Sentence Comprehension

1
Sentence Comprehension
2
Where are we?

• Levels of processing in language processing
• Speech/letter perception
• Word recognition
• Lexical access vs. lexical selection
• Sentence comprehension
• Syntactic (is this a module?)
• Semantic analysis
• Discourse/Message level
• Pragmatics

3
Word Recognition and Sentence Comprehension

• Word recognition is an essential input to
  sentence comprehension.
• What does this mean?
• In both reading and listening, we begin to
  develop syntactic semantic representations of
  the sentence as soon as we hear the first words
  (recall Marslen-Wilson, 1973).
• The professor explained
• The horse raced

4
Garden Path Sentences

• The horse raced past the barn.
• NP VP
  
• The horse raced past the barn fell.
• NP relative clause VP
  
• We build sentence-level structures and
  interpretations incrementally.
• There is a lot of temporary ambiguity.
• Sometimes we choose the wrong alternative.

5
Incremental Parsing Interpretation

• Garden path sentences (Bever, 1970)
• The horse raced past the barn fell.
• (Main Clause/Relative Clause ambiguity)
• GP depends upon whether first NP is a good
  agent/experiencer, and on frequency of past
  participle form of verb (Trueswell, 1996).
• The thief (who was) searched by the police had
  weapons. good agent, infreq participle
• The award (that was) accepted by the man was
  impressive. poor agent, freq participle
• Support for Constraint-based Lexicalist Account
  of syntactic processing (parsing)

6
Two critical components of Sentence Comprehension

• Syntactic Analysis
• Semantic Interpretation
•  Within a language, syntactic structure largely
  determines meaning (or vice versa)
• Put the ball in the box on the table.
• Can semantic interpretation guide syntactic
  analysis in a top-down manner?
• Constraint-based lexicalist YES
• Fraziers Garden Path model -- NO

7
Sentence Comprehension difficulty is not always
related to ambiguity/garden path!

• The paper that the pencil that the chalk touched
  marked burned.
•   
• Even without ambiguity, it is difficult to
  identify the hierarchical structure. Once you
  figure out the structure, the meaning becomes
  clear...
•  
• The paper burned.
• that the pencil marked __
• that the chalk touched __

8
Do semantic cues help?

• The water that the boy that the bee stung carried
  spilled.
• The water spilled.
• that the boy carried __
• that the bee stung __

9
 Frequently, processing difficulty is caused by a
structural ambiguity.

• The cotton shirts are made from grows in
  Georgia.
• (The cotton shirts) (are made from...)
• (The cotton (shirts are made from)) (grows in...)
•  
• Two syntactic structures are possible. If you
  select the wrong one, you garden path.
• But ambiguity doesnt necessarily cause
  processing difficulty were usually unaware of
  structural ambiguities.

10

• Theories of sentence comprehension should be able
  to predict processing difficulty in both
  ambiguous and unambiguous sentences.
• Structurally ambiguous sentences have been
  especially important in testing theories, because
  an important distinction among theories is the
  role of top-down contextual information in
  syntactic ambiguity resolution.

11
Fraziers Garden Path Theory

• As you recognize each word, syntactic category is
  input to parsing module.
• Syn cat inputs trigger operation of PS rules.
  When input is consistent with multiple PS rules
• Add new constituent using minimal number of
  nodes. MAS
• Given 2 equally minimal options, attach to
  current constituent. LC
• Pass structure to semantic interpreter.

12
Predictions

• Processing difficulty at point of disambiguation
  whenever minimal attachment (or late closure)
  turns out to be wrong.
• Potential Problem A lot hinges on how you draw
  the trees (i.e., exactly what are the PS rules?)

13
A well-specified (but very specific)
Constraint-based model
The horse raced by
This model predicts local difficulty at the verb
in a reduced relative/main clause ambiguity.
14
Using multiple constraints to resolve syntactic
ambiguities

• Fraziers approach ignores relevant information
  in the interests of reducing processing load
• Constraint-based approaches assume that we have
  the capacity to use constraints from any level of
  representation immediately
• The horse raced past the barn fell.
• The guests invited to the party arrived.
• Is initial NP a better subject or direct object
  of first verb?
• Is there a unique referent for the NP in the
  discourse, or do you need a modifier to tell you
  which horse/guest?
• Is the past tense or the participle more
  frequent, for this verb?

15
How do we get from the words to a sentence-level
representation?

• Word could trigger rules in a phrase structure
  grammar, which generate hierarchical structure
  (as in Fraziers Minimal Attachment approach)
• The Det Det N NP
• Horse N
• Raced V V VP, V NP VP
• The lexicon might actually encode structure, so
  that pieces of PS trees are accessed during word
  recognition and simply pieced together at
  matching nodes. (See Figure 3 of FB,2004)

16
(No Transcript)
17
Most words are associated with multiple trees
I like math.
eat like a pig
friends like mine
18
John ate an apple like...
Which one do you use?
Syntactic ambiguity resolution as lexical
ambiguity resolution.
19
John ate an apple like...
20
Sentence understanding so far

• Syntactic and semantic representations built up
  incrementally
• Garden path sentences
• Difficult, but unambiguous structures
• Fraziers parser is automatic dumb
• Ignoring context/semantics, build simplest
  structure allowed by PS rules
• Constraint-based lexicalist parser is interactive
  and smart
• Use any relevant knowledge to choose best
  structure at point of ambiguity

21
Do Chinese readers use verb transitivity bias to
immediately interpret EC?
Hsieh Boland, in progress

• Judge help ___ rob
• and steal. (Judge help PRO rob and steal)
• de poor people. (Judge help __i rob RC
  peoplei)
• At rob, you must posit an EC, but help allows
  for either PRO (implausible) or trace.
• Transitivity bias of help is cue for analyzing
  EC
• Intransitive/Subject Control reading PRO
• Transitive reading Trace

22
Manipulate transitivity of 1st Verb
PRO Ambig (Intransitive-biased) ???????????
The judge help ? rob and steal The judge
helps to rob and steal. PRO Unambig (Oblig
Intransitive) ??????????? The judge
intend PRO rob and steal The judge intends to
rob and steal. Trace Ambig (Transitive-biased)
??????????? The judge remember ? rob RC
poor people The judge remembers the poor
people who robbed. Trace Unambig (Oblig
Transitive) ??????????? The judge
sympathize-with __ rob RC poor people The
judge sympathizes with the poor people who
robbed.
PRO transitivity bias immediate interp Trace
plausibility
Anomaly
PRO immediate interp Trace transitivity bias
plausibility
No Anomaly
23
Results
Transitivity Bias guides analysis of EC
24
Implications

• As in English (e.g., subject/object
  ambiguity), verb transitivity bias is used to
  guide parsing.
• Verb transitivity cue outweighed plausibility cue
• Because it was more rapidly available?
• Possible that both alternatives were considered
  in ambiguous conditions

25
Syntactic Parallelism Debate

• Lexical semantic knowledge guide selection of
  best analysis at syntactic ambiguity.
• Trueswell (1996)
• The award accepted vs. The thief searched
• Processing costs (garden path) observed if
  structure is later disambiguated in another
  manner.
• Support for the hypothesis that ONE syntactic
  structure selected maintained Serial Account?
• Such findings do rule out full parallelism/delayed
  interpretation

26
Syntactic Parallelism Debate

• Serial accounts must explain why some re-analyses
  are costly and some are not.
• The horse raced past the barn fell.
• Ron believes Rex is a threat. Pritchett, 1992
• Reanalysis costs linked to similarity of
  potential analyses or informativeness of
  disambiguating cue Abney, 1989 Fodor Inoue,
  1994 Konieczny, 1996 Lewis,1998, Pritchett,
  1992
• Ranked parallelism w/costs for re-ranking
  Gibson, 1991 Gorrell, 1987 Hickok, 1993 Tabor
  Hutchins, 2004
• Re-ranking costs predicted by
• Relative support for each analysis
• Digging in effects (Tabor Hutchins, 2004)
• Distinguish between SerialReanalysis accounts
  Limited, Ranked Parallel accounts

27
Hsieh et al. Paper

• Sharon Lucy

28
Hagoort (2008)

• Is brain imaging of use for cognitive theory?
• Fodor does not help to know it happens somewhere
  north of the neck
• Critics focus on fmri
• Cog Neuro toolkit includes ERP MEG, TMS
• Should we be interested in the machinery that
  instantiates human language, or just cognitive
  architecture?
• How does ERP research support the Immediacy
  Assumption (all types of info brought to bear
  immediately)?

29
Syntactic Semantic Processing

• Structure and Interpretation co-vary
• Put (the book) (in the box on the table).
• Put (the book in the box) (on the table).
• Does structural analysis necessarily license
  interpretation?

30
Syntactic Semantic Processing in Tandem

• Constraint-based Lexicalist models (e.g.,
  MacDonald et al., 1994)
• Bolands Concurrent model (1997)
• Kuperberg (2007)

The thief (who was) searched by the police had
weapons. good agent, infreq participle The
award (that was) accepted by the man was
impressive. poor agent, freq participle Initial
attachment of verb to PS tree is influenced by
thematic fit and frequency of alternative verb
forms
31
Bolands Concurrent Theory
The award accepted
award-Theme
Accepted active, past
Agent accepted
Accepted passive, participle
Theme accepted (by)
32
Syntactic Primacy Theories

• Fraziers Garden Path model (1978 later)
• Friedericis 3-Stage Model (e.g., 2002)
• Attach each new constituent to developing phrase
  structure tree
• Lexico-semantic processing thematic role
  assignment
• Syntactic integration revision

33
Testing Parsing Theories

• To what extent does semantic interpretation
  depend upon successful syntactic analysis?

34
Primacy of Syntactic Processing

• Friederici Weissenborn (2007, p. 54) semantic
  integration of words does not take place for
  words which are not syntactically licensed (have
  wrong word category).
• Investigate with ERPs, because different
  components elicited by syntactic
  semantic anomalies.
• A syntactic category violation
• Der Priester wurde vom gebaut
• The priest was by-the built
• read German/French sentence, then judge
  acceptability
• elicits a LAN, followed by a P600, but no
  N400 effects (Friederici et al., 1999, 2004
  Hahne Friederici, 2002, Experiment 1 Hahne
  Jescheniak, 2001 Isel et al., 2007)

35
Bolands Concurrent Theory
Der Priester wurde vom gebaut The priest was
by-the built
Agent
ltNP dative -femgt
vom
36
Counter-evidence ?

• Ainsworth-Darnell, Shulman, Boland (1998)

entrusted lt NP(Theme) PP(Recipient)
gt Control Jill entrusted the recipe to
friends Syntactic Anomaly Jill entrusted the
recipe friends P600 Semantic Anomaly Jill
entrusted the recipe to platforms N400 Double
Anomaly Jill entrusted the recipe platforms
N400 P600
37
Is Syntactic Primacy Universal?

• Zhang, Yu, Boland (under revision)
• In German, syntactic category is well-marked
  (nouns capitalized, case-markings on determiners
  and adjectives, verb tense affixes, agreement
  morphology, etc.)
• Der Priester wurde vom Arbeiter. (expected N)
• Der Priester wurde vom gebaut. (ungrammatical V)
• N400 observed if told to focus on meaning of
  sentence
• In Chinese, syntactic category is not marked by
  morphology on the words themselves
• ???????????????? (expected V peeled)
• ?????????????????(ungrammatical N knife)
• Some theories assume syntactic primacy
  (e.g., Frazier, 1978, Friederici, 2002), others
  do not (e.g., Boland, 1997 Kuperberg, 2007
  MacDonald et al., 1994).

38
Could Syntactic Primacy be a LG-specific
strategy?

• Strongest evidence for Syntactic Primacy comes
  from German.
• In German, syntactic category is well-marked
  (nouns capitalized, case-markings on determiners
  and adjectives, verb tense affixes, agreement
  morphology, etc.)
• Der Priester wurde vom Arbeiter (expected N)
• Der Priester wurde vom gebaut (ungrammatical V)
• N400 is observed if told to focus on meaning
  of sentence
• Zhang, Yu, Boland (under revision)
• In Chinese, syntactic category is not marked by
  inflectional morphology on the words themselves
• ???????????????? (expected V peel)
• ?????????????????(ungram N knife)

39
Stimuli Results

• Correct
• ??/?/?/??/?/??? The girl/ bought/ le (PERF)/
  skirt/ and/ glove.
• (The girl bought a skirt and a glove.)
• Syntactic violation LAN P600
• ??/?/?/?/??/?/???The girl/ bought/ le (PERF)/
  very/ skirt/ and/ glove.
• (The girl bought a very skirt and a glove.)
• Semantic violation N400
• ??/?/?/??/?/??? The girl/ ate/ le (PERF)/
  skirt/ and/ glove.
• (The girl ate a skirt and a glove.)
• Syntactic Semantic violation LAN P600
  N400
• ??/?/?/?/??/?/???The girl/ ate/ le (PERF)/ very
  / skirt/ and/ glove.
• (The girl ate a very skirt and a glove.)
• PERF perfective marker
• Critical word in bold.

Suggests that syntactic semantic processing go
on in parallel
40
Manipulate degree of Semantic violation at
syntactic anomaly
Larger N400 for strong semantic violation
compared to weak semantic violation, despite
syntactic anomaly
41
Difference Map Showing the Scalp Distributions of
the Strong-Weak EffectsView of top of head the
anterior is on top
42
(No Transcript)
43
(No Transcript)
44
Ye, Luo, Friederici, Zhou (2006)
ba construction auditory
N400
sustained anterior negativity (no P600)
sustained anterior negativity (no P600)
N400-like effect
45
Summary Across LGs

• English evidence is mostly consistent with
  syntactic semantic processing in tandem
• French German readers switch between syntactic
  primacy mode interpret anyway mode,
  depending on instructions.
• Chinese stay in interpret anyway mode.
• Can you force Chinese (or English) readers into
  syntactic primacy mode?
• Does Chinese lead to a greater reliance on
  semantic processing than German?
• No reason to favor sentence processing theories
  that maintain syntactic primacy.