Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria.
Department of Cognitive Biology University of Vienna, Vienna, Austria.
PLoS One. 2018 Nov 7;13(11):e0205429. doi: 10.1371/journal.pone.0205429. eCollection 2018.
The ability to innovatively use or even manufacture different tools depending on a current situation can be silhouetted against examples of stereotyped, inborn tool use/manufacture and is thus often associated to advanced cognitive processing. In this study we confronted non-specialized, yet innovative tool making birds, Goffin's cockatoos (Cacatua goffiniana), with an apparatus featuring an out-of-reach food reward that could be placed at different distances from a tool opening. Alternatively, the food stayed at a constant distance but the tool opening in the front of the apparatus had different diameters. We used a novel material for tool manufacture (cardboard) that demanded an incrementally increased manufacturing effort from the actor, depending on the length of the tool required. We found that our subjects used two strategies to succeed in this tasks: either by making carboard-stripe tools using the full length of the material sheets originally offered or by adjusting the lengths of their tools to different goal distances. Subjects also discarded cardboard stripes that were too short to reach the goal prior to use and discarded longer pieces when the goal was further away than when it was close. Nevertheless, likely due to morphological constraints, the birds failed to adjust the widths of their tools depending on the diameter of the tool opening.
根据当前情况创新性地使用甚至制造不同工具的能力，可以与刻板的、天生的工具使用/制造的例子形成鲜明对比，因此通常与高级认知处理相关联。在这项研究中，我们让非专业但具有创新性的制造工具的鸟类——戈芬氏凤头鹦鹉（Cacatua goffiniana），面对一种带有遥不可及食物奖励的设备，该设备可以将食物放在距离工具开口不同的距离处。或者，食物保持在固定的距离，但设备前部的工具开口具有不同的直径。我们使用了一种新颖的制造工具的材料（硬纸板），根据所需工具的长度，要求行为者逐步增加制造工作。我们发现，我们的研究对象使用了两种策略来成功完成这些任务：要么使用最初提供的材料片的全长制作硬纸板条工具，要么根据目标距离调整工具的长度。研究对象还会在使用前丢弃无法触及目标的过短的硬纸板条，并在目标距离较远时丢弃较长的硬纸板条。然而，可能由于形态限制，鸟类无法根据工具开口的直径调整工具的宽度。
