From Narratology to Formal Narrative Structures

What is Relevant in a Story?

Carlos León

<[email protected]>

University of Hamburg

Semantics and Syntax: A Legacy of Alan Turing

Isaac Newton Institute

Cambridge

12/1/2012

We use narratives every day

History

Education

Narrative content is not only literature

A mathematical proof

What you did yesterday

Episodic memory

What you should do when you go to a restaurant

C. León (U. Hamburg) Formal Narrative Structures 12/1/2012 2 / 14

History

Education

Episodic memory

History

Education

Episodic memory

History

Education

Episodic memory

History

Education

Episodic memory

History

Education

Episodic memory

History

Education

Episodic memory

History

Education

Episodic memory

History

Education

Episodic memory

History

Education

Episodic memory

History

Education

Episodic memory

Computational Narrative is important in AI

Narratives can store a huge amount of common sense knowledge

This is relevant for computation in general and AI in particular

From a computational point of view, knowledge is not only representation

Knowledge management is also a crucial part (time, events, relations, causality)

General common sense knowledge can not be represented and processed without

taking narrative properties into account

We are interested in the properties that define narrative similarity

If a mathematical proof is a narrative, we could find out whether two proofs are basically the same

Narratology influences Computational Narrative

Classic Narratology studies the structural properties of stories

Beginning, middle, end

Exposition, climax, denouement

This suggest some sense of syntax in stories

Can we properly define a narration in terms of its structure?

Can we properly represent a story computationally in terms of its structure?

Narratology assumes cognitive properties way beyond AI

How do we know if a narrative conflict has been solved?

How does a computer know if a narrative conflict has been solved?

A computational definition of syntax

When the rules for using all the symbols are known by the computer, no external human

understanding is needed

Computers are great at applying rules to symbols

Therefore, we’d like to have a syntactical definition of narratives

A useful structural definition of stories is maybe less natural than focusing on the chain of

events, but can be more powerful as a computational solution

A computational definition of semantics

A story (as a computer sees it)

Can we assign any meaning to these symbols?

happy(john), give(john, mary, ball)

die(john), give(john, mary, ball)

die(cat), eat(cat, fish)

What the symbols mean to us (semantics) is crucial

What amount of semantics do we need?

To what extent can we rely on structural properties?

The more developed the computational system, the more complicated the symbols

that can be processed. Do these complex symbols become syntax?

Many Different Formal Systems

Knowledge must be represented in terms of manageable symbols

A, B, C, D, E, · · ·

hate(john, mary), attack(john, mary), die(mary), happy(john)

Which one is better?

A, B, C, D, E, · · ·

We do not know which formalization is the correct one

When identifying narrative similarity, the level of abstraction is important

Sequence of events

We are trying to find out what the correct formal system is

A family of formal systems with different levels of granularity is probably the best solution

Sequence of events

What to include in the formalization?

The formalization process implies abstraction

This abstraction usually implies some sense of summarization

Mary was a woman. Mary hated John. Mary attacked John. John died. Mary was

happy.

John was a man. John hated Mary. John attacked Mary. Mary died. John was happy.

Not all the information is relevant at a certain level

It is important to finding out what levels of similarity we use

happy.

How do people formalize?

Stories and everyday narrative is not formally represented

Therefore, a formal system is not enough, a formalizing process is needed

In order to be able to compare the structural properties, we need a robust formalizing

methodology

Computers can not do this yet, humans must perform formalization

A natural formalization does not exist

methodology

Is everyone well trained?

Formalizing narratives is not intuitive

People must be trained

Therefore only experts can formalize a story

We need control over the formalization process

Without a natural formalization, the comparison of stories is tainted unless the

formalization is controlled very carefully

Experiments for finding out how humans create formalizations

Narrative annotation with proppian functions

Results show that do not agree with Propp

Basic summarization

We want to know which parts are highlighted by test subjects.

Simple sentences to lesen linguistic side-effects

We plan to compare the results against proppian experiment

Basic summarization

Conclusions

Narratives represent an important part of human knowledge

Narratology offers structural analysis of narratives

From a formal point of view, the threshold between semantics and syntax is not clear

A robust formal system for story similarity must have different levels of granularity

Some levels will be more syntactical

Some levels will be more semantical

The formalization task is complex and must be controlled carefully

Experiments on human behavior (tagging, summarization, formalization) can help to

understand what the relevant parts of a story are

From Narratology to Formal Narrative Structures

What is Relevant in a Story?

Carlos León

<[email protected]>

University of Hamburg

Semantics and Syntax: A Legacy of Alan Turing

Isaac Newton Institute

Cambridge

12/1/2012

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