Medial frontal negativity (MFN) is an event-related potential thought to originate in the anterior cingulate cortex. It is evoked by outcomes being worse than expected, such as when presented with unfair economic proposals during the Ultimatum Game (UG). This could mean the MFN indexes a social-emotional response, as commonly suggested in accounts that relate it to a violation of a social norm of fairness. To examine the link between MFN and norm violation, we designed an EEG experiment with participants acting as representatives in an UG. Participants responded either as themselves, or as representatives of two charities. Of these, a norm-compatible charity conformed to the participant's values, while the norm-incompatible charity contrasted to them. The behavioral results showed that norm-incompatible representation reversed behavior, with almost all fair offers being declined. The MFN, however, was unaffected by the norm representation, with unfair offers consistently evoking MFNs across conditions. We furthermore replicated the curious finding that unexpectedly generous offers evoke as much MFN as unfair offers. Thus, the MFN is not nearly as sensitive to higher-order social-emotional processes as commonly assumed. Instead, the perceived inequality that drives the MFN likely reflects a rational, probabilistic process.

中文翻译：

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我给您一个您可以拒绝的报价：最惠国待遇在社会上有多敏感？

内侧额叶负性（MFN）是与事件相关的潜在电位，被认为起源于前扣带回皮层。结果比预期的要差，例如在最后通Game博弈（UG）中提出不公平的经济建议时，就会引起这种情况。这可能意味着，最惠国待遇将一种社会情感反应纳入索引，这在与违背社会公平规范的行为相关的叙述中通常会提出。为了研究最惠国待遇与违反规范之间的联系，我们设计了一项以参与者作为UG代表的EEG实验。参与者以自己或两个慈善机构的代表的身份回应。其中，与规范不相容的慈善机构符合参与者的价值观，而与规范不相容的慈善机构则与之形成对比。行为结果表明，规范不兼容表示会逆转行为，几乎所有公平的报价都被拒绝了。但是，最惠国待遇不受规范代表的影响，不公平的报价始终会引起跨条件的最惠国待遇。我们进一步复制了一个奇怪的发现，即出乎意料的慷慨要约会产生与不公平要约一样多的最惠国待遇。因此，最惠国待遇不像通常假定的那样对高阶社会情感过程敏感。相反，驱动最惠国待遇的感知不平等可能反映了一个理性的概率过程。最惠国待遇对高阶社会情感过程的敏感度不如通常假定的那么敏感。相反，驱动最惠国待遇的感知不平等可能反映了一个理性的概率过程。最惠国待遇对高阶社会情感过程的敏感度不如通常假定的那么敏感。取而代之的是，导致最惠国待遇的不平等现象可能反映了一个理性的概率过程。