Primate Research Institute, Kyoto University, Inuyama, Japan.
Japan Society for the Promotion of Science, Tokyo, Japan.
Dev Sci. 2020 Nov;23(6):e12975. doi: 10.1111/desc.12975. Epub 2020 May 18.
Human adults are better at recognizing upright bodies than inverted bodies. This inversion effect is also found for objects with which they have expertise, which is called the expert effect. This study aims to investigate its evolutionary and developmental aspects by testing humans' closest relatives, chimpanzees, and preschool children. Chimpanzees show the inversion effect to chimpanzee bodies, but it is not clear how they perceive other species' bodies. We tested seven chimpanzees in matching-to-sample tasks on touch screens using upright and inverted stimuli, and examined their accuracy and response time. In a previous study, they did not show the inversion effect for bipedal humans in unfamiliar postures, but here in this study they showed it to bipedal humans with familiar postures or crawling postures. This suggests the existence of the expert effect in non-human primates, and that visual or embodied experience is needed to invoke it. It is also supported by the inversion effect they exhibit for horses who share quadrupedal postures, but which they have never seen. Additionally, for conspecifics, the inversion effect was shown regardless of the postures. We tested 33 preschool children using a similar method. They showed the inversion effect to human bodies, but not houses, suggesting the configural processing for bodies, which is found to be stable at the preschool stage. They also showed the inversion effect for chimpanzees and horses, indicating the important role of experience in shaping the ways of object processing.
人类成年人比识别倒置的身体更擅长识别直立的身体。这种倒置效应也存在于他们具有专业知识的物体中，这被称为专家效应。本研究旨在通过测试人类最亲近的亲属——黑猩猩和学龄前儿童，来研究其进化和发展方面。黑猩猩对黑猩猩的身体表现出了倒置效应，但不清楚它们如何感知其他物种的身体。我们在触摸屏上使用直立和倒置的刺激物，在匹配样本任务中对七只黑猩猩进行了测试，并检查了它们的准确性和反应时间。在之前的一项研究中，它们没有表现出对陌生姿势的双足人类的倒置效应，但在本研究中，它们对熟悉姿势或爬行姿势的双足人类表现出了这种效应。这表明非人类灵长类动物存在专家效应，并且需要视觉或体现经验来引发这种效应。这也得到了它们对具有四足姿势但从未见过的马所表现出的倒置效应的支持。此外，对于同类，无论姿势如何，都表现出了倒置效应。我们使用类似的方法测试了 33 名学龄前儿童。他们对人体表现出了倒置效应，但对房屋没有表现出倒置效应，这表明了对身体的模式处理，这种处理在学龄前阶段是稳定的。他们还对黑猩猩和马表现出了倒置效应，这表明经验在塑造物体处理方式方面起着重要作用。
