interactive characters

By Scott Rettberg, 13 December, 2012
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Abstract (in English)

Artificial intelligence methods open up new possibilities in art and entertainment,enabling rich and deeply interactive experiences. At the same time as AI opens up newfields of artistic expression, AI-based art itself becomes a fundamental research agenda,posing and answering novel research questions that would not be raised unless doing AIresearch in the context of art and entertainment. I call this agenda, in which AI researchand art mutually inform each other, Expressive AI. Expressive AI takes seriously theproblem of building intelligences that robustly function outside of the lab, engaginghuman participants in intellectually and aesthetically satisfying interactions, which,hopefully, teach us something about ourselves.This thesis describes a specific AI-based art piece, an interactive drama calledFaçade, and describes the practice of Expressive AI, using Façade, as well as additionalAI-based artwork described in the appendices, as case studies.An interactive drama is a dramatically interesting virtual world inhabited bycomputer-controlled characters, within which the player experiences a story from a firstperson perspective. Over the past decade, there has been a fair amount of research intobelievable agents, that is, autonomous characters exhibiting rich personalities, emotions,and social interactions. There has been comparatively little work, however, exploringhow the local, reactive behavior of believable agents can be integrated with the moreglobal, deliberative nature of a story plot, so as to build interactive, dramatic worlds. Thisthesis presents Façade, the first published interactive drama system that integratescharacter (believable agents), story (drama management) and shallow natural languageprocessing into a complete system. Façade will be publicly released as a free downloadin 2003.In the Façade architecture, the unit of plot/character integration is the dramatic beat.In the theory of dramatic writing, beats are the smallest unit of dramatic action, consistingof a short dialog exchange or small amount of physical action. As architectural entities,beats organize both the procedural knowledge to accomplish the beat’s dramatic action,and the declarative knowledge to sequence the beat in an evolving plot. Instead ofconceiving of the characters as strongly autonomous entities that coordinate toaccomplish dramatic action through purely local decision-making, characters are insteadweakly autonomous – the character’s behavioral repertoire dynamically changes as beatsare sequenced. The Façade architecture includes ABL (A Behavior Language), a newreactive planning language for authoring characters that provides language support forjoint action, and a drama manager consisting of both a language for authoring thedeclarative knowledge associated with beats and a runtime system that dynamicallysequences beats.Façade is a collaboration with independent artist and researcher Andrew Stern.Expressive AI is not the “mere” application of off-the-shelf AI techniques to art andentertainment applications. Rather, Expressive AI is a critical technical practice, a way ofdoing AI research that reflects on the foundations of AI and changes the way AI is done.AI has always been in the business of knowing-by-making, exploring what it means to behuman by building systems. Expressive AI just makes this explicit, combining thethought experiments of the AI researcher with the conceptual and aesthetic experimentsof the artist. As demonstrated through Façade and the other systems/artworks describedin the appendices, combining art and AI, both ways of knowing-by-making, opens upnew research questions, provides a novel perspective on old questions, and enables newmodes of artistic expression. The firm boundary normally separating “art” and “science”is blurred, becoming two components of a single, integrated practice.

(Source: Author's abstract)