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Outline

1. Introduction – larger units of knowledge2. The challenge

Acquiring a text message is like concept acquisition in childhood, but faster

3. Three influences on comprehensionThe reader’s knowledgeThe structure of the textThe interaction of these two

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Introduction

In Chapter 9, we looked at how concepts are mentally represented and accessed.

Concepts might be stored as abstract representations (e.g., prototypes) or as a set of experiences with exemplars.

Chapter 11 is about how we deal with knowledge at a larger scale – for example, the scale of texts.

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Introduction

To make the distinction clear:

Whale is a concept

Moby Dick is a text, in fact, a story about a whale and the man who hunted it.

A text is a very large unit of knowledge. How can we store it in memory?

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The Challenge

Think about acquiring concepts in childhood.

involves repetition and successive refinement

e.g, doggie – first, all four-legged animals, then, small four-legged animals, then dogs.

as children, we have years to accomplish this

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The challenge

Reading a text, we go through a similar process with larger units in a much shorter time – perhaps minutes.

Reading a text, we have to acquire and hold in memory a representation of what the text is about.

‘Reading a text’ may mean reading words written on a page or reading a situation.

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3 influences on text comprehension

The task is to read and remember a text-level message. What influences our ability to encode, store, and retrieve larger units of meaning?

The reader’s knowledge

The structure of the text

The interaction of these two

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3 influences on text comprehension

1. The reader’s knowledge

2. The structure of the text

3. The interaction of these two

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The reader’s knowledge

What kind of knowledge influences comprehension?

Schema knowledge

Which processes do schemas influence?

Schemas have effects at both encoding, and retrieval.

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Schema effects at encoding

Bransford & Johnson (1973)

Balloon serenade passage. Context provided schema.

D.V. = # of propositions remembered No context, 3.6. Context after reading,

3.6. Context before reading, 8.0. Point: you can’t remember what you

don’t comprehend.

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Schema effects at retrieval

Dooling & Christianson (1973)

Read this passage:

Carol Harris was a problem child from birth. She was wild, stubborn, and violent. By the time Carol turned eight, she was still unmanageable. Her parents were very concerned about her mental health. There was no good institution in her state. Her parents finally decided to take some action. They hired a private teacher for Carol.

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Dooling & Christianson (1973)

2 groups asked to read that passage 1 week later, subjects asked whether

following sentence was in passage:

“She was deaf, dumb, and blind.”

One group got no further information. One group told, just before recall,

story was really about Helen Keller.

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Dooling & Christianson (1973) Results

Very few people in the control group said ‘Yes,’ (e.g., test sentence was in passage)

Many people told that the story was about Helen Keller said ‘Yes’ to test sentence

Retrieval process influenced by world knowledge, including knowledge of who Helen Keller was.

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Schema effects - conclusions

Bransford & Johnson: without schema, passage was difficult

to understand and encode. Schema made memory performance more accurate.

Dooling & Christianson: without schema, passage easy to

comprehend. Schema produced a retrieval error.

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Schema effects - conclusions

Schemas can have positive or negative effects at both encoding and retrieval.

If what you’re seeing or recalling is schema-consistent, schema will help.

If what you’re seeing or recalling is schema-inconsistent, schema will hinder.

Which is more likely?

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3 influences on text comprehension

1. The reader’s knowledge

2. The structure of the text

3. The interaction of these two

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The structure of the text

Comprehension and memory for text are affected by:

A story’s global structure. A story’s local detail.

To illustrate the difference, let’s look at Bernstein’s West Side Story and the play it’s based on, Romeo & Juliet

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Romeo & Juliet vs. West Side Story

Global structure (very briefly):

feuding social groups young lovers from opposing sides their love overwhelms reason dire results

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Romeo & Juliet vs. West Side Story

Local detail:

R&J WSS

Capulets & Montagues Jets & Sharks (gangs)16th century Europe 20th century USAHorses, swords Cars, guns

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Global structure vs. local detail

Both influence comprehension.

Changing global structure may impair comprehension – consider movie Memento: No theme or plot to work with.

Aspects of local detail may also affect ease of understanding and memory for a text

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Global structure vs. local detail

We’ll examine both levels in turn.

First, we’ll consider Thorndyke’s ‘grammar of storytelling,’ a model of the global structure in a story.

Then, we’ll look at some local detail effects on comprehension and memory

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Thorndyke’s grammar of storytelling

Thorndyke (1975)

Developed a grammar of story-telling. Basic idea is very similar to grammar

of a sentence: sentences have hierarchical structure as in example on next slide

Thorndyke: stories have analagous structure.

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Sentence  

Noun Phrase Verb Phrase  

Determiner Adjective Noun Verb Adverb

 The good student readhappily 

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Thorndyke’s grammar of storytelling

Just as a sentence contains phrases that in turn contain words. Stories consist of

a Setting a Theme a Plot, and a Resolution. Each of these contains sub-

components.

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Thorndyke’s grammar of storytelling

Setting characters + location + timeTheme event + a goalPlot episodesResolution subgoal + attempt + outcome

Experiments show that manipulating story structure influences both comprehension and memory performance.

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Effects of local detail - outline

1. Internal structure at level of local detail2. Definition of proposition3. 2 processes for building structure:

i. Referring a comment back to a topicii. Building bridges between propositions

4. Building bridges – empirical evidencei. Haviland & Clark (1974)ii. Kintsch (1974)

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Effects of local detail

Texts have structure at a lower level, the level of local detail.

Local structure is made of propositions During reading, that structure is built

through two processes:1. Referring a comment back to a topic within a proposition.2. Building bridges between propositions.

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Propositions

In reading, you interpret and store a passage as a structured set of propositions.

A proposition is the smallest unit of meaning that can be true or false.

Dog – no sense in which this can be true or false.

The dog is blue – this can be true or false.

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Building structure out of propositions

Process #1: Referring a comment back to a topic

The dog I saw that lady with the flowered hat walking yesterday was a spaniel.

The more propositions appear between topic and comment, the tougher comprehension is.

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.

Building structure out of propositions

Process #2: Bridging between two ideas.

“John threw a cigarette out of his window while driving through the forest. The fire destroyed hundreds of acres.”

Here, reader adds an implicit proposition: The cigarette caused the fire.

Comprehension is easier if bridging propositions are explicit

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Building structure out of propositions: evidence

Haviland & Clark (1974) –Task: press button when you comprehend second sentence.

A. 1. Horace got some beer out of the trunk. 2. The beer was warm.

B. 1. Horace was especially fond of beer. 2. The beer was warm.

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Haviland & Clark (1974) - Results

People responded faster in condition A than in condition B.

Conclusion:

In B, extra time was necessary to make the bridge – to work out that beer in the second sentence was related to beer in the first sentence. This was easier in A.

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Building structure out of propositions - evidence

Kintsch (1974) Gave subjects sentences like the one about John and the fire above.

Tested their memory either immediately after reading or 20 minutes later.

Immediate test: Memory better for explicit propositions.

Later test: Memory equal for two kinds.

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Kintsch (1974) - Conclusion

Text structure is developed as passage read.

When new information is integrated into that text structure, surface form of text (the actual words) can be discarded.

Passage stored in memory as Propositional structure. Implicit and explicit propositions are equal in that structure.

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3 influences on text comprehension

1. The reader’s knowledge

2. The structure of the text

3. The interaction of these two

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Integrating reader’s knowledge & text

Dominant figure here is Walter Kintsch.

Van Dijk & Kintsch (1978) argued for three different levels of representation of texts:

Surface code Textbase Situation model

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Van Dijk & Kintsch’s model

Surface code represents a text using the actual words in the text.

Textbase represents a text as propositions (explicit and implicit).

Situation model – a mental model; integrates text information with pre-existing world-knowledge (also in proposition form, but more elaborate than textbase).

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SurfaceCode

The text

SituationModel

Knowledge about the world + textTextbase

Knowledge about the text

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Van Dijk & Kintsch’s model

Basic elements of model:

Comprehension is an active process. Explicit propositions are extracted

from surface code Implicit propositions are inferred All propositions are organized around

structure reader expects (setting, conflict, etc.)

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Van Dijk & Kintsch’s model

Comprehension also involves higher level processes. As propositions are extracted from the text:

world knowledge lets you fill in missing parts from semantic memory

parts not relevant to reader’s goals can be deleted.