This page has been replaced with better material. See Reconsideration of Fundamental Strategies.
I’ll be deleting this page in a few days.
Two fundamentally different strategies for designing interactive storyworlds have arisen. I offer here a different prism through which to understand the strategies for interactive storytelling systems. I suggest that we use the metaphor of language. In this metaphor, we draw a distinction between sentences and words.
Interactive Fiction (IF)
In interactive fiction design, the fundamental element is the sentence. The smallest design component is a vertex in a network. The core structures and problems with IF designs are nicely summarized in an essay I wrote about 30 years ago: Flawed Methods for Interactive Storytelling. Very briefly, the problem with IF is the geometric explosion of possible states, which is usually countered with a number of schemes: foldback, ‘Kill ‘em if they stray’, obstructionism, or simple hard-wiring. The most progress has been made by transforming the standard tree structure of an IF storyworld into a directed graph, which allows the player to re-visit sites multiple times. This was in fact the structure of the very first such design, “Colossal Cave”, by Crowther and Woods. The crucial trick here is to establish a number of global variables whose values can be changed by visiting specific rooms; the changed values open up new sections of the storyworld. In the simplest example, the player must visit Room #27 in order to obtain the key, which is required to open the door in Room #9 leading to Room #38.
Most IF storyworlds rely on simple boolean variables; a few use small integer-values. I know of none that rely on the use of floating point values to any substantial degree, but I don’t follow the IF community closely enough to have any confidence in my experience here.
The vertices in an IF system traditionally represent spatial locations — rooms. However, they can represent any state. Sometime in the mid-1980s I proposed a series of educational storyworlds presenting the player with socratic dialogues. The steps in the argument — both correct and erroneous — took the place of rooms. The Socratic software presented the player with arguments followed by possible responses by the player. I wrote a short demonstration of this idea, but did not carry it far.
It would be more difficult to have the rooms represent events. For example, one chunk of the storyworld could represent the player as a teenager going on a date. The player must then navigate the many possible actions and their repercussions. This would require global variables representing the mood of the computer character. Or a geopolitical conflict could be modeled with a set of rooms representing policy decisions of the player.
Another dimension in which IF could be expanded concerns the connections between vertices (edges). These are usually bidirectional absolute connections; a player can readily move from one vertices to a connected node and back again by the same connection. The edges could be made unidirectional: the player can move in only one direction along an edge. Or they could have varying lengths. That is, the player can expend multiple “turns” traversing an edge. This permits the player to consider time consumption in traversing edges. However, for this to be practical, the storyworld must maintain a map for the player recording what the player has learned so far. This is entirely too spatial for my taste. Another possibility would be for the traversal to consume some resource that the player must marshal. Some edges will be cheap to traverse, and others will be more expensive.
An even wilder possibility is to make edges variable by having them shift between vertices. In other words, the edge between Room #26 and Room #18 might shift one terminal to, say, Room #22, connecting Room #26 and Room #22. This could take place randomly, or according to a schedule that the player could learn about, or under the player’s control. I am uncertain as to whether this would have any value for play, and it would certainly be difficult to justify in terms of dramatic significance. By way of example, here’s one possibility: kissing the girl (Room #8 to Room #11) advances the romance; but after learning that the girl is the player’s sister, kissing her traverses Room #8 to Room #37.
Those wishing to extend the possibilities of IF would do well to study network theory. While many of its concepts are of little utility to IF, some raise interesting possibilities. In particular, some of the ideas of social network analysis have fascinating possibilities if applied to IF. The diffusion of information through a social network (commonly called “gossip”) is an interesting case. The concepts of betweenness and centrality can be usefully applied to storyworld networks.
Storytron Strategies
The strategy that I have pursued for thirty years uses a single word or phrase as its smallest component. The user assembles a sentence out of words or phrases and then executes the resulting sentence. Let’s compare and contrast these two strategies.
First, let’s consider the means by which meaning is attached to the player’s actions. The IF strategy hard-wires meaning directly to the player’s choice. That is, a player in Room #27 who choose Door B elicits a pre-specified meaning or dramatic response.
The Storytron strategy assigns meaning abstractly. Each verb has meanings attached to it, but those meanings are variables whose values are determined by the other components of the sentence.
A simple way to understand this is to think in terms of numbers and variables.
This reveals one reason why I failed so badly with Erasmatron-Storytron: abstracting dramatic interaction is immensely difficult. For the entire history of storytelling — tens of thousands of years — we have thought of dramatic interaction in terms of specific instantiations. Nobody has ever written any formulae for dramatic behavior. Interactive fiction keeps us in familiar territory, but the Storytron strategy takes us into radically different territory.
Some will object that reducing dramatic behavior to mathematical form is not only dehumanizing, but flatly impossible. These are the same people who insisted that speeds above 30 mph would prove deadly to humans, that machine flight was impossible, and that rockets could never move through space because there is nothing to push against. They can point to my own failures to support their pessimistic assessment, but I am only the first to tread this path; others will push further down the path. Storytelling is within our cognitive grasp; now the task is to translate those cognitive processes into mathematical ones — a considerably easier task.