Geometry in the Amazon

Geometry in the Amazon

Humans are apparently born with the ability to grasp geometrical concepts, say researchers who tested an indigenous group of people called the Mundurukú, who live in the Amazon. Their findings were reported in the January 20, 2006 issue of Science.

Stanislas Dehaene of the Collège de France led the research effort. He and his team tested 14 Mundurukú children and 30 adults. They then compared their findings against test results of American children and adults. To test the subjects, Dehaene's team designed arrays of six images, five of which were the same. One image varied slightly. Participants were asked, in their own language, to identify which one didn't belong or looked “weird” or “ugly.” It turned out that even six-year-olds scored above what would be expected by chance. The average score was nearly 67 per cent — the same as American children. American adults performed better, which seems to lend credence to the idea that formal education enhances understanding.

These results imply that geometrical concepts are universal across humanity, with cultural factors such as maps or language enriching understanding, the researchers said. “The spontaneous understanding of geometrical concepts and maps by this remote human community provides evidence that core geometrical knowledge, like basic arithmetic, is a universal constituent of the human mind,” the study's authors said. The Mundurukú children and adults, living along the Cururu River in the Amazon region of Brazil, “made use of basic geometric concepts such as points, lines, parallelism, or right angles to detect intruders in simple pictures,” the researchers concluded.

Dehaene and his coworkers had previously investigated the arithmetical abilities of the Mundurukú. Their studies suggested that without language it is difficult to develop a sense for numbers above 3 or 4, in agreement with earlier studies by linguist Daniel Everett with another tribe, the Pirahã. Everett describes Dehaene's new results as “very significant,” but cautions that one must be careful about their interpretation. Other scholars are more skeptical.

Dehaene is the author of The Number Sense, a study of “how the mind creates mathematics” that argues that mathematics is to some extent “hardwired” in the human brain.