Oberliessen Lina, Kalenscher Tobias
Comparative Psychology, Institute of Experimental Psychology, Heinrich Heine University, Düsseldorf, Germany.
Front Behav Neurosci. 2019 Jun 21;13:133. doi: 10.3389/fnbeh.2019.00133. eCollection 2019.
Research over the last decades has shown that humans and other animals reveal behavioral and emotional responses to unequal reward distributions between themselves and other conspecifics. However, cross-species findings about the mechanisms underlying such inequity aversion are heterogeneous, and there is an ongoing discussion if inequity aversion represents a truly social phenomenon or if it is driven by non-social aspects of the task. There is not even general consensus whether inequity aversion exists in non-human animals at all. In this review article, we discuss variables that were found to affect inequity averse behavior in animals and examine mechanistic and evolutionary theories of inequity aversion. We review a range of moderator variables and focus especially on the comparison of social vs. non-social explanations of inequity aversion. Particular emphasis is placed on the importance of considering the experimental design when interpreting behavior in inequity aversion tasks: the tasks used to probe inequity aversion are often based on impunity-game-like designs in which animals are faced with unfair reward distributions, and they can choose to accept the unfair offer, or reject it, leaving them with no reward. We compare inequity-averse behavior in such impunity-game-like designs with behavior in less common choice-based designs in which animals actively choose between fair and unfair rewards distributions. This review concludes with a discussion of the different mechanistic explanations of inequity aversion, especially in light of the particular features of the different task designs, and we give suggestions on experimental requirements to understand the "true nature" of inequity aversion.
过去几十年的研究表明，人类和其他动物会对自身与其他同种个体之间不平等的奖励分配表现出行为和情绪反应。然而，关于这种不公平厌恶背后机制的跨物种研究结果并不一致，而且对于不公平厌恶是一种真正的社会现象还是由任务的非社会方面所驱动，目前仍在讨论之中。甚至对于非人类动物是否存在不公平厌恶都没有普遍共识。在这篇综述文章中，我们讨论了已发现的会影响动物不公平厌恶行为的变量，并审视了不公平厌恶的机制和进化理论。我们回顾了一系列调节变量，尤其着重于对不公平厌恶的社会解释与非社会解释的比较。在解释不公平厌恶任务中的行为时，特别强调了考虑实验设计的重要性：用于探究不公平厌恶的任务通常基于类似免罚博弈的设计，即动物面临不公平的奖励分配，它们可以选择接受不公平的提议，或者拒绝它，结果是得不到奖励。我们将这种类似免罚博弈设计中的不公平厌恶行为与不太常见的基于选择的设计中的行为进行比较，在基于选择的设计中，动物在公平和不公平的奖励分配之间主动做出选择。这篇综述最后讨论了对不公平厌恶的不同机制解释，特别是鉴于不同任务设计的特殊特征，并且我们给出了关于实验要求的建议，以理解不公平厌恶的“真实本质”。
