Scientists find Amazonian tribe that has no words to express numbers

Find a much more detailed article here: http://www.newyorker.com/reporting/2007/04/16/070416fa_fact_...

and here: RECURSION AND HUMAN THOUGHT: WHY THE PIRAHÃ DON'T HAVE NUMBERS http://edge.org/3rd_culture/everett07/everett07_index.html