Everyone maps numbers in space. But why don’t we all use the same directions? | Science News
Consider a ruler, a timeline or even weights lined up in a gym. Why are the smaller values, the earlier times and the lighter weights typically on the left and the larger or later values on the right?
Since at least the early 1990s, researchers have debated whether these mental number lines, or the tendency to order numerically from left to right, are innate or learned. In more recent years, this debate has broadened from mental number lines to mental magnitude lines: the human tendency to map any abstract idea, such as numbers, time and even facial expressions, in three-dimensional space. Now, an August 11 study in Science Advances, comparing mostly adult Indigenous farmer-foragers in Bolivia to U.S. preschoolers and adults has fallen squarely on the learning or culture side, adding fresh fuel to the debate.