Doctoral Dissertation Improvement: Application of the Facial Action Coding System to Nonhuman Anthropoids

从面部表情推断他人的意图和情绪是类人猿灵长类动物（猴子、猿和人类）社会互动的一个组成部分。然而，导致面部表情精细化的适应性因素尚不清楚。这是由于缺乏定量的比较数据，而这是确定共同适应趋势所必需的。与面部表情直接相关的一个比较变量是面部活动性，或者一个人能够进行的不同面部动作的数量。本研究的目的是建立一种基于面部动作编码系统（FACS）的非人类类人猿面部活动量化的新观察方法。FACS是当今心理学中使用的主要方法，用于描述人类面部显示的组成元素，涉及其肌肉基础。该方法区分“动作单元”，对应于面部表情的一个或多个肌肉的活动。标准化标准用于从面部动作的视频记录中对动作单元的存在进行评分。由于类人猿面部肌肉来源于相同的发育前体，并且人类在这一肌肉群中表现出最大的分化，因此FACS代表了类人猿可能运动的整个范围。因此，面部活动性可以被量化为个体表现出的不同动作单元的数量。FACS将用于估计来自北美动物园的15种类人猿的75个个体的面部活动能力。将使用数字摄像机获得焦点动物样本。每个样本将被记录10分钟，动作单元将通过慢动作和定格回放进行评分。焦点采样将继续对每个个体进行，直到先前未观察到的动作单元的数量达到渐近线为零。由此产生的数据集将有助于测试面部表情进化的适应性假设，为类人猿行为和交流的研究开辟新的途径。这项研究更广泛的影响包括创建一个在线视频数据库和类人猿面部行为的静态帧例子。这一资源将有助于教育公众关于人类和非人类灵长类动物情感表达之间的联系，将人类社会行为的这一重要方面牢固地置于进化的背景下。

Inferring the intentions and emotions of others from facial expressions is an integral part of social interaction in anthropoid primates (monkeys, apes and humans). However, the adaptive factors responsible for the elaboration of facial expression are unknown. This is due to a lack of quantitative comparative data, which is necessary for the identification of shared adaptive trends. A comparative variable of direct relevance to facial expression is facial mobility, or the number of different facial movements an individual is capable of performing. The goal of this study is to develop a new observational method for quantifying facial mobility in nonhuman anthropoids based on the Facial Action Coding System (FACS). FACS is the main method used in psychology today to describe the constituent elements of human facial displays with regard to their muscular basis. The method differentiates "action units" that correspond to the activity of one or more muscles of facial expression. Standardized criteria are used to score the presence of action units from video recordings of facial movements. Since anthropoid facial muscles derive from the same developmental precursors and humans exhibit the greatest differentiation of this muscle group, FACS represents the entire range of possible movements for anthropoids. Thus, facial mobility may be quantified for an individual as the number of different action units exhibited. FACS will be used to estimate facial mobility for up to 75 individuals representing 15 species of anthropoids from zoos in North America. Focal animal samples will be attained using a digital video camcorder. Individuals will be recorded for 10 minutes per sample and action units will be scored from slow-motion and stop-frame playback. Focal sampling will continue for each individual until the number of previously unobserved action units reaches an asymptote of zero. The resulting dataset will facilitate the testing of adaptive hypotheses for the evolution of facial expression, opening new avenues of research into anthropoid behavior and communication. The broader impacts of this study include the creation of an online database of video and still-frame examples of anthropoid facial behaviors. This resource will help educate the public about the links between human and nonhuman primate emotional expression, firmly placing this important aspect of human social behavior within the context of evolution.