Cheater detection, which is a prerequisite for the evolution of social cooperation, has been successfully simulated in laboratory settings. However, the process has not been perfect because the detection rate has usually been just above chance. The present study investigated the role of lateral posing biases and emotional expressions in displaying trustworthiness, which plays a crucial role in cheater detection. Participants (N = 30 and 28 in Experiments 1 and 2, respectively) observed facial photographs of cheaters and cooperators in an economic game and evaluated their facial expressions in terms of emotional valence and arousal. The models in the photographs had turned their left or right cheek to the camera to display their trustworthiness in the economic game. The results indicated that cheaters showing their left cheek were rated as more emotionally positive than cheaters showing their right cheek. This lateral difference was not observed for cooperators. A left cheek advantage in emotional arousal was found for both cheaters and cooperators. These results suggest that cheaters use a fake smile on the emotional side of their face (i.e., the left) to conceal their uncooperative attitude.

骗子检测是社会合作发展的前提，已经在实验室环境中成功进行了模拟。但是，此过程并不完美，因为检测率通常刚好高于偶然性。本研究调查了横向摆姿势的偏见和情绪表达在显示可信度中的作用，这在作弊者检测中起着至关重要的作用。参加人数 在实验1和2中分别为30和28）在经济游戏中观察了作弊者和合作者的面部照片，并根据情感价和唤醒来评估他们的面部表情。照片中的模型将他们的左右脸颊转向相机，以显示其在经济游戏中的可信度。结果表明，表现出左脸颊的作弊者比表现出右脸颊的作弊者在情感上更积极。合作者没有观察到这种横向差异。欺骗者和合作者在情感唤醒中都具有左颊优势。这些结果表明，作弊者在其面部情感一侧（即左侧）使用假笑来掩饰其不合作的态度。