Language Research Center, Georgia State University, University Plaza, Atlanta, GA 30303, USA.
Anim Cogn. 2010 Jul;13(4):641-9. doi: 10.1007/s10071-010-0314-0. Epub 2010 Feb 10.
Although many studies have shown that nonhuman animals can choose the larger of two discrete quantities of items, less emphasis has been given to discrimination of continuous quantity. These studies are necessary to discern the similarities and differences in discrimination performance as a function of the type of quantities that are compared. Chimpanzees made judgments between continuous quantities (liquids) in a series of three experiments. In the first experiment, chimpanzees first chose between two clear containers holding differing amounts of juice. Next, they watched as two liquid quantities were dispensed from opaque syringes held above opaque containers. In the second experiment, one liquid amount was presented by pouring it into an opaque container from an opaque syringe, whereas the other quantity was visible the entire time in a clear container. In the third experiment, the heights at which the opaque syringes were held above opaque containers differed for each set, so that sometimes sets with smaller amounts of juice were dropped from a greater height, providing a possible visual illusion as to the total amount. Chimpanzees succeeded in all tasks and showed many similarities in their continuous quantity estimation to how they performed previously in similar tasks with discrete quantities (for example, performance was constrained by the ratio between sets). Chimpanzees could compare visible sets to nonvisible sets, and they were not distracted by perceptual illusions created through various presentation styles that were not relevant to the actual amount of juice dispensed. This performance demonstrated a similarity in the quantitative discrimination skills of chimpanzees for continuous quantities that matches that previously shown for discrete quantities.
尽管许多研究表明非人类动物可以选择两个离散数量的物品中的较大者，但对于连续数量的区分却较少受到关注。这些研究对于辨别作为比较的数量类型的功能的区分性能的异同是必要的。在三个实验中，黑猩猩在连续数量（液体）之间做出判断。在第一个实验中，黑猩猩首先在两个装有不同量果汁的透明容器之间进行选择。接下来，他们观察了两个液体量从上方的不透明注射器分配到不透明容器中。在第二个实验中，一个液体量是通过从不透明注射器倒入不透明容器中呈现的，而另一个量在整个时间都在透明容器中可见。在第三个实验中，不透明注射器上方的不透明容器的高度对于每组都不同，因此有时果汁量较小的组从较高的高度掉落，这可能会产生关于总数量的视觉错觉。黑猩猩在所有任务中都取得了成功，并且在其连续数量估计方面表现出了与他们以前在类似离散数量任务中表现出的许多相似之处（例如，性能受到组之间比率的限制）。黑猩猩可以将可见的组与不可见的组进行比较，并且不会被通过各种与实际分配的果汁量无关的呈现方式产生的感知错觉所干扰。这种表现展示了黑猩猩在连续数量上的定量区分技能的相似性，与以前在离散数量上显示的相似性相匹配。
