Spontaneous discrimination of food quantities in the jungle crow, Corvus macrorhynchos
Spontaneous discrimination of food quantities in the jungle crow, Corvus macrorhynchos
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DOI：
10.1016/j.anbehav.2014.05.012
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发表时间：
2014-08-01
期刊：
影响因子：
2.5
通讯作者：
Sugita, Shoei
中科院分区：
文献类型：
--
作者：
Bogale, Bezawork Afework;Aoyama, Masato;Sugita, Shoei
尽管对动物的数字判断进行了大量研究，但关于训练的潜在机制和作用仍然存在不确定性。为了解决这些问题，我们研究了丛林乌鸦的数量歧视，以前的研究表明，在训练后，这些乌鸦会选择两个量中较大的一个。在目前的研究中，我们检查了丛林乌鸦是否能够在没有事先训练的情况下区分不同数量的食物。使用同时进行的两种选择测试，我们研究了它们的表现是否揭示了在其他动物中用于区分小数量和大数量的潜在机制。首先，对丛林乌鸦进行测试，在两个离散的同质量之间进行选择；一个较小，一个较大，比率为0.5(1对2，2对4和4对8)，0.67(2对3，4对6和8对12)和0.75(3对4，6对8和12对16)。然后，我们使用非数字线索进行了一项测试，其中比较刺激的体积是相等的。在所有的比较中，丛林乌鸦选择了两个量中较大的一个，除了当两个量都很大时(6对8，8对12和12对16)。此外，选择较大数量的准确度随着数值大小的增加而下降。这些结果表明，在自发的辨别任务中，丛林乌鸦使用对象文件机制来比较数量，即使其中一个数组中的项目数量超过四个。去掉音量提示时，乌鸦没有表现出对较小或较大数量的偏好。这种偏见的缺乏可能表明，选择食物数量较多的地区可能是一种生态作用，而不一定是丛林乌鸦最佳觅食的确切食物数量。(C)2014年动物行为研究协会。爱思唯尔有限公司出版。保留所有权利。
Despite considerable research on numeric judgements in animals, uncertainty remains about both the underlying mechanisms and the role of training. To address these issues, we study quantity discrimination in jungle crows that have previously been shown to select the larger of two quantities following training. In the current study, we examined whether jungle crows are able to discriminate between different quantities of food items without prior training. Using a simultaneous two-alternative test, we studied whether their performance reveals the underlying mechanism being used for discrimination of small and large quantities in other animals. First, jungle crows were tested with a choice between two discrete homogeneous quantities; one smaller and one larger, with ratios of 0.5 (1 versus 2, 2 versus 4 and 4 versus 8), 0.67 (2 versus 3, 4 versus 6 and 8 versus 12) and 0.75 (3 versus 4, 6 versus 8 and 12 versus 16). Then, we conducted a test using a non-numerical cue where the volume of comparison stimuli was equalized. Jungle crows selected the larger of the two quantities in all comparisons, except those when both quantities were large (6 versus 8, 8 versus 12 and 12 versus 16). Furthermore, accuracy of selection of the larger quantity declined with increasing numerical magnitude. These results suggest that in a spontaneous discrimination task, jungle crows use an object-file mechanism to compare quantities, even when the number of items in one of the arrays exceeds four. The crows showed no preference for the smaller or the larger quantity when the volume cue was removed. This lack of bias may suggest an ecological role of selection for a patch with higher amounts of food and not necessarily the exact number of food items for optimal foraging in jungle crows. (C) 2014 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.