Spontaneous discrimination of small quantities: shoaling preferences in angelfish (Pterophyllum scalare)
Spontaneous discrimination of small quantities: shoaling preferences in angelfish (Pterophyllum scalare)
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DOI：
10.1007/s10071-011-0392-7
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发表时间：
2011-07-01
期刊：
影响因子：
2.7
通讯作者：
Gerlai, Robert
中科院分区：
文献类型：
--
作者：
Gomez-Laplaza, Luis M.;Gerlai, Robert
量化的能力，即估计数量的能力，可能在某些情况下提供进化优势，并已在各种动物物种中得到证明。在之前的一项研究中，我们发现天使鱼（鳞翼鱼）能够区分大量同种鱼更喜欢加入较大的鱼群的群体（鱼群）。我们的研究结果表明，天使鱼可以根据鱼群的一些定量属性来比较相对鱼群的大小。在这里，同样使用二元偏好测试，我们检查了天使鱼是否能够区分少量同种鱼的鱼群，如果是这样，它们的表现是否揭示了一种与人类和非人类动物的少量区分类似的潜在机制，即计数能力的可能先驱。我们的研究结果表明，鱼可靠地选择4对1,3对1,2对1,3对2，但在4对3,5对4,6对5之间进行选择时，鱼的表现水平处于偶然水平。实验结果还表明，刺激鱼群中鱼的密度对实验天使鱼的表现没有显著影响。这些结果与存在一种在脊椎动物中辨别少量元素的对象文件机制的假设相一致，并为天使鱼中多达三种元素的自发辨别提供了证据，这与在人类和非人类动物中发现的限制相似。这些发现增加了越来越多的数据，表明不同数量的物品之间的歧视机制可能在不同的分类群中共享，并且具有进化的古老起源。
The ability to quantify, i.e. to estimate quantity, may provide evolutionary advantages in some contexts and has been demonstrated in a variety of animal species. In a prior study, we showed that angelfish (Pterophyllum scalare) were able to discriminate between groups (shoals) in which a large number of conspecifics swam preferring to join the larger of the two. Our results implied that angelfish can compare relative shoal sizes likely on the basis of some quantitative attributes of the shoal. Here, also using a binary preference test, we examined whether angelfish are able to discriminate between shoals of small numbers of conspecifics, and if so whether their performance reveals a comparable underlying mechanism to that proposed for discrimination of small quantities in human and non-human animals, namely the possible precursor of the ability to count. Our results demonstrate that fish reliably chose 4 versus 1, 3 versus 1, 2 versus 1 and 3 versus 2 individuals, but were at chance performance level when having to choose between 4 versus 3, 5 versus 4 and 6 versus 5. Findings also reveal that the density of the fish in the stimulus shoals did not significantly affect the performance of experimental angelfish. These results are compatible with the hypothesis of the existence of an object-file mechanism to discriminate small quantities in vertebrates and provide evidence for spontaneous discrimination of up to three elements in angelfish, a similar limit to that found in human and non-human animals. The findings add to the growing body of data, suggesting that the mechanisms underlying discrimination between different quantities of items may be shared across different taxa and have an evolutionary ancient origin.