Hauser Marc D, Tsao Fritz, Garcia Patricia, Spelke Elizabeth S
Department of Psychology, Harvard University, Cambridge, MA 02138, USA.
Proc Biol Sci. 2003 Jul 22;270(1523):1441-6. doi: 10.1098/rspb.2003.2414.
Although animals of many species have been shown to discriminate between visual-spatial arrays or auditory-temporal sequences based on numerosity, most of the evidence for numerosity discrimination derives from experiments involving extensive laboratory training. Under these conditions, animals' discrimination of two numerosities depends on their ratio and is independent of their absolute value. It is an open question whether any untrained non-human animal spontaneously represents number in this way, as do human children and adults. We present the results of familiarization-discrimination experiments on cotton-top tamarin monkeys (Saguinus oedipus) that provide evidence for numerosity discrimination in the absence of training. Presented with auditory stimuli (speech syllables) controlled for the continuous variables of sequence duration, item duration, inter-stimulus interval and overall energy, tamarins readily discriminated sequences of 4 versus 8, 4 versus 6, and 8 versus 12 syllables. By contrast, tamarins failed to discriminate sequences of 4 versus 5 and 8 versus 10 syllables, providing evidence that their numerosity discrimination is approximate and shows the ratio signature of numerosity discrimination in humans and trained non-human animals. These results provide strong support for the hypothesis that representations of large, approximate numerosity are evolutionarily ancient and spontaneously available to non-human animals.
尽管许多物种的动物已被证明能够根据数量区分视觉空间阵列或听觉时间序列，但大多数数量辨别证据都来自涉及广泛实验室训练的实验。在这些条件下，动物对两种数量的辨别取决于它们的比例，而与它们的绝对值无关。未经训练的非人类动物是否像人类儿童和成年人那样以这种方式自发地表征数字，这还是一个悬而未决的问题。我们展示了对棉顶狨猴（Saguinus oedipus）进行的熟悉-辨别实验结果，这些结果为未经训练时的数量辨别提供了证据。当呈现出针对序列持续时间、项目持续时间、刺激间隔和总能量等连续变量进行控制的听觉刺激（语音音节）时，狨猴能够轻松地区分4个与8个、4个与6个以及8个与12个音节的序列。相比之下，狨猴无法区分4个与5个以及8个与10个音节的序列，这表明它们的数量辨别是近似的，并且显示出人类和经过训练的非人类动物数量辨别中的比例特征。这些结果为以下假设提供了有力支持：对大的、近似数量的表征在进化上是古老的，并且非人类动物可以自发获得。
