Simultaneous action selection
Encyclopedia
Simultaneous action selection, or SAS, is a game mechanic that occurs when players of a game take action (such as moving their pieces) at the same time. An example of a game that uses this type of movement is Diplomacy
. Typically, a "secret yet binding" method of committing to one's move is necessary, so that as players' moves are revealed and implemented, others do not change their moves in light of the new information. Thus, in Diplomacy, players write down their moves and then reveal them simultaneously. Because no player gets the first move, this potentially arbitrary source of advantage is not present. It is also possible for simultaneous movement games to proceed relatively quickly, because players are acting at the same time, rather than waiting for their turn. Simultaneous action selection is easily implemented in card game
s such as Apples to Apples
in which players simply select cards and throw them face-down into the center.
Some games do not lend themselves to simultaneous movement, because one player's move may be prevented by the other player's. For instance, in chess, a move of bishop takes queen would be incompatible with a simultaneous opposing move of queen takes bishop. By contrast, simultaneous movement is possible in Junta
because each coup phase has a movement stage and a separate combat stage; no units are removed until all have had a chance to move. It has been noted that "a certain amount of reverse psychology and reverse-reverse psychology ensues" as players attempt to calculate the implications of others' potential actions. Junta also has simultaneous action selection in that players secretly choose their locations at the same time. This is important in that, for instance, a player plotting an assassination may choose the bank for his or her own location (hoping to quickly deposit the ill-gotten gains) before finding out whether the location of his or her assassination was on the mark.
It has been noted that in games with simultaneous movement, the mathematical combinations are staggering: "Unlike chess
, which has 20 possible opening moves, seven player Diplomacy, with its 'simultaneous' movement, has over four quadrillion possible opening moves."
Simultaneous action selection is used in many real-world applications such as first-price sealed-bid auctions. The fact that no bidder knows what others are planning to bid may provide an incentive to bid high if there is a strong desire to win the auction, which can result in much higher winning bids than if better information were available. The prisoner's dilemma
is another classic example of simultaneous action selection. SAS can also be used to introduce an element of chance, as when rock-paper-scissors
is used to decide a matter.
Diplomacy (game)
Diplomacy is a strategic board game created by Allan B. Calhamer in 1954 and released commercially in 1959. Its main distinctions from most board wargames are its negotiation phases and the absence of dice or other game elements that produce random effects...
. Typically, a "secret yet binding" method of committing to one's move is necessary, so that as players' moves are revealed and implemented, others do not change their moves in light of the new information. Thus, in Diplomacy, players write down their moves and then reveal them simultaneously. Because no player gets the first move, this potentially arbitrary source of advantage is not present. It is also possible for simultaneous movement games to proceed relatively quickly, because players are acting at the same time, rather than waiting for their turn. Simultaneous action selection is easily implemented in card game
Card game
A card game is any game using playing cards as the primary device with which the game is played, be they traditional or game-specific. Countless card games exist, including families of related games...
s such as Apples to Apples
Apples to Apples
Apples to Apples is a party game originally published by Out of the Box Publishing, and now published by Mattel. It is designed for four to ten players and played for 30–60 minutes....
in which players simply select cards and throw them face-down into the center.
Some games do not lend themselves to simultaneous movement, because one player's move may be prevented by the other player's. For instance, in chess, a move of bishop takes queen would be incompatible with a simultaneous opposing move of queen takes bishop. By contrast, simultaneous movement is possible in Junta
Junta (game)
Junta is a board game designed by Vincent Tsao originally published by Capri in 1975, and later published, as of 1985, by West End Games. Players compete as the corrupt power elite families of a fictional parody of a stereotypical banana republic trying to get as much money as possible into their...
because each coup phase has a movement stage and a separate combat stage; no units are removed until all have had a chance to move. It has been noted that "a certain amount of reverse psychology and reverse-reverse psychology ensues" as players attempt to calculate the implications of others' potential actions. Junta also has simultaneous action selection in that players secretly choose their locations at the same time. This is important in that, for instance, a player plotting an assassination may choose the bank for his or her own location (hoping to quickly deposit the ill-gotten gains) before finding out whether the location of his or her assassination was on the mark.
It has been noted that in games with simultaneous movement, the mathematical combinations are staggering: "Unlike chess
Chess
Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...
, which has 20 possible opening moves, seven player Diplomacy, with its 'simultaneous' movement, has over four quadrillion possible opening moves."
Simultaneous action selection is used in many real-world applications such as first-price sealed-bid auctions. The fact that no bidder knows what others are planning to bid may provide an incentive to bid high if there is a strong desire to win the auction, which can result in much higher winning bids than if better information were available. The prisoner's dilemma
Prisoner's dilemma
The prisoner’s dilemma is a canonical example of a game, analyzed in game theory that shows why two individuals might not cooperate, even if it appears that it is in their best interest to do so. It was originally framed by Merrill Flood and Melvin Dresher working at RAND in 1950. Albert W...
is another classic example of simultaneous action selection. SAS can also be used to introduce an element of chance, as when rock-paper-scissors
Rock-paper-scissors
Rock-paper-scissors is a hand game played by two people. The game is also known as roshambo, or another ordering of the three items ....
is used to decide a matter.
External links
- Games using simultaneous action selection, BoardgamegeekBoardGameGeekBoardGameGeek is a website that was founded in January 2000 by Scott Alden and Derk Solko as a resource for the board gaming hobby. The database holds reviews, articles, and session reports for over 45,000 different games, expansions, and designers. BoardGameGeek includes German-style board games,...
. - http://www.boardgamegeek.com/wiki/page/Simultaneous_Action_Selection