Markowitz H, Schmidt M, Nadal L, Squier L
J Appl Behav Anal. 1975 Fall;8(3):333-5. doi: 10.1901/jaba.1975.8-333.
Three adult female elephants (Elephas maximus) were tested on a light-dark discrimination problem with an 8-yr intertrial interval. The first subject took only 6 min to reach criterion and made only two errors, suggesting remarkable retention. The other two subjects were found to have visual anomalies that would have gone undetected without this research.
三只成年雌性大象（印度象）接受了一项明暗辨别问题测试，试验间隔为8年。第一个受试者只用了6分钟就达到了标准，并且只犯了两个错误，这表明其具有显著的记忆保持能力。另外两只受试者被发现有视觉异常，若没有这项研究，这些异常可能不会被发现。
