Children reject inequity out of spite

When confronted with inequality, human children and adults sacrifice personal gain to reduce the pay-offs of other individuals, exhibiting apparently spiteful motivations. By contrast, sacrifice of personal gain by non-human animals is often interpreted as frustration. Spite may thus be a uniquely human motivator. However, to date, no empirical study has demonstrated that psychological spite actually drives human behaviour, leaving the motivation for inequity aversion unclear. Here, we ask whether 4- to 9-year-old children and adults reject disadvantageous inequity (less for self, more for peer) out of spite or frustration. We show that children, but not adults, are more likely to reject disadvantageous allocations when doing so deprives their peer of a better reward (spite) than when their peer has already received the better reward (frustration). Spiteful motivations are thus present early in childhood and may be a species-specific component of humans' developing cooperative and competitive behaviour.

当遭遇不公平状况时，人类儿童与成人会牺牲自身收益，以降低他人的所得回报，展现出典型的恶意动机（spiteful motivations）。与之形成对比的是，非人类动物的收益牺牲行为通常被解读为受挫情绪的体现。由此可见，恶意动机或许是人类独有的行为动因。然而迄今为止，尚无实证研究证明心理层面的恶意确实会驱动人类行为，这使得不公平厌恶（inequity aversion）背后的动因始终不明。本研究旨在探究：4至9岁儿童与成人是否会出于恶意或受挫情绪，拒绝接受对自身不利的不公平分配（即自身所得更少、同伴所得更多的分配方案）。研究结果显示：当拒绝分配会剥夺同伴的更高奖励（对应恶意动机场景）时，儿童（而非成人）更倾向于拒绝该不利分配；而当同伴已获得更高奖励（对应受挫情绪场景）时，则无此倾向。由此可见，恶意动机早在儿童时期便已出现，或许是人类在合作与竞争行为发展过程中所特有的组成部分。