Page 250 - Socially Intelligent Agents Creating Relationships with Computers and Robots

The Cooperative Contract 233

To support this mediation we are developing a system that sits behind the
scenes of a computer game engine, directing the unfolding action while moni-
toring and reacting to all user activity. The system, called Mimesis[6], uses the
following components:
1. A declarative representation for action within the environment. This may
appear in the type of annotations to virtual worlds suggested by Doyle and
Hayes-Roth [4], specifically targeted at the representational level required to
piece together plot using plan-based techniques described below.
2. A program that can use this representation to create, modify and main-
tain a narrative plan, a description of a narrative-structured action sequence that
defines all the activity within the game. The narrative plan represents the activi-
ties of users, system-controlled agents and the environment itself. This program
consists of two parts: an AI planning algorithm such as Longbow [7] and an
execution-management component. The planning algorithm constructs plans
for user and system interaction that contain such interesting and compelling
narrative structure as rising action, balanced conflict between protagonist and
antagonist, suspense and foreshadowing. The execution manager issues direc-
tives for action to the system’s own resources (e.g., the story’s system-controlled
characters), detects user activities that deviate from the planned narrative and
makes real-time decisions about the appropriate system response to such de-
viations. The response might take the form of re-planning the narrative by
modifying the as-yet-unexperienced portions of the narrative plan, or it might
take the form of system intervention in the virtual world by preventing the user’s
deviation from the current plan structure.
3. A theory capable of characterizing plans based on their narrative aspects.
This theory informs the program, guiding the construction of plans whose lo-
cal and global structure are mapped into the narrative structures of conflict,
suspense, etc.

4. Conclusions
People interact with systems such as computer games by using many of
the same social and communicative conventions that are seen in interactions
between people [8]. I propose that expectations about collaboration between
computer game players and game systems (or their designers) that licenses both
thegameplayers’andthegamedesigners’understandingofwhatcomponentsof
thegame mean. Consequently, theco-operativenature of the gamingexperience
sets expectations for the behavior of both the game and its players. As computer
and console games become more story-oriented and interactivity within these
games becomes more sophisticated, this co-operative contract between game
and user will become even more central to the enjoyment of a game experience.