Inoue-Nakamura N, Matsuzawa T
Department of Psychology, Kwansei Gakuin University, Nishinomiya, Japan.
J Comp Psychol. 1997 Jun;111(2):159-73. doi: 10.1037/0735-7036.111.2.159.
At the age of 3.5 years, wild chimpanzees at Bossou, Guinea, begin to use hammer and anvil stones to crack oil-palm nuts to get the kernels. To clarify the developmental processes, the authors did a field experiment in which stones and oil-palm nuts were provided. Infant chimpanzees' stone-nut manipulation was observed and video recorded. Data were collected from 3 infants younger than 4 years old from 1992 to 1995. The authors analyzed 692 episodes of infants' stone-nut manipulation and 150 episodes of infants' observation of nut cracking performed by adults. Infants observed other chimpanzees' nut cracking and got the kernels from them. The stone-nut manipulation developed from a single action on a single object to multiple actions on multiple objects. Although infant chimpanzees at the age of 2.5 years already acquired basic actions necessary for nut cracking, they did not combine the actions in an appropriate sequence to perform actual nut cracking.
在几内亚博苏的野生黑猩猩3.5岁时开始使用锤子和砧板石头砸开油棕榈坚果以获取果仁。为了阐明其发育过程，作者进行了一项野外实验，提供了石头和油棕榈坚果。观察并录制了幼年黑猩猩对石头和坚果的操作。数据收集自1992年至1995年的3只4岁以下的幼崽。作者分析了692次幼崽对石头和坚果的操作片段以及150次幼崽观察成年黑猩猩砸坚果的片段。幼崽观察其他黑猩猩砸坚果并从它们那里获取果仁。对石头和坚果的操作从对单个物体的单一动作发展到对多个物体的多个动作。虽然2.5岁的幼年黑猩猩已经掌握了砸坚果所需的基本动作，但它们并没有以适当的顺序组合这些动作来实际砸开坚果。
