Humans resist unequal distributions of goods in their social interactions, even if it requires foregoing personal gains. Functional neuroimaging studies implicate the insula in this aversion to social inequity and in fairness-related decisions, but a causal contribution has not yet been established. We compared the responses of 30 patients with lesions to the insula on a multiple-trial version of the one-shot Ultimatum Game, a neuroeconomic social exchange paradigm where a sum of money is split between two players, to those of 30 matched patients with brain injuries sparing the insula. Insula lesion patients accepted offers of an unequal disadvantageous split significantly more often than comparison lesion patients. Computational modeling confirmed that this difference in choice behavior was due to decreased aversion to disadvantageous inequity following insula damage, rather than due to increased decision noise or non-consideration of inequity. Our results provide novel evidence that the insula is causally involved in aversion to inequity and in value-based choices in the context of social interactions.

中文翻译：

---

岛叶在厌恶社会不平等中的因果作用的损伤证据


人类在社会交往中抵制商品的不平等分配，即使这需要放弃个人利益。功能性神经影像学研究表明，岛叶与这种对社会不平等的厌恶和与公平相关的决策有关，但其因果关系尚未确定。我们将 30 名脑岛病变患者在一次性最后通牒游戏（一种神经经济社会交换范式，其中一笔钱在两名玩家之间分配）的多次试验版本中的反应与 30 名匹配的脑岛病变患者的反应进行了比较。不影响岛叶的损伤。岛叶病变患者比对照病变患者更频繁地接受不平等不利分割的提议。计算模型证实，选择行为的这种差异是由于岛叶损伤后对不利的不平等的厌恶减少，而不是由于决策噪音增加或不考虑不平等。我们的研究结果提供了新的证据，表明岛叶与社会互动背景下对不平等的厌恶和基于价值的选择有因果关系。