 Is the analog system species universal? If this analog numerical system is innate, it should be found in all human societies, no matter how urban or rural, educated or unschooled, whether in technologically advanced societies or remote and isolated tribal villages in other parts of the  world.[23] If it is the same system evident in the youngest infants, it should not require exposure to any symbolic representations of number, such as Arabic numerals or a number lexicon. To test this hypothesis, investigators explored the analog number system in the Amazonian Munduruku people, an isolated tribe whose language has no words for numbers greater than 5. As predicted, the Munduruku compared and added large approximate numbers far beyond their naming range. Moreover, performance decreased as the ratios decreased, just as it did in a group of French control subjects (Dehaene et al. 2008).