core elements of an interactive story

Embracing the Combinatorial Explosion: A Brief Prescription for Interactive Story R&D
​by Andrew Stern

Interactive stories are a technologically daunting challenge.  They require several support technologies that are still underdeveloped - e.g. a lot less money has gone into interactive story technologies than AI voice tech, and even that is still developing.  

As a result "interactive story as a narrative form can be said to be in an infant stage of development akin to the first cinematic films of the early 20th century" (p. 2)

"Putting aside superficial features such as high fidelity graphics and animation, the most successful games offer players true agency - the ability for players to have persisitent, meaningful effects on the events of the experience.  Today's games have only achieved agency in the domain of action - or puzzle oriented game-play" (p.2)

EMBRACING THE COMBINATORIAL EXPLOSION:
The quintessential requirements of an interactive story - and a research agenda.
1. Agency is primary - implicit in this is the promise to directly affect the plot of the story.
2. Generation - in order to achieve this requires vast amounts of content, so to overcome branching fatigue and costs we need systems that can content generate on the fly.  Pioneer projects include Talespin, Universe and Minstrel.
3. Interface - Once players are directing the plots of stories about people, expressive natural language and gesture interfaces will be required.
4. Connection - If generation is akin to speaking, and interface is akin to listening, then the two phases need to be connected with the ability to manage the drama and reason about the player's input.
5. Terminology problem - If players have true agency the interaction is not being told, but generated.  "Interactive storymaking" is more accurate, if awkward.  For now, the researchers drop the verb and refer instead to "interactive stories", noting the need for a new term.

Future recommendations including building new systems to enable new types of interactive stories and making them available for public feedback

Stern, A., 2008, November. Embracing the combinatorial explosion: A brief prescription for interactive story R&D. In Joint International Conference on Interactive Digital Storytelling (pp. 1-5). Springer, Berlin, Heidelberg.