Multi-Disciplinary Paths to Actor-Centric Non-Player Character Emotion Models

Introduction

“Constructing characters” is a phrase that infers distinct meanings for two participants in the creative process of computer-based media. On one hand, for the narrative architect of video games or other kinds of narrative computational media, it is a semiotic process of fiction authoring where the character designer provides a written personal history. Three-dimensional or two-dimensional models of anthropomorphic shape combined with voice can also suggest agency in a game space. A weapon-wielding muscular humanoid with big bright eyes is well equipped for video game combat and all of the emotional expression players associate with fighting. Once audio-visual elements are programmed to react to user input, these elements can signify to the observant player an imagined persona. On the other hand, for the developer of video game computer code, “constructing characters” is a process of designing a system that uses quantitative data derived from the game program, the computer operating system or from player input data to control or trigger character animation and voicing such that the player experiences the presence of a seemingly intelligent cohesive character identity. The result of the work of the designer and the developer is a composite signified that evolves in the player’s mind over the time of game play.

The manner of construction for narrative architects of video games depends on mental processes of player participation. Over the course of game play time, the player may observe actions and behaviors of Non-Player Characters (NPCs) so that a pre-game play biography and an in-game “alterbiography” (Calleja 2009) combines the NPC’s pre-game past with the evolving NPC actions the player witnesses or learns through game interaction since the start of the game. The manner of character construction for video game developers depends on computer languages whose frameworks contain data structures (primitives, classes, objects) and data behaviors (methods, functions) that can trigger and manipulate unique animations of the three-dimensional mesh model and its sound emanations (usually a voice) in ways that resemble the player’s understanding of human and animal emotional expressions. These NPC animations and sounds must be recognizable by the player as specific to the NPC’s type as a fictional narrative agent (human or non-human) and consistent with the character’s role within the world of the game.

The study of character construction coincides with the related research in other disciplines. The late twentieth century coincidentally delivered strains of thought from disciplines that sought to provide taxonomies of two human endeavors – storytelling and emotion expression. Narratology addressed the former and evolved from literary theory and folklore studies to describe systematically the human perception and representation of stories in various media. The categorization of characters within stories based on a typology of roles and emotion sets afforded to those roles is one specialization within narratology. Cognitive psychology and its subdiscipline, Computational Cognitive Psychology, evolved as a reaction to Behaviorism and as an alternative explanation to the mental and emotional processes that drive human behavior. The categorization of human emotions as well as their neurological processes is one subdiscipline that Cognitive psychologist frequently consider. The two disciplines converge in computer game design because game character designers and game code developers both use models from which characters can be efficiently produced. These characters and their behaviors can be embodied as preconfigured audio-visual animation and sound synthesis systems for “static” characters or can be used in-game to spawn procedurally generated characters or behaviors.