Face recognition is important for primate social cognition, enabling rapid discrimination between faces and objects. In humans, face recognition is characterized by certain cognitive specializations such as face-specific sensitivity to upright faces. The face inversion effect reflects the disproportionate inversion cost (i.e., poorer recognition of inverted compared to upright stimuli) for faces compared to non-face objects. Numerous studies have evaluated the face inversion effect in various nonhuman primates, but the findings are highly variable and mixed, especially in monkeys. To address this inconsistency, the current study employed a multilevel, phylogenetic meta-analysis on 52 effect sizes across 16 studies to quantify the magnitude of the face inversion effect in nonhuman primates. Overall, the difference in inversion costs for faces compared to nonface stimuli was small but not statistically significant (b = 0.31, se = 0.16, 95% CI [− 0.01, 0.62], p = 0.06). Additionally, this did not systematically vary between the family of species (chimpanzee or monkey) or type of face stimuli (conspecific or heterospecific). Ultimately, it cannot be concluded that the face inversion effect is a reliable phenomenon in either chimpanzees or monkeys, suggesting that nonhuman primates may not use similar face-specific processing strategies as humans.

中文翻译：

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量化非人类灵长类动物的面部倒立效果：系统进化荟萃分析

人脸识别对于灵长类动物的社会认知非常重要，它可以快速区分人脸和物体。在人类中，面部识别的特征在于某些认知专长，例如对直立面部的面部特定敏感性。与非面部对象相比，面部倒立效果反映了面部不成比例的倒置成本（即，与直立刺激相比，对倒立的识别较差）。许多研究已经评估了各种非人类灵长类动物的面部倒置效果，但是这些发现是高度可变且混杂的，尤其是在猴子中。为了解决这一矛盾，当前的研究对16个研究中的52种效应量进行了多层次的系统进化荟萃分析，以量化非人类灵长类动物面部反转效应的强度。总体，b  = 0.31，se = 0.16，95％CI [-0.01，0.62]，p  = 0.06）。此外，这在物种家族（黑猩猩或​​猴子）或面部刺激类型（同种或异种）之间没有系统地变化。最终，不能得出结论，无论是黑猩猩还是猴子，面部倒置都是可靠的现象，这表明非人类的灵长类动物可能不会使用与人类相似的特定于面部的加工策略。