Beran Michael J
Language Research Center, Georgia State University, 3401 Panthersville Road, Decatur, GA 30034, USA.
Anim Cogn. 2004 Apr;7(2):86-92. doi: 10.1007/s10071-003-0191-x. Epub 2003 Sep 18.
As previously reported (Beran and Rumbaugh, 2001), two chimpanzees used a joystick to collect dots, one-at-a-time, on a computer monitor, and then ended a trial when the number of dots collected was equal to the Arabic numeral presented for the trial. Here, the chimpanzees were presented with the task again after an interval of 6 months and then again after an additional interval of 3.25 years. During each interval, the chimpanzees were not presented with the task, and this allowed an assessment of the extent to which both animals retained the values of each Arabic numeral. Despite lower performance at each retention interval compared to the original study, both chimpanzees performed above chance levels in collecting a quantity of dots equal to the target numeral, one chimpanzee for the numerals 1-7, and the second chimpanzee for the numerals 1-6. For the 3.25-year retention, errors were more dispersed around each target numeral than in the original study, but the chimpanzees' performances again appeared to be based on a continuous representation of magnitude rather than a discrete representation of number. These data provide an experimental demonstration of long-term retention of the differential values of Arabic numerals by chimpanzees.
如先前报道（贝兰和伦博，2001年），两只黑猩猩使用操纵杆在电脑显示器上逐个收集圆点，当收集的圆点数量等于该试验中呈现的阿拉伯数字时结束试验。在此，6个月后再次让黑猩猩执行该任务，之后又在额外间隔3.25年后再次执行。在每个间隔期内，黑猩猩未执行该任务，这使得能够评估两只动物对每个阿拉伯数字数值的保留程度。尽管与原始研究相比，在每个保留期的表现较低，但两只黑猩猩在收集与目标数字相等数量的圆点时均表现高于随机水平，一只黑猩猩针对数字1 - 7，另一只黑猩猩针对数字1 - 6。对于3.25年的保留期，误差在每个目标数字周围比原始研究中更为分散，但黑猩猩的表现再次似乎基于数量的连续表征而非数字的离散表征。这些数据为黑猩猩对阿拉伯数字差值的长期保留提供了实验证明。
