showed that IC still predicted preschoolers’ self-disadvantaging behaviors when they could choose only between equity and disadvantageous inequity. These results suggested that IC played a critical role in the implementation of self-disadvantaging behaviors when this required the control over selfishness and envy.

Xie, D., Pei, M., & Su, Y. (2019). "Favoring my playmate seems fair": Inhibitory control and theory of mind in preschoolers' self-disadvantaging behaviors. Journal of Experimental Child Psychology, 184, 158-173.