Paper Overview: Story vs Interaction
Hi everyone, this is Jean-Noël from Immersive Consulting.
Today I would like to talk about a research paper in Interactive Storytelling.
As I was explaining in another article, in order to immerse people in another universe, it’s very important for them to interact. When your actions have an impact on the world, you feel immediately more present in it.
However, it quickly appears that with immersive storytelling, there is a clear opposition between defining a story beforehand, and the freedom players have through interaction.
Indeed, how to be sure that the story unfolds as planned if the player is free? Shouldn’t we question the very notion of a predefined story?
Mediating the tension between plot and interaction (Magerko, Laird, 2004)
That’s the interrogations at the heart of the article I’m presenting to you in today. The article has been published in 2004 by Brian Magerko and John E. Laird, and is named “Mediating the tension between plot and interaction”.
The paper introduces IDA, for Interactive Drama Architecture, and focus on a specific approach to this conflict between interaction and story: allowing the story to take a different shape according to the players actions.
In order to do that, they thought over the way to write a story. The author does not specify the entire detailed events, but rather set a global structure, which won’t be modified, and a pacing to respect. This is the content inside this structure which may vary and take form through the player’s actions.
The story’s structure
This structure is made of a partially ordered list of events. These events have pre-conditions which must be met in order to be triggered. In this pre-conditions, there may be a notion of timing, meaning in which interval the author wants the event to be triggered, in order to reach the desired pacing.
These events can have variables elements, that the author does not completely specify, and which will be decided by the player’s actions when the story is actually executed.
For instance, the author can specify that between the first and second minute, a dialog between two characters must start. He does not have to specify the place, which will be decided by IDA (the Interactive Drama Architecture) relative to the player’s position, and if she should be hearing this dialogue from a distance, or be plainly visible by the two characters.
Therefore, it’s in a way the player who finalizes the story set up by the author.
How IDA works?
How does IDA work? First, IDA uses a player model. This player model depicts what the player knows about the world and the current story, and is constantly updated. The characters in the world use a cognitive model named “Soar” which allows IDA to direct them while maintaining a coherency from the player’s point of view.
IDA will then control step by step the triggering of the events, according to the evolution of the world’s state.
While IDA unfolds the story, it also uses the player model in order to predict her actions. The prediction will tell that the story is threatened if the pre-conditions for the next events are no longer valid, or if a key event may not occur in time. Sometimes, IDA may also just notice that a player’s action is problematic and must be repaired.
For instance, IDA could detect that the player may spend 5 minutes inside a room in order to inspect its objects, when a key event is supposed to happen in another room 2 minutes later. Or simply, a key object may have been destroyed, for instance a book containing a mandatory piece of information for the player in order for her to progress in the story.
To prevent such things to happen, IDA can control the environment, the objects, or the characters. When the player may spend too much time in the same place, visual or sound cues can be used, by playing with the environment lighting to catch her attention, or triggering a heavy sound localized where the player should go. In the destroyed book case, IDA can place again the piece of information in another book, or in a future dialogue.
What about the coherency?
Then comes the question of the coherency. How to be sure that these modifications remain credible in the player’s eyes? The player model is there again to help us. Indeed, IDA knows what the player knows, and therefore what she doesn’t know, and so can alter the story and the world without her to notice. For instance, by creating a new book in a room the player did not visit yet.
This is it for this quick introduction to the Interactive Drama Architecture presented by Brian Magerko and John E. Laird in their paper. I think it’s a good introduction to the notion of conflict between author intent and player’s interaction. It allows to spotlight the idea to think over the way we make stories.
I hope to have the opportunity to develop this aspect of immersive storytelling in other articles.
Thanks for reading this article. If you liked it, do not hesitate to share or to get in touch!