ABSTRACT

Portraits of humans favour the left cheek, with emotion thought to drive this posing asymmetry. In primates the emotion-dominant right hemisphere predominantly controls the left hemiface, rendering the left cheek anatomically more expressive than the right. As perceptions of nonhuman primates vary with genetic relatedness, depictions of nonhuman primates should theoretically be influenced by their phylogenetic proximity to humans. The present study thus examined whether humans depict nonhuman primates showing the left cheek, and whether depictions vary with evolutionary distance. Photographs of nonhuman primates were sourced from Instagram’s “Most recent” feed: great apes (#chimpanzee, #bonobo, #gorilla, #orangutan), lesser apes (#gibbon), Old World monkeys (#baboon, #macaque, #proboscismonkey), New World monkeys (#spidermonkey, #marmosetmonkey, #capuchin), and prosimians (#lemur, #slowloris, #tarsier). The first 500 single-subject images for each hashtag (except #slowloris for which 318 images were available) were coded for pose orientation (left, right) and portrait type (head/torso, full body). As anticipated, there was a left cheek bias for great apes but no bias for more distantly related primates. These data thus suggest that depictions of nonhuman primates are implicitly influenced by phylogenetic proximity: the more closely related the primate, the more likely we are to depict them as we do ourselves, showing the left cheek.

摘要

人像偏爱左脸颊，情感被认为是造成这种姿势不对称的原因。在灵长类动物中，以情感为主的右半球主要控制着左半脸，从而在解剖学上使左脸颊比右脸更具表现力。由于对非人类灵长类动物的认识随遗传相关性而变化，因此从理论上讲，非人类灵长类动物的描述应受其与人类的亲缘关系的影响。因此，本研究检查了人类是否描绘了非人类的灵长类动物，它们显示了左脸颊，以及描绘内容是否随着进化距离而变化。非人类灵长类动物的照片来自Instagram的“最新”提要：大猿猴（＃黑猩猩，＃bonobo，＃大猩猩，＃猩猩），小猿猴（＃长臂猿），旧世界猴子（＃狒狒，＃猕猴，＃proboscismonkey） ，新世界猴子（＃spidermonkey，＃marmosetmonkey，#capuchin）和prosimians（＃lemur，＃slowloris，＃tarsier）。每个主题标签的前500个单主题图像（除了#slowloris可获得318张图像）均已编码为姿势方向（左，右）和肖像类型（头部/躯干，全身）。正如预期的那样，大猿猴的脸颊偏左，而与远亲相关的灵长类动物则没有偏斜。因此，这些数据表明，非人类灵长类动物的描写受到系统发育接近性的隐式影响：与灵长类动物关系越密切，我们越有可能像我们自己一样描绘它们，并显示左脸颊。正如预期的那样，大猿猴的脸颊偏左，而与远亲相关的灵长类动物则没有偏斜。因此，这些数据表明，非人类灵长类动物的描写受到系统发育接近性的隐式影响：与灵长类动物关系越密切，我们越有可能像我们自己一样描绘它们，并显示左脸颊。正如预期的那样，大猿猴的脸颊偏左，而与远亲相关的灵长类动物则没有偏斜。因此，这些数据表明，非人类灵长类动物的描写受到系统发育接近性的隐式影响：与灵长类动物关系越密切，我们越有可能像我们自己一样描绘它们，并显示左脸颊。