How chimpanzees and children perceive other species' bodies: Comparing the expert effect. Issue 6 (18th May 2020)

• Record Type: Journal Article
• Authors: Gao, Jie; Tomonaga, Masaki
• Is Part Of: Developmental science. Volume 23:Issue 6(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-05-18
• Subjects: body perception -- comparative cognition -- configural processing -- expert effect -- inversion effect; Developmental psychology -- Periodicals; Psychology, Comparative -- Periodicals; 155
• DOI: 10.1111/desc.12975
• Languages: English
• ISSNs: 1363-755X

Abstract

Abstract: 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. Abstract : This study investigated the evolutionary and developmental aspects of body perception. Chimpanzees show the inversion effect to their conspecifics, and we found their inversion effect to bodies of other species, with which they have visual or embodied experience. We report the body inversion effect in children for the first time. They also show the inversion effect to other species, suggesting the role of experience in shaping visual perception.