Comprehension

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Comprehension

• Kimberley Clow
• kclow2_at_uwo.ca
• http//instruct.uwo.ca/psychology/130/

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Outline

• Propositions
• Off-line vs. On-line Tasks
• Gaze Durations
• Structure Building Framework
• Discourse
• References Inferences
• Understanding
• Memory
• Conversation Rules

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Memory for Text

• Subjects read a passage of text
• He sent a letter about it to Galileo, the great
  Italian scientist.
• Recognition at various delays
• 0, 80, or 160 syllables
• Changed sentences
• Semantic
• Passive/active
• Formal

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Meaning as Propositions

• Propositions
• A set of conceptual nodes connected by labeled
  pathways that expresses the meaning of a sentence
• A mouse bit a cat
• or
• A cat was bitten by a mouse

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Deriving Propositions

• Children who are slow eat bread that is cold
• Slow children
• Children eat bread
• Bread is cold

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Evidence for Propositions

• Memory better for sentences with fewer
  propositions

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Priming Propositions
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Free Association

• Read Sentences
• Children who are slow eat bread that is cold
• Free Association
• What is the first word that comes to mind that is
  related to slow?
• Results
• Children
• Even though slow closer to eat than children

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Off-line vs. On-line Tasks

• Offline Tasks
• Measurement takes place after process complete
• Test memory after a passage is read
• Problem
• Measuring memory processes or reading processes?
• Online Task
• Measuring ongoing processes as they happen
• Gaze duration studies

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Gaze Duration Example
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Gaze Duration Studies
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Just Carpenter Model
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Structure Building Framework

• Model of Language Comprehension
• Process of building mental structures
• Propositions
• Concrete way of understanding propositions
• Three Principal Components
• Laying a foundation
• Mapping information onto the structure
• Shifting to new structures

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Laying a Foundation

• After the musician played the piano was quickly
  taken off the stage
• After the musician played
• Discourse focus
• The first character/idea of a sentence around
  which the structure is built.
• musician

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Mapping Information

• After the musician played the piano was quickly
  taken off the stage
• After the musician played the piano
• Discourse focus
• New words are mapped onto existing structure as
  they are read
• piano

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Shifting to a New Structure

• After the musician played the piano was quickly
  taken off the stage
• After the musician played the piano was quickly
• Discourse focus
• Old structure no longer fits, so start a new
  structure
• musician ? piano

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Discourse Psycholinguistics

• Traditional Psycholinguistics
• Determining what happens when we understand
  sentences
• Broader View
• How we resolve/understand sentences against the
  current discourse representation
• Sentence comprehension is a process that anchors
  the interpretation of the sentence to the
  representation of the prior text

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Processing of Connected Discourse

• What is discourse?
• Units of analysis larger than a sentence
• Applies to both spoken and written forms
• Ways we process (i.e., comprehend and remember)
  units of language larger than a sentence
• lectures
• personal narratives
• expository discourse

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Characteristics of Discourse

• Cohesion Interpretation of one sentence depends
  on other sentences
• Referential Cohesion
• Bill wanted to lend Susan some money. She really
  needed it.
• Temporal Cohesion
• Yesterday, Sara visited her grandmother. Later,
  she stopped at the gas station to get some gas.
• Coherence Logical consistency and semantic
  continuity
• Incoherence
• When the meanings of individual sentences do not
  hang together

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Referential Cohesion

• Referential Cohesion
• whether the nominal elements in discourse link
  together
• Reference
• objects and concepts that words or phrases stand
  for
• Example
• A woman came in. She is beautiful.
• The relation between a woman and she create
  referential cohesion of discourse

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Types of Referential Cohesion

• Anaphoric Reference
• Using an expression to refer back to something
  previously mentioned in discourse
• A woman came in. She is beautiful.
• Cataphoric Reference
• Using an expression to refer forward to something
  that is coming up in discourse
• This is where it is. I found the book in the
  fridge!

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Comprehending Anaphoric References

• Reading time of sentences affected by the degree
  of semantic relatedness between the antecedent
  expression and the anaphor
• (1) A tank passed by. The vehicle was full of
  people.
• (2) A bus passed by. The vehicle was full of
  people.
• Which one is easier to comprehend?
• Important factors
• Antecedent identifiability
• Given vs. new information

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Process of Understanding

• Process of understanding a sentence in discourse
  context involves 3 stages
• identifying the given and new info in the current
  sentence
• finding an antecedent in memory for the given
  information
• attaching the new information to this spot in
  memory

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Example

• (1) The boy saw a dog. It was such a cute dog
  with a red collar. He picked it up...
• (2) The boy saw a dog. He was sitting in front of
  his house, eating. He picked it up
• Comprehension
• He picked it up is easier to comprehend in (1)
  than (2)
• In (2), the antecedent is too far removed from
  the target

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Direct Matching vs. Bridging Inference

• Direct Matching
• When the given information in the target sentence
  directly matches an antecedent in the context
  sentence
• Easier for readers
• Bridging Inference
• When the given information in the target sentence
  does not directly match an antecedent in the
  context sentence
• The process of constructing a connection between
  concepts
• Causes processing and reading times to slow down

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Example

• Measure reading time of
• (1) Mary unpacked some beer. The beer was warm.
• (2) Mary unpacked some picnic supplies. The beer
  was warm.
• Readers spend considerably more time on (2) than
  (1)
• In (2), there is no explicit antecedent (no
  direct matching) for the reference the beer
  (requires bridging)
• the beer triggers a search for a matching
  antecedent
• should the search fail, the reader has to engage
  in an inference mechanism and relate it to prior
  discourse

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Reading Span

• Read a set of unrelated sentences aloud and
  recall last word in the set
• When at last his eyes opened, there was no gleam
  of triumph, no shade of anger. (recall anger)
• Reading Span Test
• The maximum number of sentences per set for which
  you can recall all the sentences last words
• Then do comprehension task
• Reading a passage and answer questions about the
  referents of pronouns
• Results
• Performance on pronoun reference was a function
  of reading span and distance between the pronoun
  and the antecedent
• Smaller reading spans smaller working memory
  capacity

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Memory for Discourse

• 3 Levels of Representation
• Surface form
• the exact words used
• Propositional representation
• interconnected network of ideas that underlie the
  surface forms
• Situation model
• a model of the state of affairs as described in
  the passage

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Level 1 Surface Form

• Read sentences
• (1) The confidence of Kofach was not unfounded.
  To stack the meeting for McDonald, the union had
  even brought in outsiders.
• (2) Kofach had been persuaded by the
  international to stack the meeting for McDonald.
  The union had even brought in outsiders.
• The final two clauses are physically identical
• surface form for second-last clause better in (1)
  than (2)
• Evidence that surface form is stored in working
  memory until its meaning is understood
• then surface form purged to make room for the
  next sentence

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Level 2 Propositions

• Participants presented with passages that
  required implicit inferences or were explicit
• Explicit text A carelessly discarded burning
  cigarette started a fire. The fire destroyed many
  acres of virgin forest.
• Implicit text A burning cigarette was carelessly
  discarded. The fire destroyed many acres of
  virgin forest.
• Sentence verification task
• A discarded cigarette started a fire yes or no?

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Results
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Level 3 Situational Model

• Read sentences such as
• (1) Three turtles rested on a floating log, and a
  fish swam beneath them
• (2) Three turtles beside on a floating log, and a
  fish swam beneath them
• Sentence verification task
• A fish swam beneath a floating log yes or no?
  
• Results
• People who read (1) were more likely to falsely
  identify the probe as part of what they had read

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The Structure of Conversations

• Taking Turns
• Little overlap between participants utterances
• Rules
• 1) The current speaker gets to select the next
  speaker
• 2) If Rule 1 is not used, anyone can become the
  next speaker
• Formal settings or conversations with strangers
  are more structured rule-goverened

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Conversational Maxims
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Violations

• Conversation occurs within a semantic environment
• People, purposes, rules of discourse, and the
  particular talk used in the conversation
• Stupid Talk
• Talk that doesnt know what environment it is in
• Crazy Talk
• Talk that creates and sustains an irrational
  environment