Difference between revisions of "Agents"

Revision as of 09:46, 9 January 2011

Game elements that can be interpreted as having goals.

Games can be viewed as simulations, i.e. an imitation of some aspect of reality. While these may overlook other aspects and include fantastical elements, games often include representations of Agents that actively work towards goals through manipulating the game environment. These Agents may be the points through which player can interact with the game or be the conduits for game facilitators or separated sets of rules to enact other inhabitants in the game world.

Examples

While the ghosts of Pac-Man and the alien of Space Invaders can kill the player they do not actively react to what the player does^[1][2]. In this they show little evidence for agency. In contrast, the enemies in later games such as Braid, Gauntlet, the Doom series, the Left 4 Dead series, and the Super Mario series, adjust their actions in response to player actions. This is typically enhanced by them going from passive modes to active modes when first detecting the players.

Players' characters in roleplaying games such as Dungeons & Dragons and GURPS are examples of Agents since enacting or saying what the characters do is the way they can affect the game world. Likewise, all the non-player characters and monster controlled by game masters are Agents.

The computer programs underlying Façade and ELIZA give rise to characters that can be experienced as having personal goals and emotional states, and exploring these is the prime intention of the designs.

Using the pattern

The presence of humans controlling Avatars or Units in games makes it nearly impossible to avoid have Agents in games, and one could argue that unless human-controlled Agents exist in the design it is not a game. The description of Crobots, P-Robots, etc., as games show that others argue that this is not necessary. Adding the Roleplaying pattern (which indeed players themselves can do as a form of Meta Game to most games) is an explicit way of advocating that game elements should be controlled as if they had their own goals - if this is not done the players can be said to not be Roleplaying.

Avatars, Characters and Units are examples of how Agents can be created by being directed by humans (or only seem to be so due to actually being Mules or AI Players). NPCs and Units controlled by Algorithmic Agents or Game Masters are examples of other common types of Agents.

Agents as a pattern are often volatile, that is players tend to rationalize them to simpler mental constructs if possible (typically Converters, Containers, Obstacles, Self-Service Kiosks or Traps)^[3]. This in practice means that they are perceived as game elements which move and act with Predictable Consequences and where one doesn't have to assume they have intentional goals. The use of Game Masters, and for Multiplayer Games other players, can make it impossible to reduce Agents behavior to a set of rules since the people controlling them can have an Unpredictable Behavior, at least as long as the Game Masters and players aren't simply following a set of rules (they may not have an option unless the game has a Freedom of Choice or Randomness). For Agents built on Algorithmic Agents giving them Unpredictable Behavior is somewhat of a paradox since they are a set of rules fundamentally but several tricks exists, including Ambiguous Responses, Emotional Attachment, Own Agenda, and Randomness.

Since Agents can have Opposing Goals to each other it is possible to create Enemies through the use of this pattern, and this is necessary to create Conflict in games since this requires at least two opposing parties. Even if Enemies do not have to be built upon Agents (they can display their hostility primarily through their diegetic presentations), unless players perceive their Enemies as having agency the gameplay will more likely be interpreted as Maneuvering or Puzzle Solving than Conflict. Agents can of course also be used to support Cooperation, e.g. through providing Companions of team mates in Teams. By using Agents for Conflict or Cooperation game designers can create and modulate Challenging Gameplay, although they may also wish to have Difficulty Settings, Dynamic Difficulty Adjustment and Handicap Systems so that it can be adjusted for individual game sessions.

In Single-Player Games it is easy for players to forget to differentiate between their own goals and that of which the Focus Loci they are controlling. Characters can be used to provide an explicit statement of the goals of diegetic people and thereby promote Roleplaying which in turn makes the player act according to the Characters goals. Quests are especially suitable in this context, since they provide a way to make the goals of the Characters into both diegetic and gameplay concepts. This is most easily achieved in games where one controls Avatars (e.g. the Fallout series), but the makers of the Europa Universalis series suggest that players can Roleplaying historical countries.

Some games are designed to allow the change of whom or what is controlling Agents. One example of this is Drop-In/Drop-Out games where that do not add or remove Avatars when people enter and exit but instead shift control between these and Algorithmic Agents. Another is when Game Masters take control of Player Characters due to them losing their self-control, e.g. when failing sanity checks in the Roleplaying game Call of Cthulhu. Games with Public Interfaces open up for players to switch between themselves or play simultaneously without the game system being able to detect this. In other cases, players willing give up some of their control to Aimbots^[4] to achieve better results.

Diegetic Aspects

That Agents visually appear as being capable of thought and self-controlled actions is a first step to making players and Spectators approach a game element as something possessing intentionality and agency. Fortunately, this is quick easy to do since humans are prone to anthropomorphize, allowing for example zombies (the Left 4 Dead series), robots (Crobots), Lego figures enacting movie characters (Lego Star Wars series), and ball of tars (Gish) to be viewed as Agents.

To maintain Diegetic Consistency it may be required to have Enforced Agent Behavior. This can be encoded in the rules of Algorithmic Agents easily or delegated to Dedicated Game Facilitators such as Game Masters for the control of NPCs (Enemies typically have such a Limited Set of Actions that they cannot break the Diegetic Consistency). Game Masters can also ensure that Player Characters act believably as part of their role in setting up and running Self-Facilitated Games.

Interface Aspects

It is quite self-evident that Agents controlled by humans need to consider how they should be able to initiate all the possible actions the Agents can do through their own actions using an interface. Somewhat less obvious is that games using Quests to provide Character goals may need Secondary Interfaces if a multitude of them are being undertaken at the same time.

Narrative Aspects

Agents are a vital component of any Narration Structure since they provide anchors for Emotional Attachment and the sources of Conflict. As such Agents need to be designed in conjunction with a game Narration Structures.

Consequences

Since Agents require players to consider what the Agents will do next, they promote Stimulated Planning. They can be used to create Conflict, and when so used they typically also provide Tension since the players perceive that forces are working against them.

Agents created by having players control them are Focus Loci.

Relations

Can Instantiate

Challenging Gameplay, Cooperation, Emotional Attachment, Focus Loci, Multiplayer Games, Stimulated Planning, Teams, Tension

with Enemies

Conflict

with Opposing Goals

Enemies

Can Modulate

Challenging Gameplay, Narration Structures, Non-Player Characters, Spectators, Units

Can Be Instantiated By

AI Players, Algorithmic Agents, Avatars, Characters, Companions, Dedicated Game Facilitators, Game Masters, Humans, Mules, Roleplaying

Can Be Modulated By

Ambiguous Responses, Drop-In/Drop-Out, Emotional Attachment, Enforced Agent Behavior, Opposing Goals, Own Agenda, Quests, Public Interfaces, Randomness, Roleplaying, Unpredictable Behavior

Possible Closure Effects

Converters, Containers, Maneuvering, Obstacles, Predictable Consequences, Puzzle Solving, Self-Service Kiosks, Traps

Potentially Conflicting With

-

History

New pattern created in this wiki.

References

1. ↑ Enemies section in the Wikipedia entry for Pac-Man.
2. ↑ Wikipedia entry for Space Invaders.
3. ↑ Lankoski, P. & Björk, S. (2007). Gameplay Design Patterns for Believable Non-Player Characters. DiGRA 2007 Conference.
4. ↑ Wikipedia entry for Aimbots.

Acknowledgments