# 📝Hick’s law

The law says that the mean reaction time is linear function of the mean entropy. Entropy growths logarithmically with the number of choices available.

$RT = a + b * log_2 (n + 1)$

where

$RT$ is reaction time

$log_2 (n + 1)$ is mean entropy

$a$ and $b$ are coefficients (should be found empirically for each case)

Hick’s law is about choice reaction time,

*not decision time*as is commonly thought.The law presumes that correct answer is known and is not something that should be thought about or discovered. (Subjects undertook a training before running the experiment.)

The law is not universal. There are many situation when it does not apply.