The Approximate Number System is How You Count Without Counting

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There's a mechanism in your brain that lets you count without counting. It's called the approximate number system, and it's what lets you know that one line at the grocery store is longer than the other, or that your dining companion's plate has more fries on it than yours.


So Easy A Baby Can Do It

In the scenarios above, you don't actually count the number of people or french fries with words or symbols; you just estimate. This obviously gets harder as the differences get smaller. According to research, you need a 15% difference between two groups of objects in order to accurately distinguish which is larger — that is, 12 versus 14, or 100 versus 115. This system is so innate that even infants can distinguish a difference between quantities, though it starts out much less accurate: six-month-olds need a 2:1 difference, for example.

It Gets Better

This ability does vary from person to person, however, and research has shown that how well you do on tests of the approximate number system correlates with how well you do in math class. You can test how your approximate number system stacks up by taking a free online test like the one on Now research has shown that a person's sense of "approximate number" can be improved, and once that's improved, their math skills can be improved, too. "These findings emphasize the sense in which core cognition, seen across species and across development, serves as a foundation for more sophisticated thought," Lisa Feigenson, a co-author of the study, told "Of course, this raises the question of whether this kind of rapid improvement lasts for any significant duration, and whether it enhances all types of math abilities. We're excited to follow up on these questions."

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What Is The Approximate Number System?

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Key Facts In This Video

  1. One thousands seconds is about 17 minutes, and one million seconds is more than 11 days. 00:53

  2. The word "logarithmic" comes from "arithmos" meaning number, and "logos" meaning ratio. 02:15

  3. Logarithmic thinking and feeling may explain why life may seem to speed up as we get older. 03:50

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