by introducing and describing the setting and the characters. Specific tabletop RPGs may have a unique name for the GM role, for examples: Dungeon Master, Referee and Storyteller. Some games, such as Polaris and Primetime Adventures, have distributed the authority of the GM to different players and to different degrees. This technique is often used to ensure that all players are involved in producing a situation that is interesting and that conflicts of interest suffered by the GM are avoided on a systemic level. The players describe their characters' actions, and the GM responds by describing the outcome of those actions. Usually, these outcomes are determined by the setting and the GM's common sense; most actions are straightforward and immediately successful. For example, if a player has their character look around a room, the GM will describe the room; if they have their character leave, the GM will describe whatever they encounter outside the room. The outcomes of some actions are determined by the rules of the game. For example, while looking around the room, a character may or may not notice an important object or secret doorway, depending on the character's powers of perception. Determining the outcome usually involves rolling dice and adjusting the result for the character's statistics and environmental factors to see whether the action was successful. Typically, the higher the character's score in a particular attribute, the higher their probability of success. There are alternate game systems which are diceless, or use alternate forms of randomization, such as a deck of cards or a Jenga tower. Tabletop RPG settings includes challenges for the player characters to overcome through play, such as traps to be avoided, rulers to be courted, or adversaries to be fought. Many game sessions contain moments of puzzle solving, negotiation, chases, and combat. Frequently, this involves interacting with non-player characters, other denizens of the game world, which are played by the GM. In most games, the full details of the setting are kept secret, but some broad details of the game world are usually given to the players. Tabletop RPGs are often conducted like radio drama: only the spoken component of a role is acted. Acting in tabletop RPGs is not always literal, and players do not always speak exclusively in-character. Instead, players act out their role by deciding and describing what actions their characters will take within the rules of the game.