Typically people don't see a gray area when it comes to numbers; you either get them or you don't. But new research says our brains are actually systematically designed to handle numerals.
According to Scientific American, humans inherently look at numbers and file them in a mental "number line"—with one side of the brain "responding to small numbers, the adjacent region to larger numbers, and so on, with numeric representations increasing to the far end."
Consider the instance where you are checking out of the supermarket in the "15 items or less" lane and the woman in front of you has a hefty cart of groceries containing way more than allotted for the speedy check-out line. Without counting, you have determined that this woman's groceries surpass 15 and the approach to ascertaining that conclusion utilized a numeric map in your brain. In essence, you have perceived numerosity using a numeric brain map, which is the foundation for your arithmetic skills.
Researchers concluded that our numerical deduction skills are comparable to the way we process senses: Previous studies have shown that humans absorb visual or auditory features and organize them topographically. And while we may process numbers and sensory input similarly, separate parts of the brain are enlisted for arithmetic functions, which are language-dependent. Quantity-based judgments like the ones explored in the "number line" theory are language-independent, which has led researchers to conclude that our numeric consumption may be as innate as hearing.
The stipulation that our brains map abstract information is not necessarily new. But it does open the dam on the unquantifiable maps that may actually be hidden in our brains.