Department of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
Proc Biol Sci. 2010 Sep 7;277(1694):2637-43. doi: 10.1098/rspb.2010.0285. Epub 2010 Apr 21.
Apes, corvids and parrots all show high rates of behavioural innovation in the wild. However, it is unclear whether this innovative behaviour is underpinned by cognition more complex than simple learning mechanisms. To investigate this question we presented New Caledonian crows with a novel three-stage metatool problem. The task involved three distinct stages: (i) obtaining a short stick by pulling up a string, (ii) using the short stick as a metatool to extract a long stick from a toolbox, and finally (iii) using the long stick to extract food from a hole. Crows with previous experience of the behaviours in stages 1-3 linked them into a novel sequence to solve the problem on the first trial. Crows with experience of only using string and tools to access food also successfully solved the problem. This innovative use of established behaviours in novel contexts was not based on resurgence, chaining and conditional reinforcement. Instead, the performance was consistent with the transfer of an abstract, causal rule: 'out-of-reach objects can be accessed using a tool'. This suggests that high innovation rates in the wild may reflect complex cognitive abilities that supplement basic learning mechanisms.
在野外，猿类、鸦科鸟类和鹦鹉都表现出很高的行为创新率。然而，目前尚不清楚这种创新行为是否基于比简单学习机制更复杂的认知。为了研究这个问题，我们向新喀里多尼亚乌鸦展示了一个新的三阶段元工具问题。任务涉及三个不同的阶段：（i）通过拉起一根绳子获得一根短棍，（ii）使用短棍作为元工具从工具箱中取出一根长棍，最后（iii）使用长棍从一个洞中取出食物。有过前两个阶段行为经验的乌鸦将它们链接成一个新的序列，在第一次尝试中就解决了问题。有过仅使用绳子和工具获取食物经验的乌鸦也成功地解决了问题。这种在新环境中对既定行为的创新性使用并不是基于复现、连锁和条件强化。相反，这种表现与抽象因果规则的转移是一致的：“使用工具可以获取够不着的物体”。这表明，野外的高创新率可能反映了补充基本学习机制的复杂认知能力。
