In the recent review by Waller et al. (2020) the authors discuss how the Facial Action Coding System (FACS) can be used to study the evolution of facial behaviors. This is a timely and thought-provoking review which highlights the numerous ways in which FACS could be used to compare the mechanisms responsible for the production of facial behaviors across species. We propose that FACS could also be used to study the recognition of facial behaviors in nonhuman subjects where one of the key challenges is finding suitable stimuli that convey different emotions. By using FACS-rated images in awake neuroimaging experiments, researchers could accurately identify the brain mechanisms responsible for recognizing expressions across mammalian species. This approach would reveal neural homologs and deepen our understanding of how nonverbal social communication has evolved.

在最近的Waller等人的评论中。（2020）作者讨论了如何使用面部动作编码系统（FACS）来研究面部行为的演变。这是一项及时而发人深省的评论，强调了FACS可以用来比较负责跨物种产生面部行为的机制的多种方式。我们建议FACS也可以用于研究识别非人类受试者的面部行为研究，其中的主要挑战之一就是寻找合适的刺激物来传达不同的情感。通过在清醒的神经影像实验中使用FACS评定的图像，研究人员可以准确地识别负责识别哺乳动物物种表达的大脑机制。这种方法将揭示神经同源物，并加深我们对非语言社交传播如何演变的理解。