Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2009, Neuchâtel, Switzerland.
Anim Cogn. 2013 Jan;16(1):35-43. doi: 10.1007/s10071-012-0548-0. Epub 2012 Aug 14.
Although cooperative behaviours are common in animals, the cognitive processes underpinning such behaviours are very likely to differ between species. In humans, other-regarding preferences have been proposed to sustain long-term cooperation between individuals. The extent to which such psychological capacities exist in other animals is still under investigation. Five hand-reared ravens were first tested in an experiment where they could provide food to a conspecific at no cost to themselves. We offered them two behavioural options that provided identical amounts of food to the actor and where one of the two options additionally delivered a reward to a recipient. Subsequently, we made the ravens play a no-cost cooperation game with an experimenter. The experimenter had the same options as the animals and matched the ravens' choices, making the prosocial choice the more profitable option. In both conditions, ravens were indifferent to the effects of their choices and hence failed to help conspecifics and to cooperate with the experimenter. While our negative results should be interpreted with care, overall, our findings suggest that the ravens had no understanding of the consequences of their actions for a potential recipient. This study adds to several others that have used a similar set-up and have reported negative results on other-regarding preferences in animals.
虽然合作行为在动物中很常见,但支持这些行为的认知过程在不同物种之间很可能有所不同。在人类中,有人提出了利他偏好来维持个体之间的长期合作。其他动物是否存在这种心理能力仍在研究之中。我们首先对五只经过人工饲养的乌鸦进行了一项实验,在实验中,它们可以在不花费自己任何代价的情况下为同类提供食物。我们为它们提供了两种行为选择,这两种选择都能为施动者提供等量的食物,其中一种选择还会给接受者带来奖励。随后,我们让乌鸦与一名实验员进行了无成本的合作游戏。实验员有与动物相同的选择,并与乌鸦的选择相匹配,使亲社会选择成为更有利可图的选择。在这两种情况下,乌鸦对自己选择的结果漠不关心,因此没有帮助同类,也没有与实验员合作。虽然我们的负面结果应该谨慎解释,但总的来说,我们的发现表明,这些乌鸦并不理解它们的行为对潜在接受者的后果。这项研究增加了其他几项使用类似设置并报告了动物的利他偏好的负面结果的研究。