Disregarding the sensationalistic title of the BBC Earth video on youtube, I was very impressed by the work of scientists from The Primate Research Institute, Kyoto University, described here Chimp vs Human! | Memory Test | BBC Earth . First thing that came to my mind was the question how did they manage to do it? Note that a chimpanzee does not have to actually understand the meaning of each particular symbol with respect to integer quantity it represents, in order to perform this task, but it has to understand exactly and precisely the order of symbols. If I were to teach a chimpanzee the order of arabic numerals, by using a computer with a touch screen and a reward deliverer interface, my program would first display the numerals in a fully ordered fashion that is easily followed even by humans, which are surprisingly inferior to chimpanzees in this exercise. For example, in a horizontal line from left to right in a strictly ascending order, if touched sequentia...