Furlong E E, Boose K J, Boysen S T
Department of Psychology, The Ohio State University, 209 Psychology Building, 1835 Neil Ave., Columbus, OH 43210-1222, USA.
Anim Cogn. 2008 Jan;11(1):83-97. doi: 10.1007/s10071-007-0091-6. Epub 2007 May 22.
Recent evidence for different tool kits, proposed to be based upon culture-like transmission, have been observed across different chimpanzee communities across Western Africa. In light of these findings, the reported failures by seven captive juvenile chimpanzees tested with 27 tool use tasks (Povinelli 2000) seem enigmatic. Here we report successful performance by a group of nine captive, enculturated chimpanzees, and limited success by a group of six semi-enculturated chimpanzees, on two of the Povinelli tasks, the Flimsy Tool task, and the Hybrid Tool task. All chimpanzees were presented with a rake with a flimsy head and a second rake with a rigid head, either of which could be used to attempt to retrieve a food reward that was out of reach. The rigid rake was constructed such that it had the necessary functional features to permit successful retrieval, while the flimsy rake did not. Both chimpanzee groups in the present experiment selected the functional rigid tool correctly to use during the Flimsy Tool task. All animals were then presented with two "hybrid rakes" A and B, with one half of each rake head constructed from flimsy, non-functional fabric, and the other half of the head was made of wood. Food rewards were placed in front of the rigid side of Rake A and the flimsy side of Rake B. To be successful, the chimps needed to choose the rake that had the reward in front of the rigid side of the rake head. The fully enculturated animals were successful in selecting the functional rake, while the semi-enculturated subjects chose randomly between the two hybrid tools. Compared with findings from Povinelli, whose non-enculturated animals failed both tasks, our results demonstrate that chimpanzees reared under conditions of semi-enculturation could learn to discriminate correctly the necessary tool through trial-and-error during the Flimsy Tool task, but were unable to recognize the functional relationship necessary for retrieving the reward with the "hybrid" rake. In contrast, the enculturated chimpanzees were correct in their choices during both the Flimsy Tool and the Hybrid Tool tasks. These results provide the first empirical evidence for the differential effects of enculturation on subsequent tool use capacities in captive chimpanzees.
最近有证据表明，在西非不同的黑猩猩群落中观察到了不同的工具组合，这些工具组合被认为是基于类似文化的传播方式形成的。鉴于这些发现，之前报道的7只圈养幼年黑猩猩在27项工具使用任务测试中表现失败（波维内利，2000年），这似乎令人费解。在此，我们报告了一组9只圈养的、经过文化熏陶的黑猩猩在波维内利的两项任务——脆弱工具任务和混合工具任务中取得了成功，还有一组6只半文化熏陶的黑猩猩取得了有限的成功。所有黑猩猩面前都有一把头部脆弱的耙子和一把头部坚硬的耙子，它们都可以用来尝试获取够不到的食物奖励。坚硬的耙子被制作得具备成功获取奖励所需的功能特性，而脆弱的耙子则不具备。在本实验中，两组黑猩猩在脆弱工具任务中都正确地选择了功能性的坚硬工具来使用。然后，所有动物面前都有两个“混合耙子”A和B，每个耙子头部的一半由脆弱的、无功能的织物制成，另一半头部由木材制成。食物奖励被放置在耙子A坚硬一侧的前方和耙子B脆弱一侧的前方。要成功完成任务，黑猩猩需要选择奖励位于耙子头部坚硬一侧前方的耙子。完全经过文化熏陶的动物成功地选择了功能性耙子，而半文化熏陶的受试对象在两个混合工具之间随机选择。与波维内利的研究结果相比，他的未经过文化熏陶的动物在两项任务中都失败了，我们的结果表明，在半文化熏陶条件下饲养的黑猩猩能够在脆弱工具任务中通过试错学会正确区分必要的工具，但无法识别使用“混合”耙子获取奖励所需的功能关系。相比之下，经过文化熏陶的黑猩猩在脆弱工具任务和混合工具任务中的选择都是正确的。这些结果为文化熏陶对圈养黑猩猩后续工具使用能力的不同影响提供了首个实证证据。
