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Parsers and Grammars Colin Phillips. Outline The Standard History of Psycholinguistics Parsing and rewrite rules Initial optimism Disappointment and the.

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Presentation on theme: "Parsers and Grammars Colin Phillips. Outline The Standard History of Psycholinguistics Parsing and rewrite rules Initial optimism Disappointment and the."— Presentation transcript:

1 Parsers and Grammars Colin Phillips

2 Outline The Standard History of Psycholinguistics Parsing and rewrite rules Initial optimism Disappointment and the DTC Emergence of independent psycholinguistics Reevaluating relations between competence and performance systems

3 Standard View 324 697+ ? 217 x 32 = ? arithmetic

4 Standard View 324 697+ ? 217 x 32 = ? specialized algorithm arithmetic

5 Standard View 324 697+ ? 217 x 32 = ? specialized algorithm ? something deeper arithmetic

6 Standard View specialized algorithm recursive characterization of well-formed expressions speaking understanding grammatical knowledge, competence language

7 Standard View specialized algorithm recursive characterization of well-formed expressions speaking understanding grammatical knowledge, competence precise but ill-adapted to real-time operation language

8 Standard View specialized algorithm recursive characterization of well-formed expressions speaking understanding grammatical knowledge, competence well-adapted to real-time operation but maybe inaccurate language

9 Grammatical Knowledge How is grammatical knowledge accessed in syntactic computation for... (a) grammaticality judgment (b) understanding (c) speaking Almost no proposals under standard view This presents a serious obstacle to unification at the level of syntactic computation

10

11 Townsend & Bever (2001, ch. 2) “Linguists made a firm point of insisting that, at most, a grammar was a model of competence - that is, what the speaker knows. This was contrasted with effects of performance, actual systems of language behaviors such as speaking and understanding. Part of the motive for this distinction was the observation that sentences can be intuitively ‘grammatical’ while being difficult to understand, and conversely.”

12 Townsend & Bever (2001, ch. 2) “…Despite this distinction the syntactic model had great appeal as a model of the processes we carry out when we talk and listen. It was tempting to postulate that the theory of what we know is a theory of what we do, thus answering two questions simultaneously. 1. What do we know when we know a language? 2. What do we do when we use what we know?

13 Townsend & Bever (2001, ch. 2) “…It was assumed that this knowledge is linked to behavior in such a way that every syntactic operation corresponds to a psychological process. The hypothesis linking language behavior and knowledge was that they are identical.

14 Miller (1962) 1. Mary hit Mark.K(ernel) 2. Mary did not hit Mark. N 3. Mark was hit by Mary.P 4. Did Mary hit Mark?Q 5. Mark was not hit by Mary.NP 6. Didn’t Mary hit Mark?NQ 7. Was Mark hit by Mary?PQ 8. Wasn’t Mark hit by Mary?PNQ

15 Miller (1962) Transformational Cube

16 Townsend & Bever (2001, ch. 2) “The initial results were breathtaking. The amount of time it takes to produce a sentence, given another variant of it, is a function of the distance between them on the sentence cube. (Miller & McKean 1964).” “…It is hard to convey how exciting these developments were. It appeared that there was to be a continuing direct connection between linguistic and psychological research. […] The golden age had arrived.”

17 Townsend & Bever (2001, ch. 2) “Alas, it soon became clear that either the linking hypothesis was wrong, or the grammar was wrong, or both.”

18 Townsend & Bever (2001, ch. 2) “The moral of this experience is clear. Cognitive science made progress by separating the question of what people understand and say from how they understand and say it. The straightforward attempt to use the grammatical model directly as a processing model failed. The question of what humans know about language is not only distinct from how children learn it, it is distinct from how adults use it.”

19 A Simple Derivation S (starting axiom) S

20 A Simple Derivation S (starting axiom) 1. S  NP VP S NPVP

21 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP S NPVP VNP

22 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N S NPVP VNP DN

23 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill S NPVP VNP DN Bill

24 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit S NPVP VNP DN Bill hit

25 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the S NPVP VNP DN Bill hit the

26 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball S NPVP VNP DN Bill hit theball

27 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball S NPVP VNP DN Bill hit theball

28 Reverse the derivation...

29 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball Bill

30 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NP Bill

31 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NP Bill hit

32 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NP VBill hit

33 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NP VBill hit the

34 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NP V D Bill hit the

35 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NP V D Bill hit theball

36 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NP V DN Bill hit theball

37 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NP V DN Bill hit theball

38 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball NPVP VNP DN Bill hit theball

39 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball S NPVP VNP DN Bill hit theball

40 A Simple Derivation S (starting axiom) 1. S  NP VP 2. VP  V NP 3. NP  D N 4. N  Bill 5. V  hit 6. D  the 7. N  ball S NPVP VNP DN Bill hit theball

41 Transformations wh-movement Xwh-NPY 123 --> 2103

42 Transformations VP-ellipsis XVP 1 YVP 2 Z 12345 --> 12305 condition: VP 1 = VP 2

43 Difficulties How to build structure incrementally in right- branching structures How to recognize output of transformations that create nulls

44 Summary Running the grammar ‘backwards’ is not so straightforward - problems of indeterminacy and incrementality Disappointment in empirical tests of Derivational Theory of Complexity Unable to account for processing of local ambiguities

45 Standard View specialized algorithm recursive characterization of well-formed expressions speaking understanding grammatical knowledge, competence language

46 Grammatical Knowledge How is grammatical knowledge accessed in syntactic computation for... (a) grammaticality judgment (b) understanding (c) speaking Almost no proposals under standard view This presents a serious obstacle to unification at the level of syntactic computation

47

48 Arguments for Architecture 1. Available grammars don’t make good parsing devices 2. Grammaticality ≠ Parsability 3. Failure of DTC 4. Evidence for parser-specific structure 5. Parsing/production have distinct properties 6. Possibility of independent damage to parsing/production 7. Competence/performance distinction is necessary, right?

49 Arguments for Architecture 1. Available grammars don’t make good parsing devices 2. Grammaticality ≠ Parsability 3. Failure of DTC 4. Evidence for parser-specific structure 5. Parsing/production have distinct properties 6. Possibility of independent damage to parsing/production 7. Competence/performance distinction is necessary, right?

50 Grammar as Parser - Problems Incremental structure building with PS Rules (e.g. S -> NP VP) –delay –prediction/guessing Indeterminacy ( how to recover nulls created by transformations)

51 Grammar as Parser - Solutions Lexicalized grammars make incremental structure- building much easier (available in HPSG, minimalism, LFG, Categorial Grammar, etc. etc.) sat onthe rug VP -> V PP PP -> P NP VP PP NP P V

52 Grammar as Parser - Solutions Lexicalized grammars make incremental structure- building much easier (available in HPSG, minimalism, LFG, Categorial Grammar, etc. etc.) sat onthe rug sit comp: __ P on comp: __ N VP PP NP P V

53 Grammar as Parser - Solutions Problem of seeking nulls in movement structures

54 Transformations wh-movement Xwh-NPY 123 --> 2103

55 Transformations VP-ellipsis XVP 1 YVP 2 Z 12345 --> 12305 condition: VP 1 = VP 2

56 Grammar as Parser - Solutions Problem of seeking nulls in movement structures …becomes problem of seeking licensing features for displaced phrases, e.g. for wh-phrase, seek Case assigner and thematic role assigner. Requirement to find licensing features is a basic component of all syntactic composition

57 Incremental Structure Building An investigation of the grammatical consequences of incremental, left-to-right structure building

58 Incremental Structure Building A

59 AB

60 A BC

61 A B CD

62 A B C DE

63 AB

64 AB constituent

65 Incremental Structure Building A BC constituent is destroyed by addition of new material

66 Incremental Structure Building A BC

67 A BC constituent

68 Incremental Structure Building A B CD constituent is destroyed by addition of new material

69 Incremental Structure Building the cat

70 Incremental Structure Building the catsat

71 Incremental Structure Building the cat saton

72 Incremental Structure Building the cat sat on the rug

73 Incremental Structure Building the cat saton

74 Incremental Structure Building the cat sat on the rug

75 Incremental Structure Building the cat sat on the rug [sat on] is a temporary constituent, which is destroyed as soon as the NP [the rug] is added.

76 Incremental Structure Building Conflicting Constituency Tests Verb + Preposition sequences can undergo coordination… (1) The cat sat on and slept under the rug. …but cannot undergo pseudogapping (Baltin & Postal, 1996) (2) *The cat sat on the rug and the dog did the chair.

77 Incremental Structure Building the cat saton

78 Incremental Structure Building the cat satonsleptunder and

79 Incremental Structure Building the cat satonsleptunder and coordination applies early, before the V+P constituent is destroyed.

80 Incremental Structure Building the cat saton

81 Incremental Structure Building the cat sat on the rug

82 Incremental Structure Building the cat sat on the rug andthe dogdid

83 Incremental Structure Building the cat sat on the rug andthe dogdid pseudogapping applies too late, after the V+P constituent is destroyed.

84 Incremental Structure Building Constituency Problem Different diagnostics of constituency frequently yield conflicting results Incrementality Hypothesis (a) Structures are assembled strictly incrementally (b) Syntactic processes see a ‘snapshot’ of a derivation - they target constituents that are present when the process applies (c) Conflicts reflect the simple fact that different processes have different linear properties Applied to interactions among binding, movement, ellipsis, prosodic phrasing, clitic placement, islands, etc. (Phillips 1996, in press; Richards 1999, 2000; Guimaraes 1999; etc.)

85 Interim Conclusion Grammatical derivations look strikingly like the incremental derivations of a parsing system But we want to be explicit about this, so...

86 Computational Modeling (Schneider 1999; Schneider & Phillips, 1999)

87

88 Arguments for Architecture 1. Available grammars don’t make good parsing devices 2. Grammaticality ≠ Parsability 3. Failure of DTC 4. Evidence for parser-specific structure 5. Parsing/production have distinct properties 6. Possibility of independent damage to parsing/production 7. Competence/performance distinction is necessary, right?

89 Townsend & Bever (2001, ch. 2) “Linguists made a firm point of insisting that, at most, a grammar was a model of competence - that is, what the speaker knows. This was contrasted with effects of performance, actual systems of language behaviors such as speaking and understanding. Part of the motive for this distinction was the observation that sentences can be intuitively ‘grammatical’ while being difficult to understand, and conversely.”

90 Grammaticality ≠ Parsability “It is straightforward enough to show that sentence parsing and grammaticality judgments are different. There are sentences which are easy to parse but ungrammatical (e.g. that-trace effects), and there are sentences which are extremely difficult to parse, but which may be judged grammatical given appropriate time for reflection (e.g. multiply center embedded sentences). This classic argument shows that parsing and grammar are not identical, but it tells us very little about just how much they have in common.” (Phillips, 1995)

91 Grammaticality ≠ Parsability Grammatical sentences that are hard to parse –The cat the dog the rat bit chased fled –John gave the man the dog bit a sandwich Ungrammatical sentences that are understandable –Who do you think that left? –The children is happy –The millionaire donated the museum a painting

92 Grammaticality ≠ Parsability Grammatical sentences that are hard to parse –The cat the dog the rat bit chased fled –John gave the man the dog bit a sandwich Can arise independent of grammar –Resource (memory) limitations –Incorrect choices in ambiguity

93 (Preliminary) Incomplete structural dependencies have a cost (that’s what yields center embedding)

94 A Contrast (Gibson 1998) Relative Clause within a Sentential Complement (RC  SC): The fact [ CP that the employee [ RC who the manager hired] stole office supplies] worried the executive. Sentential Complement within a Relative Clause (SC  RC): #The executive [ RC who the fact [ CP that the employee stole office supplies] worried] hired the manager. RC  SC is easier to process than SC  RC

95 A Contrast (Gibson 1998) Relative Clause within a Sentential Complement (RC  SC): [ SC that the employee [ RC who the manager hired] stole Sentential Complement within a Relative Clause (SC  RC): [ RC who the fact [ SC that the employee stole office supplies] worried] RC  SC is easier to process than SC  RC

96 A Contrast (Gibson 1998) Relative Clause within a Sentential Complement (RC  SC): [ SC that the employee [ RC who the manager hired] stole Sentential Complement within a Relative Clause (SC  RC): [ RC who the fact [ SC that the employee stole office supplies] worried] RC  SC is easier to process than SC  RC

97 A Contrast (Gibson 1998) Relative Clause within a Sentential Complement (RC  SC): [ SC that the employee [ RC who the manager hired] stole Sentential Complement within a Relative Clause (SC  RC): [ RC who the fact [ SC that the employee stole office supplies] worried] Contrast is motivated by off-line complexity ratings

98 Grammaticality ≠ Parsability Ungrammatical sentences that are understandable –Who do you think that left? –The children is happy –The millionaire donated the museum a painting System can represent illegal combinations (e.g. categories are appropriate, but feature values are inappropriate) Fact that understandable errors are (i) diagnosable, (ii) nearly grammatical, should not be overlooked

99 Grammaticality ≠ Parsability Are the parser’s operations fully grammatically accurate?

100 Standard View specialized algorithm recursive characterization of well-formed expressions speaking understanding grammatical knowledge, competence well-adapted to real-time operation but maybe inaccurate language

101 Grammatical Accuracy in Parsing The grammar looks rather like a parser BUT, does the parser look like a grammar? i.e., are the parser’s operations fully grammatically accurate at every step … even in situations where such accuracy appears quite difficult to achieve (Phillips & Wong 2000)

102 Self-Paced Reading -- --- ------- ------- ---- --- ----. (e.g. Phillips & Wong 2000)

103 We --- ------- ------- ---- --- ----. (e.g. Phillips & Wong 2000) Self-Paced Reading

104 -- can ------- ------- ---- --- ----. (e.g. Phillips & Wong 2000) Self-Paced Reading

105 -- --- measure ------- ---- --- ----. (e.g. Phillips & Wong 2000) Self-Paced Reading

106 -- --- ------- reading ---- --- ----. (e.g. Phillips & Wong 2000) Self-Paced Reading

107 -- --- ------- ------- time --- ----. (e.g. Phillips & Wong 2000) Self-Paced Reading

108 -- --- ------- ------- ---- per ----. (e.g. Phillips & Wong 2000) Self-Paced Reading

109 -- --- ------- ------- ---- --- word. (e.g. Phillips & Wong 2000) Self-Paced Reading

110 Grammatical Accuracy in Parsing Wh-Questions (Phillips & Wong 2000)

111 Grammatical Accuracy in Parsing Wh-Questions Englishmen cook wonderful dinners. (Phillips & Wong 2000)

112 Grammatical Accuracy in Parsing Wh-Questions Englishmen cook wonderful dinners. (Phillips & Wong 2000)

113 Grammatical Accuracy in Parsing Wh-Questions Englishmen cook what (Phillips & Wong 2000)

114 Grammatical Accuracy in Parsing Wh-Questions Englishmen cook what (Phillips & Wong 2000)

115 Grammatical Accuracy in Parsing Wh-Questions What do Englishmen cook (Phillips & Wong 2000)

116 Grammatical Accuracy in Parsing Wh-Questions What do Englishmen cook gap (Phillips & Wong 2000)

117 Grammatical Accuracy in Parsing Wh-Questions What do Englishmen cook gap  (Phillips & Wong 2000)

118 Grammatical Accuracy in Parsing Long-distance Wh-Questions Few people think that anybody realizes that Englishmen cook wonderful dinners (Phillips & Wong 2000)

119 Grammatical Accuracy in Parsing Long-distance Wh-Questions Few people think that anybody realizes that Englishmen cook what (Phillips & Wong 2000)

120 Grammatical Accuracy in Parsing Long-distance Wh-Questions What do few people think that anybody realizes that Englishmen cook gap  (Phillips & Wong 2000)

121 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ The plan to remove the equipment ultimately destroyed the building. (Phillips & Wong 2000)

122 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ The plan to remove the equipment ultimately destroyed the building. Direct Object NP (Phillips & Wong 2000)

123 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ The plan to remove the equipment ultimately destroyed the building. Direct Object NP Main Clause (Phillips & Wong 2000)

124 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ The plan to remove the equipment ultimately destroyed the building. Direct Object NP Main Clause Subject NP Embedded Clause (Phillips & Wong 2000)

125 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove the equipment ultimately destroy (Phillips & Wong 2000)

126 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove the equipment ultimately destroy gap  (Phillips & Wong 2000)

127 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove ultimately destroy the building (Phillips & Wong 2000)

128 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove gap ultimately destroy the building  (Phillips & Wong 2000)

129 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove gap ultimately destroy the building  Subject Island Constraint A wh-phrase cannot be moved out of a subject. (Phillips & Wong 2000)

130 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove ultimately destroy (Phillips & Wong 2000)

131 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove ultimately destroy (Phillips & Wong 2000)

132 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove ultimately destroy  Parasitic Gap Generalization: the good gap ‘rescues’ the bad gap

133 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan to remove ultimately destroy  Generalization: the good gap ‘rescues’ the bad gap Infinitive

134 Grammatical Accuracy in Parsing ‘Parasitic Gaps’ What did the plan that removed ultimately destroy  Revised Generalization (informal) Only mildly bad gaps can be rescued by good gaps. Finite 

135 Grammaticality Ratings Ratings from 50 subjects

136 Grammatical Accuracy in Parsing A ‘Look-Ahead’ Problem What did the plan to remove ultimately destroy  Infinitive The good gap rescues the bad gap BUT The bad gap appears before the good gap … a look-ahead problem

137 Grammatical Accuracy in Parsing A ‘Look-Ahead’ Problem What did the plan to remove ultimately destroy  Infinitive Question When the parser reaches the embedded verb, does it construct a dependency - even though the gap would be a ‘bad’ gap? Embedded Verb

138 Grammatical Accuracy in Parsing A ‘Look-Ahead’ Problem What did the plan to remove ultimately destroy  Infinitive Risky What did the plan that removed ultimately destroy  Finite  Reckless

139 Grammatical Accuracy in Parsing Question What do speakers do when they get to the verb embedded inside the subject NP? (i) RISKY: create a gap in infinitival clauses only - violates a constraint, but may be rescued (ii) RECKLESS: create a gap in all clause types - violates a constraint; cannot be rescued (iii) CONSERVATIVE: do not create a gap (Phillips & Wong 2000)

140 a.…what … infinitival verb...[infinitive, gap ok] b.… whether..infinitival verb...[infinitive, no gap] c.… what … finite verb...[finite, gap not ok] d. … whether … finite verb...[finite, no gap] Grammatical Accuracy in Parsing Materials (Phillips & Wong 2000)

141 a.…what … infinitival verb...[infinitive, gap ok] b.… whether..infinitival verb...[infinitive, no gap] c.… what … finite verb...[finite, gap not ok] d. … whether … finite verb...[finite, no gap] Grammatical Accuracy in Parsing Materials Gap here: RISKY (Phillips & Wong 2000)

142 a.…what … infinitival verb...[infinitive, gap ok] b.… whether..infinitival verb...[infinitive, no gap] c.… what … finite verb...[finite, gap not ok] d. … whether … finite verb...[finite, no gap] Grammatical Accuracy in Parsing Materials Gap here: RECKLESS (Phillips & Wong 2000)

143 a.The outspoken environmentalist worked to investigate what the local campaign to preserve the important habitats had actually harmed in the area that the birds once used as a place for resting while flying south. [infinitive, gap] b.…whether the local campaign to preserve… [infinitive, no gap] c.…what the local campaign that preserved… [finite, gap] d.…whether the local campaign that preserved … [finite, no gap] Grammatical Accuracy in Parsing Materials (Phillips & Wong 2000)

144 Grammatical Accuracy in Parsing What did the plan to remove ultimately destroy  Infinitive Risky (Phillips & Wong 2000)

145 Grammatical Accuracy in Parsing What did the plan that removed ultimately destroy  Finite  Reckless (Phillips & Wong 2000)

146 Grammatical Accuracy in Parsing Conclusion Structure-building is extremely grammatically accurate, even when the word-order of a language is not cooperative Constraints on movement are violated in exactly the environments where the grammar allows the violation to be forgiven (may help to explain discrepancies in past studies) Such accuracy is required if grammatical computation is to be understood as real-time on-line computation

147

148 Arguments for Architecture 1. Available grammars don’t make good parsing devices 2. Grammaticality ≠ Parsability 3. Failure of DTC 4. Evidence for parser-specific structure 5. Parsing/production have distinct properties 6. Possibility of independent damage to parsing/production 7. Competence/performance distinction is necessary, right?

149 Derivational Theory of Complexity ‘The psychological plausibility of a transformational model of the language user would be strengthened, of course, if it could be shown that our performance on tasks requiring an appreciation of the structure of transformed sentences is some function of the nature, number and complexity of the grammatical transformations involved.’ (Miller & Chomsky 1963: p. 481)

150 Miller (1962) 1. Mary hit Mark.K(ernel) 2. Mary did not hit Mark. N 3. Mark was hit by Mary.P 4. Did Mary hit Mark?Q 5. Mark was not hit by Mary.NP 6. Didn’t Mary hit Mark?NQ 7. Was Mark hit by Mary?PQ 8. Wasn’t Mark hit by Mary?PNQ

151 Miller (1962) Transformational Cube

152 Derivational Theory of Complexity Miller & McKean (1964): Matching sentences with the same meaning or ‘kernel’ Joe warned the old woman.K The old woman was warned by Joe.P1.65s Joe warned the old woman.K Joe didn’t warn the old woman.N1.40s Joe warned the old woman.K The old woman wasn’t warned by Joe.PN3.12s

153 McMahon (1963) a.i. seven precedes thirteenK (true) ii. thirteen precedes sevenK (false) b.i. thirteen is preceded by sevenP (true) ii. seven is preceded by thirteenP (false) c.i. thirteen does not precede sevenN (true) ii. seven does not precede thirteenN (false) d.i. seven is not preceded by thirteenPN (true) ii. thirteen is not preceded by sevenPN (false)

154 Easy Transformations Passive –The first shot the tired soldier the mosquito bit fired missed. –The first shot fired by the tired soldier bitten by the mosquito missed. Heavy NP Shift –I gave a complete set of the annotated works of H.H. Munro to Felix. –I gave to Felix a complete set of the annotated works of H.H. Munro. Full Passives –Fido was kissed (by Tom). Adjectives –The {red house/house which is red} is on fire.

155 Failure of DTC? Any DTC-like prediction is contingent on a particular theory of grammar, which may be wrong It’s not surprising that transformations are not the only contributor to perceptual complexity –memory demands, may increase or decrease –ambiguity, where grammar does not help –difficulty of access

156

157 Arguments for Architecture 1. Available grammars don’t make good parsing devices 2. Grammaticality ≠ Parsability 3. Failure of DTC 4. Evidence for parser-specific structure 5. Parsing/production have distinct properties 6. Possibility of independent damage to parsing/production 7. Competence/performance distinction is necessary, right?

158 Garden Paths & Temporary Ambiguity –The horse raced past the barn fell. –Weapons test scores a hit. –John gave the man the dog bit a sandwich. Grammar can account for the existence of global ambiguities (e.g. ‘Visiting relatives can be boring’), but not local ambiguities … since the grammar does not typically assemble structure incrementally

159 Garden Paths & Temporary Ambiguity Ambiguity originally studied as test of solution to the incrementality problem Heuristics & Strategies (e.g. Bever, 1970) –NP V => subject verb –V NP => verb object –V NP NP => verb object object Garden paths used as evidence for effects of heuristics

160 Garden Paths & Temporary Ambiguity Heuristics & Strategies –NP V => subject verb The horse raced past the barn fell –V NP => verb object The student knew the answer was wrong –V NP NP => verb object object John gave the man the dog bit a sandwich

161 Ambiguity Resolution Observation: ‘heuristics’ miss a generalization about how ambiguities are preferentially resolved Kimball (1973): Seven principles of surface structure parsing (e.g. Right Association) Frazier (1978), Fodor & Frazier (1978): Minimal Attachment, Late Closure Various others, much controversy...

162 Ambiguity Resolution Assumptions –grammatical parses are accessed (unclear how) –simplest analysis of ambiguity chosen (uncontroversial) –structural complexity affects simplicity (partly controversial) –structural complexity determines simplicity (most controversial)

163 Ambiguity Resolution Relevance to architecture of language –Comprehension-specific heuristics which compensate for inadequacy of grammar imply independent system –Comprehension-specific notions of structural complexity compatible with independent system If grammar says nothing about ambiguity, and structural complexity is irrelevant to ambiguity resolution, as some argue, then ambiguity is irrelevant to question of parser-grammar relations.

164

165 Arguments for Architecture 1. Available grammars don’t make good parsing devices 2. Grammaticality ≠ Parsability 3. Failure of DTC 4. Evidence for parser-specific structure 5. Parsing/production have distinct properties 6. Possibility of independent damage to parsing/production 7. Competence/performance distinction is necessary, right?

166 Parsing ≠ Production Parsing generates meaning from form Production generates form from meaning Different ‘bottlenecks’ in the two areas –garden paths in comprehension –word-category constraint in production errors –etc., etc. Lexical access: speaking and recognizing words differs, but do we assume that this reflects different systems? Contemporary production theories are now incremental structure-building systems, more similar to comprehension models

167

168 Arguments for Architecture 1. Available grammars don’t make good parsing devices 2. Grammaticality ≠ Parsability 3. Failure of DTC 4. Evidence for parser-specific structure 5. Parsing/production have distinct properties 6. Possibility of independent damage to parsing/production 7. Competence/performance distinction is necessary, right?

169 Competence & Performance Different kinds of formal systems: ‘Competence systems’ and ‘Performance systems’ The difference between what a system can generate given unbounded resources, and what it can generate given bounded resources The difference between a cognitive system and its behavior

170 Competence & Performance (1) It’s impossible to deny the distinction between cognitive states and actions, the distinction between knowledge and its deployment. (2) How to distinguish ungrammatical-but-comprehensible examples (e.g. John speaks fluently English) from hard-to- parse examples. (3) How to distinguish garden-path sentences (e.g. The horse raced past the barn fell) from ungrammatical sentences. (4) How to distinguish complexity overload sentences (e.g. The cat the dog the rat chased saw fled) from ungrammatical sentences.

171 Competence & Performance “It is straightforward enough to show that sentence parsing and grammaticality judgments are different. There are sentences which are easy to parse but ungrammatical (e.g. that-trace effects), and there are sentences which are extremely difficult to parse, but which may be judged grammatical given appropriate time for reflection (e.g. multiply center embedded sentences). This classic argument shows that parsing and grammar are not identical, but it tells us very little about just how much they have in common.” (Phillips, 1995) This argument is spurious!

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173 Summary Motivation for combining learning theories with theories of adult knowledge is well-understood; much more evidence needed. Theories of comprehension and production long thought to be independent of ‘competence’ models. In fact, combination of these is quite feasible; if true, possible to investigate linguistic knowledge in real time.


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