How we think about numbers

In the introductory chapter of his book, Bellos talks about how numbers are conceived in our minds and whether or not math is a cultural or intrinsic skill. By studying a remote tribe in the amazon, he concluded that we naturally think about numbers logarithmically not linearly. Here's an example. Members of this tribe that could only count to 5 were shown dots on a screen from one dot to 10. They were then asked to place them on the line where they saw fit. if someone from western civilization were asked to do this they would more than likely space the dots evenly along the line because this is the way we've been taught through rulers, tape measurers etc. Members of this trube though were much more inclined to put half as much space between 3 and s as they did between 2 and 1. Similarly between 4 and 3 was half as long as between 3 and 2. He concludes from this that we innately think about numbers as ratios. 2 dots is twice as big as one dot, but 3 dots is 1.5 times bigger than 2.