Pen-and-paper role-playing games typically involve a player called the gamemaster (or GM for short) who can dynamically create the story, setting, and rules, and react to a player's choices.[8] In role-playing video games, the computer performs the function of the gamemaster. This offers the player a smaller set of possible actions, since computers can't engage in imaginative acting comparable to a skilled human gamemaster. In exchange, the typical role-playing video game may have storyline branches, user interfaces, and stylized cutscenes and gameplay to offer a more direct storytelling mechanism. Characterization of non-player characters in video games is often handled using a dialog tree. Saying the right things to the right non-player characters will elicit useful information for the player, and may even result in other rewards such as items or experience, as well as opening up possible storyline branches. Multiplayer online role-playing games can offer an exception to this contrast by allowing human interaction among multiple players and in some cases enabling a player to perform the role of a gamemaster.[3][9]