How do chimpanzees and children perceive other species: use of embodied and visual experience

抄録

This study aims to investigate how chimpanzees and children process bodies of other species and which kinds of cues they use, including embodied and visual experience. Previous research has found that human adults show the inversion effect to bodies of conspecifics and other species that they have visual or embodied expertise with, that is, they are better at recognizing the bodies when they are upright than inverted. The inversion effect is not found for other objects. In this study, we tested the inversion effect in seven adult chimpanzees and 33 children (43-75 months old). For chimpanzees, we used stimuli of crawling humans, horses (they have no visual experience with them but they share the quadrupedal postures), bipedal humans with visually familiar postures and unfamiliar postures. For children, we used stimuli of humans (conspecific), chimpanzees (not familiar), horses (familiar), and houses (other objects). They did recognition tasks with upright and inverted stimuli on touch screen computers. For chimpanzees, they showed the inversion effect to crawling humans, horses, and bipedal humans with familiar postures. It suggests that they use both embodied and visual experience when processing other species' bodies. For children, they showed the inversion effect to humans, chimpanzees and horses. It suggests that children are more sensitive to visual experience cues than chimpanzees, because they have limited visual experience with chimpanzee bodies but still showed the expert-only inversion effect. There was no change in the inversion effect with age, suggesting that the use of visual experience in children is stable in the pre-school phase.