Outline

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Outline

• Introduction larger units of knowledge
• The challenge
• Acquiring a text message is like concept
  acquisition in childhood, but faster
• Three influences on comprehension
• The readers knowledge
• The structure of the text
• The 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 readers knowledge
• The structure of the text
• The interaction of these two

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3 influences on text comprehension

• The readers knowledge
• The structure of the text
• The interaction of these two

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The readers 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 cant remember what you dont
  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 youre seeing or recalling is
  schema-consistent, schema will help.
• If what youre seeing or recalling is
  schema-inconsistent, schema will hinder.
• Which is more likely?

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3 influences on text comprehension

• 1. The readers 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 storys global structure.
• A storys local detail.
• To illustrate the difference, lets look at
  Bernsteins West Side Story and the play its
  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
• RJ WSS
• Capulets Montagues Jets Sharks (gangs)
• 16th century Europe 20th century USA
• Horses, 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

• Well examine both levels in turn.
• First, well consider Thorndykes grammar of
  storytelling, a model of the global structure in
  a story.
• Then, well look at some local detail effects on
  comprehension and memory

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Thorndykes 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 read happily  
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Thorndykes 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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Thorndykes grammar of storytelling

• Setting ? characters location time
• Theme ? event a goal
• Plot ? episodes
• Resolution ? subgoal attempt outcome
• Experiments show that manipulating story
  structure influences both comprehension and
  memory performance.

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Effects of local detail - outline

• Internal structure at level of local detail
• Definition of proposition
• 2 processes for building structure
• Referring a comment back to a topic
• Building bridges between propositions
• Building bridges empirical evidence
• Haviland Clark (1974)
• 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
• Referring a comment back to a topic within a
  proposition.
• 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.
• 1. Horace got some beer out of the trunk. 2. The
  beer was warm.
• 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

• The readers knowledge
• The structure of the text
• The interaction of these two

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Integrating readers 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 Kintschs 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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Van Dijk Kintschs 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 Kintschs 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 readers goals can be
  deleted.