Counting systems and the Pirahã tribe

One of the central questions in language is of linguistic determinism. Language is an important component of one’s ability to comprehend numbers and quantities. Counting takes many forms depending on culture. Researchers have not yet found a language that does not represent numbers. Some cultures use body parts to count or forms of recursion using a small numerical base. Gumulgal South Sea Islanders count utilizing a recursive binary system. The Pirahã are a monolingual population (< 200 population) that have rejected assimilation with the Brazilian culture. A predominantly hunter-gatherer population, the Pirahã live in villages of between 10 and 20 people on the banks of the Maici River in Brazil’s Lowland Amazonia region. The Pirahã counting system consists of what is termed the “one-two-many” system. Quantities beyond two are described as many, in this system of counting.

A researcher visited the Pirahã tribe to test the impact of counting systems on the ability to estimate quantity. Members of the Pirahã tribe were given a visual counting task to test the impact of numerical systems on visual estimation. Each tribe member was allowed to inspect a group of nuts for a few seconds. The nuts were placed in an opaque can, so the quantity could not be viewed. For each trial, a nut was removed from the can, and the tribe member was asked to tell the researcher if the can still contained nuts. Tribe members who were able to estimate the quantity of nuts in the can would be able to tell when there were none left. Figure 1 shows the proportion of correct responses averaged for each target number of nuts over all trials.

Figure 1: Results for the Pirahã tribe members’ trials averaged for each target number (n = 63). For each trial, each tribe member estimated the number of nuts left in the can (target). The proportion of correct responses is shown (the first and last nut were excluded).