Department of Zoology, Faculty of Biological Science, University of South Bohemia, Branisovská 31, 370 05 Ceské Budejovice, Czech Republic.
Anim Cogn. 2010 Jul;13(4):609-15. doi: 10.1007/s10071-010-0311-3. Epub 2010 Feb 4.
Amodal completion enables an animal to perceive partly concealed objects as an entirety, and to interact with them appropriately. Several studies, based upon either operant conditioning or filial imprinting techniques, have shown that various animals (both mammals and birds) can perform amodal completion. Before this study, the use of amodal completion by untrained animals in the recognition of objects had not been considered. Using two feeders, we observed in a field experiment the reaction of tits to the torso of a sparrowhawk (partly occluded or an 'amputated' dummy) in two different treatments (sparrowhawk torso vs. complete dummy pigeon; and torso vs. complete dummy sparrowhawk). It is clear that the birds considered the two torso variants as predators and kept away from both of them when the second feeder offered a 'pigeon' instead. On the other hand, when a 'complete sparrowhawk' was present on the second feeder, the number of visits to the occluded torso remained low; while the number of visits to the amputated one increased threefold. Birds risked perching near what was clearly an amputated torso; while the fear of a "hiding" (occluded) torso remained unchanged, when the second feeder did not provide a safe alternative. Such discrimination between torsos requires the ability for amodal completion. Our results demonstrate that in their recognition process, the birds not only use simple sign stimuli, but also complex cognitive functions.
无模态完型感知使动物能够将部分隐藏的物体视为整体，并进行适当的互动。几项基于操作性条件反射或雏鸟印记技术的研究表明，许多动物（包括哺乳动物和鸟类）都能够进行无模态完型感知。在这项研究之前，未经训练的动物在识别物体时是否使用无模态完型感知尚未得到考虑。我们使用两个喂食器，在野外实验中观察到山雀对雀鹰（部分遮挡或“截肢”的假鸟）的反应，实验采用两种处理方式（雀鹰躯干与完整的假鸽；以及躯干与完整的假雀鹰）。显然，鸟类将两种躯干变体视为捕食者，当第二个喂食器提供“鸽子”时，它们会远离这两种变体。另一方面，当第二个喂食器上出现“完整的雀鹰”时，对遮挡躯干的访问次数仍然较低；而对截肢躯干的访问次数增加了三倍。鸟类冒险在明显的截肢躯干附近栖息；而当第二个喂食器没有提供安全的替代品时，对隐藏（遮挡）躯干的恐惧仍然不变。这种对躯干的区分需要无模态完型感知的能力。我们的研究结果表明，在识别过程中，鸟类不仅使用简单的符号刺激，还使用复杂的认知功能。
