Agung Nugroho Dwi Atmoko, Sajuthi Dondin, Supraptini Mansjoer Sri, Iskandar Entang, Shalahudin Darusman Huda
Primatology major, Graduate School Program, IPB University-Indonesia, Bogor City, Indonesia.
Primate Research Center, Institute of Research and Community Service (LPPM), IPB University-Indonesia, Bogor-Indonesia.
Commun Integr Biol. 2022 May 10;15(1):137-149. doi: 10.1080/19420889.2022.2070902. eCollection 2022.
The current study was designed to predict why human primates often behave unfairly (equity aversion) by not exhibiting equity preference (the ability to equally distribute outcomes 1:1 among participants). Parallel to humans, besides inequity aversion, lab monkeys such as kin of long-tailed macaques also demonstrate equity aversion depending on their preference for the outcome (food) type. During the pre-experiment phase, a food-preference test was conducted to determine the most preferred income per individual monkey. Red grapes were the most preferred outcome (100%) when compared to vanilla wafers (0%). The first set of experiments used a 1:1 ratio (equity condition) of grape distribution among six kin-pairs of female long-tailed macaques, and we compared their aversion (Av) versus acceptance (Ac). In the second experiment, we assessed the response to the 0:2 and 1:3 ratio distribution of grapes (inequity condition). A total of 60 trials were conducted for each condition with N = 6 pairs. Our results show aversion to the inequity conditions (1:3 ratios) in long-tailed macaques was not significantly different from aversion to the equity conditions (1:1 ratios). We suggest that the aversion observed in this species was associated with the degree of preference for the outcome (food type) offered rather than the distribution ratio. The subjective preferences for outcome types could bring this species into irrationality; they failed to share foods with an equal ratio of 1:1.
当前的研究旨在预测人类灵长类动物为何常常表现出不公平行为（公平厌恶），即不表现出公平偏好（在参与者之间以1:1的比例平等分配结果的能力）。与人类相似，除了不公平厌恶外，诸如长尾猕猴亲属等实验室猴子也会根据它们对结果（食物）类型的偏好表现出公平厌恶。在实验前阶段，进行了一项食物偏好测试，以确定每只猴子最喜欢的收入。与香草威化饼干（0%）相比，红葡萄是最受欢迎的结果（100%）。第一组实验采用了1:1的比例（公平条件）在六对雌性长尾猕猴亲属中分配葡萄，我们比较了它们的厌恶（Av）与接受（Ac）情况。在第二个实验中，我们评估了对0:2和1:3比例的葡萄分配（不公平条件）的反应。每个条件下总共进行了60次试验，N = 6对。我们的结果表明，长尾猕猴对不公平条件（1:3比例）的厌恶与对公平条件（1:1比例）的厌恶没有显著差异。我们认为，在这个物种中观察到的厌恶与所提供结果（食物类型）的偏好程度有关，而不是分配比例。对结果类型的主观偏好可能会使这个物种变得不理性；它们没有以1:1的平等比例分享食物。
