Directed Improvisation by Computer Characters

Barbara Hayes Roth, Stanford Knowledge Systems Laboratory

Seminar on People, Computers, and Design
Stanford University February 3, 1995


"Directed improvisation" is a paradigm for human-computer interaction. Directors (who may be human users or other computer programs) guide the behavior of computer characters with abstract instructions that establish skeletal narrative structures and weak constraints on the desired behaviors. The characters work together to improvise a course of behavior that conforms to the structure, meets the constraints, and achieves other performance objectives. Thus, characters follow directions, but may also enhance performance, while surprising and engaging users with their improvisations along the way.

Directed improvisation is similar in spirit to previous work on instructable agents, multi-agent systems, advanced programming languages, and object-oriented simulation. Following this earlier work, directed improvisation aims to employ more abstract directions to guide more discretionary behavior by more complete computer characters.

We believe that computer characters capable of performing directed improvisation will be useful elements of diverse applications, especially applications in education, the arts, and entertainment. We are developing a technology that combines a supporting agent architecture with configurable components to facilitate efficient and economical development of a variety of specific characters for different applications. Our approach incoporates media-independent interfaces, so that a given character's "mind" can be embodied in animation, virutal reality, text, or other media.

Our current testbed application is a "virtual theater," in which animated characters take direction to improvise episodes of physical and verbal behaviors. To be effective, the characters also must exhibit simple intelligence, life-like qualities, and improvisational expertise. Within the virtual theater, we conceive several specific modes of interaction: animated puppets, animated actors, collaborative playcrafting, improv troupe, improv direction, and interactive story. In all of these modes, directed improvisation offers users (in our case, children) the combined pleasures of directing the creation, re-telling, or re-experiencing of a story, while being delighted by the characters' unpredictable improvisations within the story structure. In addition to its use as an experimental testbed, the virtual theater is a promising paradigm for several kinds of commercial applications: experience-based learning environments, new kinds of computer games, a new medium for artistic self-expression, or a new form for interactive story experience.


Barbara Hayes-Roth has been Senior Research Scientist in Computer Science at Stanford since 1982. Previously, she was Senior Computer Scientist at the Rand Corporation and Member of Technical Staff at Bell Laboratories. She holds BA (1971, Boston University), MS (1973, University of Michigan), and PhD (1974, University of Michigan) degrees in Cognitive Psycholgy. Dr. Hayes-Roth developed the "dynamic control architecture" (embodied in the BB1 software), which supports the development of computer agents that explicitly reason about, plan, and control their own behavior in response to run-time conditions. Dr. Hayes-Roth has collaborated with domain experts to develop experimental agents for: modeling protein structures, designing construction site layouts, monitoring medical patients, monitoring plant control and manufacturing equipment, controlling autonomous robots, and more recently, controlling improvisational computer characters. She has published over 100 scientific articles and is a former Councillor, current Conference Chair, and a Fellow of the AAAI.


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