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Comprehension

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Comprehension Powered By Docstoc
					Comprehension
Kimberley Clow
kclow2@uwo.ca

http://instruct.uwo.ca/psychology/130/
Outline
  Propositions
  Off-line vs. On-line Tasks
     Gaze Durations
  Structure Building Framework
  Discourse
     References & Inferences
     Understanding
     Memory
     Conversation Rules
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
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
Deriving Propositions
  Children who are slow eat bread that is cold
     Slow children
     Children eat bread
     Bread is cold
Evidence for Propositions
  Memory better for sentences with fewer
  propositions
Priming Propositions
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”
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
Gaze Duration Example
Gaze Duration Studies
Just & Carpenter Model
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
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
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
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
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
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
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
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
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!
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
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
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
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
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
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
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
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
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?
Results
                         Reaction times to verify test sentences
                  4.8
                  4.7
                  4.6
                  4.5
 Latency (sec)




                  4.4
                                                                   Implicit
                  4.3
                                                                   Explicit
                  4.2
                  4.1
                    4
                  3.9
                  3.8
                 Immediate   Delay (15
                               min)
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
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
Conversational Maxims
Violations
  Conversation occurs within a semantic
  environment
        People, purposes, rules of discourse, and the
        particular talk used in the conversation
  Stupid Talk
     Talk that doesn’t know what environment it
      is in
  Crazy Talk
     Talk that creates and sustains an irrational
      environment

				
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