translation.en: In a recent mimicking study at the University of Clermont-Ferrand in France, subjects were asked to determine whether a smile was real or fake while holding a pencil in their mouth to repress smiling muscles.
translation.zh: 近期的一项模拟研究 要求研究对象 通过微笑肌肉 把一支铅笔含在嘴上 以此判断微笑的真假