Beran Michael J, Evans Theodore A, Leighty Katherine A, Harris Emily H, Rice Daniel
Language Research Center, Georgia State University, Atlanta, Georgia 30303, USA.
Am J Primatol. 2008 Feb;70(2):191-4. doi: 10.1002/ajp.20474.
Capuchin monkeys (Cebus apella) were presented with two sets of food items, identical in food type but differing in number. Animals selected one set and were permitted to consume their choice. Set sizes ranged from 1 to 6 items. In experiment 1, each set was uncovered and recovered before a response was made, and the monkeys selected the larger set at high levels. Experiment 2 presented sets that had both visible and nonvisible food items in them at the time of the response, thus requiring the monkeys to sum the total amount of food that was available. The monkeys again selected the larger set with no decrement in performance. Overall, the data indicate that capuchins, like other more extensively studied primate species in this area of research, are responsive to quantitative differences between sets. Capuchins succeed in making these quantity judgments when sets are nonvisible at choice time and when summation of items must be performed, thus demonstrating coordination of quantification skills and memory. Capuchins also inhibit responses to visible food items when those items are only part of an overall smaller quantity of food compared with a completely nonvisible set.
给卷尾猴（僧帽猴）呈现两组食物，食物类型相同但数量不同。动物选择其中一组并被允许吃掉它们所选的食物。每组食物的数量从1到6个不等。在实验1中，每组食物在做出反应前先被揭开然后再盖上，猴子在很大程度上选择了数量更多的那一组。实验2呈现的几组食物在做出反应时既有可见的食物也有不可见的食物，因此要求猴子计算出可用食物的总量。猴子再次选择了数量更多的那一组，且表现没有下降。总体而言，数据表明卷尾猴与在该研究领域中其他经过更广泛研究的灵长类物种一样，对两组之间的数量差异有反应。当在选择时两组食物不可见且必须计算食物数量总和时，卷尾猴成功地做出了这些数量判断，从而证明了量化技能和记忆的协调。当与完全不可见的一组食物相比，可见食物只是总量较少的一部分时，卷尾猴也会抑制对可见食物的反应。
