February 28, 2006

Minstrel, Universe, and the Author

by Noah Wardrip-Fruin · , 2:56 pm

We’ve had quite a bit of writing about literary work using digital computation since the 1990s (e.g., Landow’s Hypertext; Ryan’s Possible Worlds, Artificial Intelligence, and Narrative Theory; Murray’s Hamlet on the Holodeck; Aarseth’s Cybertext). But there’s been surprisingly little written about two story generation systems that got their start in the mid-1980s: Minstrel and Universe. They’ve caught my attention recently, so I’m planning to write two or three posts (after this introductory post) about them. I’ll be contrasting them with the best-known story generator, Tale-Spin — which, if memory serves, is written about in all but one of the books mentioned above.

To us — 30 years after Tale-Spin‘s completion, and outside that context of AI research — Tale-Spin seems strange in its blindness to all but planning. But for understandable reasons the artificial intelligence community did not respond this way to Tale-Spin‘s limitations. After all (as outlined by people like Lucy Suchman and Phil Agre) planning was essentially the only account of intelligent action at that point in AI’s history. Rather, the common diagnosis was that Tale-Spin didn’t make enough plans. Specifically, Tale-Spin was critiqued for only accounting for the plans of characters, and not the plans of authors. The Minstrel and Universe systems sought to address this perceived lack in different ways.

Early publications about the Minstrel and Universe systems appeared in the mid-1980s, and bore a number of similarities. Not only did both emphasize the importance of authorial plans and goals (and cite Natalie Dehn’s 1981 publications about the importance of such goals), they also focused on the importance of then-recent models of how people understand stories. In particular, they focused on Roger Schank’s “Memory Organization Packages” (also called “Memory Organization Points”) and Michael Dyer’s “Thematic Abstraction Units” (also called “Thematic Affect Units”). No doubt this was in part due to the histories of the two systems’ architects. The primary designer of Minstrel, Scott Turner, was at that time a student of Dyer’s at UCLA, and Dyer had recently completed a dissertation at Yale influenced by Schank and Abelson’s ideas. (Dyer’s dissertation became the book In-Depth Understanding: A Computer Model of Integrated Processing for Narrative Comprehension, published by MIT Press in 1983.) The primary designer of Universe, Michael Lebowitz, had also recently written his dissertation at Yale under Schank’s supervision — contributing to Schank’s model of dynamic memory, especially in relation to story understanding. (Lebowitz’s dissertation was “Generalization and Memory in an Integrated Understanding System,” filed December 1980.)

Working with this shared background, it is not surprising that, on one level, the Minstrel and Universe models of authorial activity are quite similar. Both see the system as seeking to provide for the audience those elements identified as necessary for story understanding. Of especial importance, for both Minstrel and Universe, is the idea of the “point” or “theme” that the system is attempting to put forth — something notably absent in most of Tale-Spin‘s stories about characters trying to satisfy simple needs.

At the same time, the Minstrel and Universe systems are underpinned by rather different beliefs about how their processes relate to the behaviors of human authors. An examination of these differing beliefs is helpful in explaining the differing results achieved by the two efforts. And toward that is where my forthcoming posts will turn.