Origins of Numerical Competence: Assessment of Number Sense in Pirahã

Principal Investigator: 
Project Overview
Background & Purpose: 

The goal of the project is to understand the cognitive foundations of number by evaluating links among the set of core systems underlying the ability to manipulate sets and quantities. Previous work has identified three distinct systems: (1) a small exact number system; (2) a large approximate number system; and (3) a system for set-based quantification. We investigate these core numerical competence systems and the relationship among them in a unique population in the Brazilian rain forest whose language lacks words for numbers: the Pirahã.


Research will be conducted with two populations: (1) the Pirahã, a small, isolated, monolingual hunter-gatherer group living in the Brazilian province of Amazonas; and (2) English-speaking college students living in the US. The Pirahãs are an ideal test case for investigating the core numerical systems because their language is the first known to have no words for numbers. As a result, they have very little practice with tasks that would rely on the core numerical systems, allowing us to investigate these systems in their “purest” form.

Research Design: 

The project uses a comparative research design and will generate evidence that is causal [experimental]. This project collects original data from the Pirahã tribe in Brazil and from US college students using a series of behavioral cognitive studies assessing numerical competence (and other abilities for control purposes). In these studies, participants will be presented with different kinds of stimuli, visually (such as real objects, pictures or visual displays on a computer screen) or auditorily (such as words or sequences of musical tones). Participants will be asked to perform a task on these stimuli by either providing a verbal response (e.g., saying whether two displays are identical or not) or a manual response (e.g., pointing to the larger object or set). In each of these tasks, a participant will be tested individually in a quiet space by one or more experimenters. Practice trials will always be provided. Each task will last between 5 and 30 minutes.

Standard statistical analysis tools will be used, such as t-test, ANOVA, regressions, etc.


Findings will be posted as they become available.

Publications & Presentations: 

Frank, M. C., Everett, D. L., Fedorenko, E., and Gibson, E. (2008). Number as a cognitive technology: Evidence from Pirahã language and cognition. Cognition, 108:819-824.

Frank, M. C., Fedorenko, E., and Gibson, E. (2008). Language as a cognitive
technology: English speakers match like Pirahã when you don’t let them count. Paper presented at the 30th Annual Meeting of the Cognitive Science Society.

Target Population: 
Research Design: 


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