Social Network Analysis Shows Direct Evidence for Social Transmission of Tool Use in Wild Chimpanzees
Social Network Analysis Shows Direct Evidence for Social Transmission of Tool Use in Wild Chimpanzees
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DOI：
10.1371/journal.pbio.1001960
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发表时间：
2014-09-01
期刊：
影响因子：
9.8
通讯作者：
Gruber, Thibaud
中科院分区：
文献类型：
--
作者：
Hobaiter, Catherine;Poisot, Timothee;Gruber, Thibaud
社会网络分析方法使测试动物的新奇行为是通过个人学习还是通过社会学习传播成为可能。然而，到目前为止，对野生种群的社会网络分析一直局限于静态模型，不能准确反映学习的动态，例如，随着时间的推移，多次观察的影响。在这里，我们提出了一种新的动态网络分析版本，它能够捕获获取的时间方面-即一个人的连续观察如何影响其对新行为的获取。我们应用这个模型来研究两种新的工具使用变种--“苔藓海绵”和“树叶海绵再利用”在乌干达布东戈森林的Sonso黑猩猩群落中的传播。黑猩猩被广泛认为是所有动物中最“文化”的物种，有39种行为被怀疑是社会习得的，其中大多数是在工具使用领域。文化假说得到了圈养黑猩猩的实验数据和一系列观测数据的支持。然而，对于野生群体来说，仍然没有关于社会学习的直接实验证据，也没有任何直接观察到行为创新的社会扩散。在这里，我们测试了静态和动态网络模型，发现强有力的证据表明，苔藓海绵的扩散模式，而不是树叶海绵的再利用，明显比个人学习更好地解释了社会。对社会传播的最保守估计占观察事件的85%，每一次新手观察到知情的个体苔藓海绵，估计学习速度增加15倍。我们的结论是，野生黑猩猩群体特有的行为变异可以在社会上学习，这进一步证明，这种文化的先决条件起源于类人猿和人类的共同祖先，远在现代人类出现之前。
Social network analysis methods have made it possible to test whether novel behaviors in animals spread through individual or social learning. To date, however, social network analysis of wild populations has been limited to static models that cannot precisely reflect the dynamics of learning, for instance, the impact of multiple observations across time. Here, we present a novel dynamic version of network analysis that is capable of capturing temporal aspects of acquisition-that is, how successive observations by an individual influence its acquisition of the novel behavior. We apply this model to studying the spread of two novel tool-use variants, "moss-sponging'' and "leaf-sponge re-use,'' in the Sonso chimpanzee community of Budongo Forest, Uganda. Chimpanzees are widely considered the most "cultural'' of all animal species, with 39 behaviors suspected as socially acquired, most of them in the domain of tool-use. The cultural hypothesis is supported by experimental data from captive chimpanzees and a range of observational data. However, for wild groups, there is still no direct experimental evidence for social learning, nor has there been any direct observation of social diffusion of behavioral innovations. Here, we tested both a static and a dynamic network model and found strong evidence that diffusion patterns of moss-sponging, but not leaf-sponge re-use, were significantly better explained by social than individual learning. The most conservative estimate of social transmission accounted for 85% of observed events, with an estimated 15-fold increase in learning rate for each time a novice observed an informed individual moss-sponging. We conclude that group-specific behavioral variants in wild chimpanzees can be socially learned, adding to the evidence that this prerequisite for culture originated in a common ancestor of great apes and humans, long before the advent of modern humans.