Do you know that our brain works logarithmically?

1. Do this exercise:
   • Draw a number line
   • Mark $0$ and $1,000,000,000$ on the line.
   • Ask yourself a question: where is $1,000$?
2. Many people put $1,000$ at the $1/3$ position. Note that $1,000=10^3$, $1,000,000,000=10^9$, where $9$ is triple of $3$. This implies that we perceive number logarithmically!
3. Not only size of a number, but also weight of an object, loudness of a sound, brightness of a star, spiciness of a chili, all of these are perceived logarithmically by the human brain.
4. Such logarithmic law is known more than 100 years ago, under the name “Weber-Fechner law” in psychophysics.