An Amazonian language with only 300 speakers has no word to express the concept of "one" or any other specific number, according to a new study from an MIT-led team.

The team, led by MIT professor of brain and cognitive sciences Edward Gibson, found that members of the Piraha tribe in remote northwestern Brazil use language to express relative quantities such as "some" and "more," but not precise numbers.

It is often assumed that counting is an innate part of human cognition, said Gibson, "but here is a group that does not count. They could learn, but it's not useful in their culture, so they've never picked it up."

The study, which appeared in the June 10 online edition of the journal Cognition, offers evidence that number words are a concept invented by human cultures as they are needed, and not an inherent part of language, Gibson said.

The work builds on a study published in 2004, which found that the Piraha had words to express the quantities "one," "two," and "many." The MIT researchers observed the same phenomenon when they asked Piraha speakers to describe sets of objects as they were added, from one to 10.

However, the MIT team decided to add a new twist--they started with 10 objects and asked the tribe members to count down. In that experiment, the tribe members used the word previously thought to mean "two" when as many as five or six objects were present, and they used the word for "one" for any quantity between one and four.

This indicates that "these aren't counting numbers at all," said Gibson. "They're signifying relative quantities."

He said this type of counting strategy has never been observed before, although it may also be found in other languages believed to have "one," "two," and "many" counting words.

The paper is part of a larger project that investigates the relationship between Piraha culture and their cognition and language, testing some claims by Daniel Everett, a linguist at Illinois State University, in a 2005 issue of Current Anthropology.

One other discovery of the project is that the Piraha can perform exact matching tasks as long as there is no memory component to them, but once there is a memory component, they approximate their matches. This suggests that language is a cognitive technology that aids humans in memory tasks.

Lead author of the paper is Michael Frank, a graduate student in Gibson's lab. Other authors are Evelina Fedorenko, a postdoctoral associate at the McGovern Institute for Brain Research at MIT, and Everett.

