Awareness of death has been shown to influence human cognition and behavior. Yet, how mortality threat (MT) impacts our daily social behavior remains elusive. To address this issue, we developed a dyadic experimental model and recruited 86 adults (43 dyads) to complete two computer-based tasks (i.e. competitive and cooperative button-pressing). We manipulated dyads’ awareness of death [MT vs neutral control (NC)] and simultaneously measured their neurophysiological activity using electroencephalography during the task. Several fundamental observations were made. First, the MT group showed significantly attenuated competition and slightly promoted cooperation. Second, compared to NC, MT significantly decreased gamma-band inter-brain synchronization (IBS) in the competitive context, which was associated with increased subjective fear of death within dyads. Notably, those effects were context-specific: we did not observe comparable results in the cooperative context. Finally, a machine-learning approach was successfully used to discriminate between the MT and NC groups based on accumulated IBS. Together, these findings indicate that MT to some extent mitigates interpersonal competition, and such mitigation might be associated with changes in gamma-band IBS.

中文翻译：

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死亡威胁减轻人际竞争：基于脑电图的超扫描研究

死亡意识已被证明会影响人类的认知和行为。然而，死亡威胁 (MT) 如何影响我们的日常社会行为仍然难以捉摸。为了解决这个问题，我们开发了一个二元实验模型，并招募了 86 名成年人（43 名二元组）来完成两项基于计算机的任务（即竞争性和合作性按键）。我们操纵了 dyads 的死亡意识 [MT 与中性控制 (NC)]，并在任务期间同时使用脑电图测量了他们的神经生理活动。进行了几项基本观察。首先，MT组竞争明显减弱，合作略有促进。其次，与 NC 相比，MT 在竞争环境中显着降低了 gamma 波段脑间同步 (IBS)，这与二元组中对死亡的主观恐惧增加有关。值得注意的是，这些影响是特定于环境的：我们没有在合作环境中观察到可比的结果。最后，机器学习方法成功地用于根据累积的 IBS 区分 MT 和 NC 组。总之，这些发现表明 MT 在一定程度上缓解了人际竞争，这种缓解可能与伽马波段 IBS 的变化有关。