There is considerable evidence that animals are able to discriminate between quantities. Despite the fact that quantitative skills have been extensively studied in adult individuals, research on their development in early life is restricted to a limited number of species. We, therefore, investigated whether 2-month-old puppies could spontaneously discriminate between different quantities of food items. We used a simultaneous two-choice task in which puppies were presented with three numerical combinations of pieces of food (1 vs. 8, 1 vs. 6 and 1 vs. 4), and they were allowed to select only one option. The subjects chose the larger of the two quantities in the 1 vs. 8 and the 1 vs. 6 combinations but not in the 1 vs. 4 combination. Furthermore, the last quantity the puppies looked at before making their choice and the time spent looking at the larger/smaller amounts of food were predictive of the choices they made. Since adult dogs are capable of discriminating between more difficult numerical contrasts when tested with similar tasks, our findings suggest that the capacity to discriminate between quantities is already present at an early age, but that it is limited to very easy discriminations.

中文翻译：

---

幼犬（犬天狼犬）中的食物数量歧视。

有大量证据表明动物能够区分数量。尽管已经对成年个体进行了广泛的定量技能研究，但有关其在早期生活中的发展的研究仅限于少数物种。因此，我们调查了两个月大的幼犬是否可以自发地区分不同数量的食物。我们使用了同时进行的两项选择任务，其中给小狗提供了食物的三种数值组合（1对8、1对6和1对4），并且只允许他们选择一个选项。受试者选择了1对8和1对6组合中两个量中的较大者，而不是1对4组合。此外，幼犬在做出选择之前所查看的最后数量以及花在看更多/更少食物上的时间可以预测他们所做的选择。由于成年犬在进行类似任务测试时能够区分更困难的数值对比，因此我们的发现表明，区分数量的能力早已存在，但仅限于非常容易的区分。