لطفا منتظر باشید ...
Positive and Negative Basketball
To bring this abstract discussion closer to game design, let's look at several game examples. In his talk "Feedback Systems and the Dramatic Structure of Competition," LeBlanc invented two variations on the formal structure of Basketball: Positive Feedback Basketball and Negative Feedback Basketball. Each variation adds just a single rule on top of the existing formal structure of the game:
Negative Feedback Basketball: For every N points of difference in the two teams' scores, the losing team may have an extra player in play. Positive Feedback Basketball: For every N points of difference in the two teams' scores, the winning team may have an extra player in play. How do the addition of these rules change the game? Say, for example, that N is 5. In a game of Negative Feedback Basketball, when Team A fell behind by 5 points, it would gain a player on the court and begin to play with a team of 6. As soon as Team A scored points that put it behind by less than 5, it would drop its extra player. On the other hand, if Team A continued to do poorly, when its score was 10 points behind the other team, it would gain a second extra player. Why is this an example of negative feedback? Because the adjustments in the system (gaining and losing players) encourage the system to move toward a stable, steady state. A losing team gets extra players, which helps it catch up to the winning team; when it moves to within 5 points, the two teams are evenly matched. The steady state of this system is not that the total points tend towards zero, but that the difference between the two teams' scores stays near zero. The end result is that Negative Feedback Basketball games would tend to be very close games. Positive Feedback Basketball creates the opposite situation. As soon as one team increased its lead, it would gain additional players. These new players would help the team do even better against the opposing team, which would increase the winning team's lead even more, which would result in yet more players for that team. Eventually, the court would be absurdly crowded with members of one team, who would completely overwhelm and defeat the team with only five players. Positive Feedback Basketball encourages a large difference between the two teams' scores, so that there is a runaway, devastating victory instead of a closely matched game. As in the examples of heating and cooling, there are many ways to transform the game system. We could, for example, change the rules to remove players instead of adding them. In this case, in Negative Feedback Basketball, when one team pulls ahead by N points, it would lose a player, making it easier for the other team to catch up. In Positive Feedback Basketball, the team that was behind by N points would lose a player, encouraging them to fall further behind, which would result in the loss of even more players. Eventually, one team would fall so far behind that none of its players would be left on the court. In both games, even though players are removed rather than added, the end results remain the same: Negative Feedback Basketball tends toward stable, close matches and Positive Feedback Basketball tends toward unstable, unbalanced matches. Each variation on the game of Basketball would result in vastly different player and spectator experiences. Yet all we did was add one rule that affected the behavior of the system. Feedback systems offer game designers a powerful tool to affect a game's formal structure and the way that structure manifests in play.
