The Alex Foundation, 30 Curry Circle, Swampscott, USA.
Messerli Research Institute, University of Veterinary Medicine Vienna, Vienna, Austria.
Sci Rep. 2022 Oct 18;12(1):17415. doi: 10.1038/s41598-022-21370-6.
Contrafreeloading-working to access food that could be freely obtained-is rarely exhibited and poorly understood. Based on data from Grey parrots (Psittacus erithacus), researchers proposed a correlation between contrafreeloading and play: that contrafreeloading is more likely when subjects view the task as play. We tested that hypothesis by subjecting a relatively more playful parrot species, the kea (Nestor notabilis), to the same experimental tasks. Experiment 1 presented eight kea with container pairs holding more- or less-preferred free or enclosed food items, and examined three types of contrafreeloading: calculated (working to access preferred food over less-preferred, freely available food); classic (working to access food identical to freely available food); and super (working to access less-preferred food over preferred, freely available food). At the group level, the kea behaved similarly to the Greys: They significantly preferred calculated contrafreeloading, performed classic contrafreeloading at chance, and significantly failed to super contrafreeload. However, overall kea engaged in more contrafreeloading than Greys. Experiment 2 examined a potentially more ecologically relevant task, a choice between shelled and unshelled walnuts. No kea contrafreeloaded for nuts, whereas two of five Greys significantly preferred nut contrafreeloading and one chose at chance. We examine proximate and adaptive explanations for the performances of these differentially playful parrot species to further elucidate the role of play in contrafreeloading.
反劳作——努力获取本可自由获取的食物——很少被表现出来，也未被很好地理解。基于灰鹦鹉（Psittacus erithacus）的数据，研究人员提出了反劳作与玩耍之间的相关性：当实验对象将任务视为玩耍时，反劳作更有可能发生。我们通过让一种相对更具玩耍性的鹦鹉物种——啄羊鹦鹉（Nestor notabilis）参与相同的实验任务来检验这一假设。实验 1 为 8 只啄羊鹦鹉提供了一对容器，容器中装有更受喜爱或较不受喜爱的自由或封闭食物，研究了三种类型的反劳作：计算型（为获取偏好的食物而工作，而不是偏好的、自由可得的食物）；经典型（为获取与自由可得的食物相同的食物而工作）；和超级型（为获取较不受喜爱的食物而工作，而不是偏好的、自由可得的食物）。在群体水平上，啄羊鹦鹉的行为与灰鹦鹉相似：它们显著偏好计算型反劳作，以机会水平执行经典型反劳作，而显著未能执行超级型反劳作。然而，总体而言，啄羊鹦鹉的反劳作行为比灰鹦鹉更多。实验 2 研究了一个潜在更具生态相关性的任务，即在带壳和不带壳的核桃之间进行选择。没有啄羊鹦鹉会为了坚果而反劳作，而五只灰鹦鹉中有两只明显更喜欢坚果反劳作，一只则随机选择。我们探讨了这些具有不同玩耍性的鹦鹉物种表现的近因和适应解释，以进一步阐明玩耍在反劳作中的作用。
