The
GNS Theory, as originally developed by
Ron Edwards, is a relatively amorphous body of work attempting to create a
theory of how
role-playing games work. Primarily, GNS Theory holds that participants in role-playing games reinforce each other's behaviour towards ends which can be divided into three categories:
Gamist,
Narrativist and
Simulationist.
Strictly, GNS theory is concerned with players' social interactions, but it has been extrapolated to direct
game design, both in and outside the world of RPGs. A game can be classified according to how strongly it encourages or facilitates players reinforcing behaviours matching each category. Game designers find it useful because it can be used to explain why players play certain games.
Ron Edwards later discarded GNS Theory in favor of
The Big Model, which includes the GNS categories as different kinds of creative agenda.