Issues in Sentence Comprehension

1
Issues in Sentence Comprehension

• Parallel vs Serial
• Parallel Construct multiple interpretations
  wait for evidence about which is right
• Serial Construct only 1 interpretation at
  first, then try another only if that turns out
  to be wrong (two stages)
• Which makes more sense depends on whether easier
  to
• Construct multiple interpretations hold onto
  them long enough to avoid making a mistake
• Or construct just one interpretation hope its
  right
• If first choice usually right, serial approach
  could be more efficient

2

• Modular vs Interactive
• Modular Take only syntactic properties of words
  (N, V, Prep, etc.) phrase structure options
  into account at first
• Interactive Take word meaning, context,
  general knowledge into account all along
• Again, which makes more sense depends on whether
  its easier to
• Make quick first guesses based on just syntactic
  categories of words some basic phrase structure
  patterns
• Or combine syntax, meaning, context, knowledge
  fast enough in first place

3
Garden Path Model (Frazier, Rayner, Clifton, F.
Ferreira)

• Influential serial (two-stage) modular parsing
  model
• Name comes from claim that we frequently
  garden-path during comprehension
• But only become aware of it occasionally
• Minimal Attachment Strategy
• Whenever multiple structural options, start with
  simplest one
• i.e. one requiring adding fewest nodes to phrase
  structure tree at that point in sentence

4
Structural Ambiguity

• S
  S
• VP
  VP
  
• 
  NP
• NP V NP PP NP
  V NP PP
• A thief shot the cop in the park. A thief
  shot the cop in the park.

Attachment ambiguity
5
Prediction of GP Model

• All sentences with Nonminimal Attachment (NMA)
  structures should be harder than all sentences
  with Minimal Attachment (MA) structures
• Because always have to revise a wrong first guess
  in NMA sentences
• That should take some time
• Though often not enough to become aware of problem

6
Rayner, Carlson, Frazier (1983)

• Measured how long people spent reading different
  regions of sentences using an eyetracker
• Stimuli
• Minimally Attached
• The doctor examined the patient with the
  stethoscope,
• but he couldnt figure out what was wrong.
• Non-minimally Attached
• The doctor examined the patient with the
  headache,
• but he couldnt figure out what was wrong.
• Prediction of GP Model
• People should read headache the words after it
  more slowly than stethoscope the words after it

7
Eyetracking (Dual Purkinje Tracker)

• - Dim infrared light shines on eye
• - Several reflections bounce back from different
  layers in eye
• Relative positions of different reflections show
  very accurately
• where eye is pointing

8
Results First Pass Times
9
Interpretation

• Results seem to support GP Model
• Slower reading times after headache suggest
  people garden-pathed had to reinterpret
• But, do Rayner et al.s stimuli provide fair test
  of MA Strategy?
• Temporary ambiguity starts at with
• Is there anything earlier in sentence that might
  bias interpretation one way or other?
• The verb examined, maybe?
• Does it lead to expectations for certain kinds of
  phrases following it? (Bresnan)

10
Verb Argument Structure

• Verbs are the most important words in sentences
• All other words are interpreted relative to the
  verb
• The librarian put the book on the shelf.
• put requires all 3 of these arguments to be in
  the sentence,
• i.e. all 3 arguments are obligatory
• Subject / Agent librarian
• Object / Patient (Theme) book
• Location shelf
• The librarian put.
• The librarian put the book.
• The librarian put on the shelf.
• Most verbs have some optional arguments
• The doctor examined the patient.
• The doctor examined the patient with a
  stethoscope.
• The doctor examined.

11
Verb Bias

• Verbs differ in how often they are used with
  their optional arguments
• examine is probably often used with an optional
  Instrument
• Maybe Rayner et al. happened to use lots of verbs
  that often take the kinds of arguments that were
  present in MA versions?
• Would bias results in favor of MA sentences

12
Taraban McClelland (1988)

• Measured reading times using self-paced moving
  window technique
• Stimuli
• Used Rayner et al.s materials
• Plus just as many more like
• MA John read the article in the bathtub
• while he was waiting for a call.
• NMA John read the article in the magazine
• while he was waiting for a call.
• Where John read the article in the ... seems to
  lead to expectation of
• something modifying article ( NMA) rather than a
  location where the reading event took place ( MA)

13
Results
14
Taraban McClellands Conclusions

• No general Minimal Attachment Strategy
• People use knowledge about particular words how
  theyre most likely to be used to guide their
  interpretation
• Especially verbs?
• Serial vs Parallel
• Supports serial model should be no GP if fully
  parallel
• Modular/Interactive
• If verb bias is syntactic, results have no
  consequence
• If word meaning or extra-sentential context had
  an immediate effect, that would clearly support
  Interactive