Department of General Psychology, University of Padua, Padua, Italy.
Department of Psychology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA.
Biol Lett. 2022 Feb;18(2):20210426. doi: 10.1098/rsbl.2021.0426. Epub 2022 Feb 9.
Animals show vast numerical competence in tasks that require both ordinal and cardinal numerical representations, but few studies have addressed whether animals can identify the numerical middle in a sequence. Two rhesus monkeys () learned to select the middle dot in a horizontal sequence of three dots on a touchscreen. When subsequently presented with longer sequences composed of 5, 7 or 9 items, monkeys transferred the middle rule. Accuracy decreased as the length of the sequence increased. In a second test, we presented monkeys with asymmetrical sequences composed of nine items, where the numerical and spatial middle were distinct and both monkeys selected the numerical middle over the spatial middle. Our results demonstrate that rhesus macaques can extract an abstract numerical rule to bisect a discrete set of items.
动物在需要顺序和基数数值表示的任务中表现出广泛的数值能力,但很少有研究探讨动物是否能够识别序列中的数值中间。两只恒河猴学会了在触摸屏上的水平三个点序列中选择中间点。当随后呈现由 5、7 或 9 个项目组成的更长序列时,猴子转移了中间规则。随着序列长度的增加,准确性降低。在第二个测试中,我们向猴子呈现了由九个项目组成的不对称序列,其中数值和空间中间是不同的,两只猴子都选择了数值中间而不是空间中间。我们的结果表明,恒河猴可以提取一个抽象的数值规则来将离散的一组项目二等分。