Shaw Rachael C, Plotnik Joshua M, Clayton Nicola S
Department of Psychology, University of Cambridge.
J Comp Psychol. 2013 Nov;127(4):428-35. doi: 10.1037/a0032010. Epub 2013 May 13.
Choice by exclusion involves selecting a rewarded stimulus by rejecting alternatives that are unlikely to be rewarded. It has been proposed that in corvids, exclusion is an adaptive specialization for caching that, together with object permanence and observational spatial memory, enhances a bird's ability to keep track of the contents of caches. Thus, caching species are predicted to perform well in tasks requiring exclusion. We tested this prediction by assessing the performance of Eurasian jays (Garrulus glandarius), a highly specialized cacher, in a two-way object choice task in which food was hidden in 1 of 2 cups. Consistent with the corvids' capacity for observational spatial memory, jays were highly accurate when shown the location of the food reward. However, the jays failed to exclude the empty cup when shown its contents. This failure to select the baited cup when shown the empty cup was possibly due to jays attending to the experimenter's movements and erroneously selecting the empty cup by responding to these local enhancement cues. To date, no corvids have been tested in an auditory two-way object choice task. Testing exclusion in the auditory domain requires that a bird use the noise produced when the baited cup is shaken to locate the reward. Although jays chose the baited cup more frequently than predicted by chance, their performance did not differ from trials controlling for the use of conflicting cues provided by the experimenter. Overall, our results provide little support for the hypothesis that caching has shaped exclusion abilities in corvids.
排除式选择涉及通过拒绝不太可能得到奖励的选项来选择一个有奖励的刺激物。有人提出，在鸦科鸟类中，排除是一种与贮藏行为相关的适应性特化，它与客体永久性和观察性空间记忆一起，增强了鸟类追踪贮藏物内容的能力。因此，预计贮藏物种在需要排除的任务中表现良好。我们通过评估欧亚松鸦（Garrulus glandarius）在一项双向物体选择任务中的表现来检验这一预测，在该任务中，食物被藏在两个杯子中的一个里。与鸦科鸟类的观察性空间记忆能力一致，当向松鸦展示食物奖励的位置时，它们的准确率很高。然而，当向松鸦展示空杯子的内容时，它们未能排除空杯子。当展示空杯子时未能选择有诱饵的杯子，可能是因为松鸦关注了实验者的动作，并通过对这些局部增强线索做出反应而错误地选择了空杯子。迄今为止，还没有鸦科鸟类在听觉双向物体选择任务中接受测试。在听觉领域测试排除能力要求鸟类利用摇动有诱饵的杯子时产生的噪音来定位奖励。尽管松鸦选择有诱饵杯子的频率高于随机预测，但它们的表现与控制实验者提供的冲突线索使用情况的试验没有差异。总体而言，我们的结果几乎没有支持贮藏行为塑造了鸦科鸟类排除能力这一假设。
