Does simple arithmetic give you sweaty palms? Do you always show up late for appointments? Is it a nightmare to figure out the bill at restaurants? If so, you may have dyscalculia, sort of the mathematical version of dyslexia. People with dyscalculia often excel at languages or visual arts, but can barely pass middle school math. They have trouble with numerical concepts—specifically, with associating numerical quantities with their abstract representations. Although it's estimated that about five percent of people have dyscalculia, researchers disagree as to the cause of the disorder. The debate boils down to whether number sense is an innate or learned trait in humans. Some argue that we are born with the ability to understand exact numbers. Even babies, for example, will stare longer when they are shown two dolls moving behind a screen and then three dolls coming out, indicating they were expecting a different numerical outcome. But others argue that the concept of exact numbers is learned, and that we are born with only an "approximate number sense" that allows us to compare different quantities but not necessarily count them. While algebra might be indispensable in the modern world, researchers say an approximate number sense is really all you need to survive in the wild—allowing you to identify, for example, which tree bears more fruit but not the exact quantity. Other studies suggest that our innate sense of numbers isn't linear like a number line, but logarithmic. The Mundurucú people in the Amazon don't use a number system and don't even have words for quantities larger than five. When researchers asked them to place numbers on a number line from 1 to 10, they typically place 3 near the middle and 5 closer to 10. As New Scientist explains:
By the Mundurucú way of thinking, 10 is only twice as big as 5, but 5 is five times as big as 1, so 5 is judged to be closer to 10 than to 1. The team conclude that "the concept of a linear number line appears to be a cultural invention that fails to develop in the absence of formal education". With only limited tools for counting, the Mundurucú fall back on the default mode of thinking about number, the so-called "approximate number system."
For now, dyscalculia as a learning disorder seems to be the more prevailing school of thought. Researchers say that different teaching methods may help those with dyscalculia grasp mathematical concepts. Related Content: DISCOVER: Amazoning Tribe Doesn't Have Words for Numbers DISCOVER: Counting Without Numbers
Image: flickr / Serge Melki