An Introduction to
Computational
Narrative
Jarmo Laaksolahti
SICS
Interactive story systems

Litterature
 Hypertext novels
 “Construct your own

IRL
 Improv theater
 (Live) Role-playing

adventure” books
games
Computational
 Computer
 MUDs
games
 Childrens’
story creation applications
Outline



Interactive narrative
What is narrative anyway?
Structuring interactive narrative
 Drama

management
Examples of systems
 Story
generators
 Emergent narrative
 ID Systems
Traditional stories

The author controls
 What
happens when in the story world
 What the reader finds out about it, and when

The reader controls

Whether to read on or stop (or skip)
Interactive stories

Author shares control
 Players
actively participate in the creation of their own
experience

Conflicting demands
 Players
want freedom to do and see whatever they
find interesting (?)
 Authors want to tell their story

How can interactivity and story be combined!?
Critical Voices

Ludology
 Narratives
retell past events and thus cannot
be interactive (narration collapses)
 Story and roles constrain interactivity

Narratology
 Interactivity
only allows simple/uninteresting
stories to be formed
Stories and Games

What are the differences?
 Games
focus on interactivity, stories on
control
 Games involve solving puzzles, scoring points
and winning

What is the role of story in games?
 Games
often involve stories (in some way)
don’t they?
What is a narrative?


A narrative is an account of
events that has happened
to someone.
Narratives order events
temporally…


…and causally


C happened because of A.
Narratives are about
important events.


A happened first, then B and
C.
Importance depends on the
situation
Focus on characters.
because of
A
then
B
then
C
Story and Plot (1)

Story refers to a sequence of events as it has
actually happened in a story world.
 A jealous
man suspecting that his wife is cheating on
him decides to leave her.

Plot refers to the sequence of events as it is
actually related.
 The
story can be told in reverse: the man leaves and
only later do we get to know why.

Plot (re)arranges story events in various ways.
Story and Plot (2)


Readers access the
story through the plot
Is plot media
independent?
 Mental

Reader
Mediate
Interpret
B
A
C
Plot
events
Plot and media are
tightly intertwined (I
think)
Arrange
Access
because of
A
then
B
Story
then
C
Story structure

Story Values
 Love/hate,

life/death, rich/poor, …
Events that turn values in increasing order
 Beats
 Scenes
 Sequences
 Acts
Story = Character + Plot



Characters should have “…qualities that allows
an audience to believe that the character could
and would do what he does” (McKee, 1997)
No need to model the real thing!!
Instead model folk-theoretical understanding of
 Emotions
 Social-relations
…
The wedge
Potential
Possible
Probable
Necessary
Story arc
Complication
5
4
6
3
1
2
7
Time
1.
2.
3.
4.
5.
6.
7.
Exposition
Inciting incident
Rising action
Crisis
Climax
Falling action
Denouement
Levels of Interaction

Aren’t all stories interactive?


Constructivism
because of
Interactive Plot

Make the links between
events virtual
 Creating new plots
A
then
B
then
C
because of

Interactive Story

Make the events themselves
virtual
 Creating new story events
A
then
B
then
C
Structure of Interactive
Narrative
“The narrative potential of the interactive
text is a function of its system of links”
(Ryan, 2001)
 Does this also apply to other media?

The complete graph




Fully connected graph
Player can navigate
as she likes
Difficult to create
events that can be
experienced in any
order
Hard to guarantee
narrative coherence
The Network




Cyclic graph
The player is partially
limited
Coherence can only
be locally guaranteed
Common in hypertext
novels
The Tree





Does not allow cycles
Only one path from the
root node to each leaf
node
Easy to guarantee
narrative coherence
Suffers from
combinatorial explosion
Used in role-playing
books
The vector with branches





Main story is noninteractive
The player can visit the
side branches
Players can decide the
level of detail
Popular in children's
(educational) games
…and perhaps RPG’s?
The Maze






Traversed from start to goal
along several paths
May contain cycles
May allow backtracking from
dead ends
Narrative coherence is
achieved (?) because all paths
attempt to reach the same goal
Number of plots = number of
complete traversals
Not all are equally satisfying
R.I.P
Start
Goal





No cycles!
Combines narrative with
interactivity (to some
degree)
Trivializes the effects of
player actions
Significance can be
restored by making the
system context-sensitive
Computer games are
often of this kind
Choice
The Directed Graph
Time
The Hidden Story
Reading path


The player discovers
the pre-history
Contains two
narrative levels
 The
fixed hidden story
 The atemporal
network of the readers
investigation

E.g. used in Myst
Story to be discovered
Hypertext Novels
The Braided Plot



The story is
determinate
Players experience
events from different
perspectives
Players can backtrack
(relive) events from
another perspective
Space
Time
Drama management
An alternative to explicitly coded links
 Policy for “story piece” selection

Actual sequence
Selection policy
Story library
Important Questions
What are the story moves?
 How is the desired story represented?
 What is the selection policy?
 When does selection happen?

Narrative Systems

Properties of the systems we will look at
 Player experience not authoring
 Computers constitute the medium
 A program is involved in creating/guiding the
 Players can influence the systems behavior

narrative
Types of systems
 Story generators
 Character based
 ID
…
systems
systems - emergent narrative
Tale-Spin – James Meehan


Early (1976) story generation system
Players specify a set of






character goals
facts
relationships
The system creates an animal fable using the provided
parameters
PhD thesis: “The Metanovel: Writing stories by
computer”, Yale,1976
LISP implementation available (micro tale-spin)
Puppet
Playwright – Brenda Laurel





Early design of an ID system (not implemented)
Expert system acting as a playwright
Collects suggestions from each character about
what to do
Simulates the effect of these actions and
chooses the first acceptable action
Reading material: Computers as Theatre,
Addison Wesley, 1993
Façade – Mateas & Stern





Story a la “Who’s afraid
of Virginia wolf”
Interaction through
natural language dialog
within story context
The player plays a
character in the story
First person view
To be released (free)
2003
Façade architecture
Drama Manager
(sequences beats)
Bag of beats (~100)
History
Recognizers
Previous action
beat
beat beat
beat beatbeat
Scene
Current
story
values
Selected beat
beat
beat
beat
time
beat
Activity not part of a beat
Desired value
arc(s)
surface text
Trip
Player
Grace
Story World
discourse acts
discourse acts
reactions
Natural Language
Understanding
Other systems
Erasmatron – http://www.erasmatazz.com/
 Mimesis – http://mimesis.csc.ncsu.edu/
 IDTension – http://www.idtension.com/
…

More info about my own work

Jarmo Laaksolahti (jarmo@sics.se)