What is least effort principle in science?

This refers to a scientific principle which states that the behaviour of humans follows the path of least resistance. Human languages, for instance, have continuously evolved and become simpler so that users of languages expend minimal effort to use them effectively. The principle was first proposed by American linguist George Kingsley Zipf in Human Behaviour and the Principle of Least Effort as a universal rule that applies to all kinds of behaviour. Among other things, Zipf studied the frequency of the usage of various words in the English language to support his theory.