Wizard of Oz: bringing drama to virtual reality

Science News, Dec 19, 1992 by Ivars Peterson

When Dorothy steps out of her drab, cyclone-tossed farmhouse into the glowing Technicolor landscape of Munchkinland, she brings with her not only her dog Toto, but also the film's entranced audience. Captivated by a compelling story and vivid characters, viewers of "The Wizard of Oz" willingly surrender themselves to the fantastic world through which Dorothy and her companions travel.

Now imagine yourself participating in the adventure - skipping down the yellow brick road with Dorothy, conversing with the Scarecrow, sparring with the Cowardly Lion, confronting the Wicked Witch of the West in her castle - and influencing the action.

Such is the promise of new forms of entertainment that rely on computers to create interactive, simulated worlds.

With the technology for generating these microworlds still at a rudimentary stage, most researchers have concentrated on such technical matters as making the required paraphernalia-goggles, instrumented gloves, video screens less intrusive and on integrating the hardware so it functions seamlessly. These efforts have produced systems that allow users to play interactive games, "stroll" through virtual buildings, and wage war across simulated battlefields (SN: 1/4/92, p. 8).

But that's not enough for computer scientist Joseph L. Bates, who heads the Oz project at Carnegie Mellon University in Pittsburgh. Bates wants to learn how to build convincing characters to populate these computer-mediated worlds. He wants to develop software that authors can use to fashion rich, dramatic frameworks for guiding the activities of both user and fictitious character.

"To me, the interesting part is not the interface question of how you present something in three dimensions and so on," Bates says. "Well-written books do a wonderful job of projecting you into a fantasy world. It's really a question 01 the quality of the characters and the quality and style of the story that goes into the presentation."

In Bates' view, the denizens of artificial worlds must themselves be active. "They have to do things, and in order to do things, they need to know what to do:' he contends. "We have to build in enough of a mind to convince a user who's interacting with the character that it's alive and complex."

To explore these issues, Bates has gathered together a research group comprising faculty and students in computer science, drama, and English. "It's a great mixing of the arts and science," he notes. "It involves psychology, it involves art, it involves computing."

At the Oz project's core lies the notion of applying and integrating what researchers in artificial intelligence (AI) have learned about developing software that can represent emotions, formulate goals, direct behavior, and understand language. "We have here microworlds that are artistically interesting:' Bates says. "This is an area in which some of the goals of AI can be achieved without having the complications of the real world."

Lyotard, a temperamental house cat, lives in a computer. The only readily apence of its existence is the printed text that appears on a computer screen.

Bates, graduate student A. Bryan Loyall, and their co-workers created this simulated cat, who inhabits a virtual apartment, as part of an experiment in "interactive fiction." They sought to construct a creature that reacts convincingly enough to persuade any person invading its territory that it's a real cat.

Cat owners in the research group furnished a catalog of feline behavior on which to base the simulation. Software linked these characteristic behaviors to representations of such emotions as anger, fear, hope, sadness, dislike, happiness, and gratitude.

The story itself concerns the cat's behavior in the absence of its new owner when a visitor comes to the apartment. What happens depends on how the cat is feeling and on what you, as the visitor, key into the computer. In response to these typed stimuli, Lyotard senses, thinks, then acts. The result appears as text on the computer screen.

Despite its complete dependence on text, this simulation can be remarkably engrossing. Users report spending lengthy periods trying to get Lyotard to come out of hiding or to nibble on a snack.

This success emphasizes that simulated beings don't have to be especially smart, and they don't have to reside in a realistic, three-dimensional environment for a user to suspend disbelief. "Just as in a good film, it's usually not the scenery although it's nice to have good scenery - but the character or story that's at the film's core," Bates notes.

Nor do characters have to be overly complex. Indeed, a simulated creature that keeps quiet most of the time can appear quite knowing. It takes advantage of a human tendency to attribute subtlety, understanding, and emotion to such subdued behavior - so long as the creature doesn't actively destroy this illusion by doing something patently dumb or unrealistic.

Good novelists have numerous literary devices at their disposal for carrying readers through the twists and turns of a plot to a thrilling and satisfying conclusion. But what can the author of a free-running dramatic simulation do in the much more delicate situation of shaping the experience of a user apparently free to interact with the fictitious characters?