People hate being deceived. However, what would it be if lies come from in-group members compared with that from out-group members? In the current Electroencephalography (EEG) study, we recruited thirty-six participants to play a modified estimator and advisor game to investigate the mental and neural processes to lies and truth conveyed by in-group and out-group members. At the behavioral level, lies are less morally acceptable, arose less positive emotion, and made participants distribute less money to the advisor in a dictator game. Meanwhile, participants liked the in-group university more than the out-group university and they thought they were more similar to in-group members than to out-group members. However, there were no significant interactions of group type (i.e., in-group and out-group) and message type (i.e., lies and truth) in the aforementioned behavioral assessments. At the neural level, significant interaction effects were found in the parietal N1 and P3 amplitude. More importantly, no significant N1 and P3 amplitude differences between in-group lies and truth were found, while outgroup lies elicited larger P3 amplitude than outgroup truth and out-group truth elicited larger N1 amplitude than outgroup lies. What's more, P3 amplitude differences between lies vs. truth positively correlated with fairness scores only in the in-group condition but not in the out-group condition. Current study showed that the P3 component was sensitive in capturing subtle differences when participants were processing different types of lies and truth that could not be captured by behavioral measurements. Besides, the fairness trait modulated the in-group bias related P3 patterns. The current study provides insight into the neurobiological mechanism underlying the mental process of in-group and out-group lies and truth, and suggests individuals' tendency of general in-group favoritism and out-group discrimination toward moral behaviors.

中文翻译：

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群体内“偏爱”和群体外“歧视”对道德行为的神经反应。

人们讨厌被欺骗。但是，如果谎言来自团体内成员，而谎言来自团体外成员，那会是什么呢？在当前的脑电图（EEG）研究中，我们招募了36名参与者参加改良的估算器和顾问游戏，以研究小组内和小组外成员传达的关于谎言和真相的心理和神经过程。在行为层面上，谎言在道德上不那么容易接受，产生的积极情绪也更少，并且使得参与者在独裁者游戏中将更少的钱分配给顾问。同时，参与者更喜欢组内大学而不是组外大学，并且他们认为他们与组内成员相似而不是组外成员。但是，组类型（即组内和组外）和消息类型（即，谎言和真相）。在神经水平上，在顶叶N1和P3振幅中发现了显着的相互作用。更重要的是，没有发现群体内谎言和真相之间的N1和P3幅度差异显着，而群体外谎言所引起的P3幅度大于群体真理，而群体外真相引起的N1和N3幅度大于群体谎言。更重要的是，谎言与真相之间的P3幅度差异仅在组内条件下与公平得分正相关，而在组外条件下则没有。当前的研究表明，当参与者处理行为测量无法捕获的不同类型的谎言和真相时，P3成分对于捕获细微差异非常敏感。除了，公平性状调节了与组内偏倚相关的P3模式。当前的研究提供了对群体内和群体外谎言和真理心理过程的神经生物学机制的洞察力，并提出了个体普遍的群体内偏爱倾向和群体间对道德行为的歧视倾向。