Can a knowledge of numbers determine the way we think?© AlamyA study of an Amazonian tribe is stoking fierce debate about whether people can count without numbers.
Psychologists, anthropologists and linguists have long wondered whether animals, young children or certain cultures can conceptualize numbers without the language to describe them.
To tackle the issue, behavioural researcher Peter Gordon of Columbia University in New York journeyed into the Amazon. He carried out studies with the Pirahã tribe, a hunter-gatherer group of about 200 people, whose counting system consists of words which mean, approximately, 'one', 'two' and 'many'.
Gordon designed a series of tasks to examine whether tribe members could precisely count and conceive of numbers beyond one or two, even if they lacked the words. For example, he asked them to look at a group of batteries and line up a matching amount.
The tribe members struggled to perform these tasks accurately after the numbers were greater than three, Gordon reports in Science1; and their performance got worse the higher the numbers climbed. "They couldn't keep track at all," he says.
Opposing views
Other researchers in the field have welcomed the study. But they disagree about what it means. Psychologist Charles Gallistel, at Rutgers University in Piscataway, New Jersey, says that the Pirahã simply may not recognize when one quantity of items exactly equals another, so they have trouble with matching tasks. He argues that people do possess an innate, non-verbal ability to conceive of all numbers, and that language simply helps them to refine it.
Psychologist Susan Carey of Harvard University in Massachusetts argues the opposite: she says we lack an innate ability to count beyond very small numbers, and that the Pirahã difficulty with numbers proves it. "It's a spectacular finding," she says.
Carey and other researchers believe that children and some animals are born with two basic types of 'counting' but that these are limited. First, they can recognize one, two or three objects by recording an image in their memory. Second, they can make estimates of larger numbers, such as 'about twenty'. Carey believes that the Pirahã rely on these innate systems.
Whorf hypothesis
On a broader level, the study also addresses a long standing and controversial hypothesis developed by Benjamin Lee Whorf in the late 1930s: that language can determine the way we think or what we are able to think.
But Gordon's study is one of the best examples in which language allows people to think something completely new, says cognitive psychologist Lisa Feigenson of Johns Hopkins University in Baltimore, Maryland. "This is by far the strongest piece of evidence," she says. In this case, a lack of language seems to prevent the Pirahã from thinking about larger numbers, she says.
However, the latest study will not resolve the debate about whether language can shape thought in other examples, points out Feigenson. "I think the jury is still out," she says.
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