Development of object manipulation and tool use in chimpanzees (Pan troglodytes) and bonobos (Pan paniscus)

在人类婴儿中，组合操作作为工具使用的先驱似乎很重要。以前的研究表明，在生命的第一年，人类和黑猩猩在物体操纵方面的发展相似性，但从第二年开始，黑猩猩延迟了分离物体的组合。然而，对黑猩猩组合操作发展的系统研究直到最近才开始。这些研究比较了结合的产物和所采用的结合过程，以及这些产物和过程是如何被chmpanzees和人类共享的。对这两个物种产生的行为进行比较，可以阐明认知的特征是如何从身体与环境的相互作用中产生的，并为阐明人类行为和认知的起源提供了一种强有力的方法。本研究以黑猩猩及其近亲倭黑猩猩为研究对象，探讨了它们与人类婴儿的组合操作和工具使用的异同。进行了几个实验，观察到两个物种之间的任务，即“重复”的行动，“调整”的行动，“逆转”的行动，和“转移”的注意力之间的共同运动特征。人类、黑猩猩和倭黑猩猩在操纵多个物体以完成包括使用工具在内的任务时会共享这些动作。重复、调整、反转动作和转移注意力是这两个物种共同的更高认知水平的基础。然而，在黑猩猩和倭黑猩猩中几乎看不到工具使用的子组件模式。此外，受试者没有再现模型的行为，一个组件模式的工具使用，由人类示范。这一结果可以从层级行为的产生和语言的进化两个方面来讨论。

In human infants, combinatory manipulation seems important as a precursor of tool use. Previous studies have suggested developmental similarities in object manipulation in humans and chimpanzees during the 1st year of life but delayed combination of detached objects for chimpanzees from the 2nd year onward. Systematic studies on the development of combinatory manipulation in chimpanzees, however, have only recently started. These studies compared both the products of combination and the combinatory processes adopted and how these are shared by chmpanzees and humans. Such comparisons of actions generated by both species can illuminate how features of cognition may arise from bodily interactions with the environment and provide a powerful methodology to clarify origins of human behavior and cognition. The present study focused on combinatory manipulation and tool use by chimpanzees and their closest relative, bonobos, aiming to clarify the similarities with and the differences from that by human infants. Several experiments were conducted and common motor characteristics were observed across the tasks between both species, namely "repetition" of actions, "adjustment" of actions, "reversal" of actions, and "shifts" of attention. Humans, chimpanzees and bonobos share these actions when manipulating multiple objects to complete tasks which include tool use. Repetition, adjustment, and reversal of actions and shifts of attention underlie higher levels of cognition common to both species. However, subassembly patterns of tool use were hardly seen in both chimpanzees and bonobos. In addition, subjects did not reproduce the model behaviors, a subassembly pattern of tool use, by a human demonstrator. The results could be discussed in terms of generation of hierarchical actions and evolution of language.