Avoid Pronoun Principle

Avoid Pronoun Principle is a principle which states: 'Avoid Pronoun'. This principle, which is considered a subcase of a conversational principle ('don't say more than is required'), is invoked to impose a choice of PRO over an overt pronoun where possible.

Example
This principle explains why his in the sentence does not refer to John, unless it is stressed.

John would much prefer his going to the movie.

If the subject of the phrase going to the movie refers to John, the Avoid Pronoun Principle requires PRO as a realization of that subject.

Link
Utrecht Lexicon of Linguistics