Transcript BRIEFING TITLE - ALL CAPS 30 Jan 01

Double R Theory
January 2011
Jerry Ball
Human Effectiveness Directorate
711th Human Performance Wing
Air Force Research Laboratory
Theoretical Foundations
Language Representation and Processing
•
Double R Grammar
– Cognitive Linguistic theory of the grammatical
encoding of referential and relational meaning
•
Double R Process
– Psycholinguistic theory of the processing of
English text into Double R Grammar based
representations
•
Double R Model
– Computational implementation using the ACT-R
cognitive architecture and modeling environment
DoubleRTheory.com
2
Theoretical Foundations
Language Representation and Processing
•
Double R Grammar
– Cognitive Linguistic theory of the grammatical
encoding of referential and relational meaning
•
Double R Process
– Psycholinguistic theory of the processing of
English text into Double R Grammar based
representations
•
Double R Model
– Computational implementation using the ACT-R
cognitive architecture and modeling environment
DoubleRTheory.com
3
Theoretical Foundations
Grounding Language in Experience
• Symbol Grounding (Harnad)
– Ungrounded symbols are meaningless
– There must be a chain from abstract to perceptually grounded
concepts that provides the grounding for abstract concepts
• Perceptual Symbol Systems (Barsalou)
– No purely abstract concepts
– The brain is a highly evolved perceptual (motor) organ
– Imagery simulates perceptual experience
•
Embodied Cognition (Lakoff et al.)
– Abstract concepts are often understood via metaphorical
association with more concrete concepts
• Good is up—Bad is down; Life is a journey
4
Theoretical Foundations
Situation Model
•
Situation Model (Kintsch et al.)
– Originally viewed as a propositional text base (van
Dijk & Kintsch)
• Elaboration of propositions in linguistic input
– Now viewed as a Spatial-Imaginal (and Temporal)
representation of the objects and situations
described by linguistic expressions and encoded
directly from the environment (Zwann et al.)
• Non-propositional (in part)
• Non-textual
• No available computational implementations
– Provides grounding for linguistic representations
5
Abstract Concepts vs. Perceptually
Grounded Language
The Prevailing “Cognitive Psychological” View
Real World
Mental Box
Perception
“pilot”
Cognition
“pilot”
XY-123
(aka PILOT)
Concept ~ abstract
amodal fixed point in
conceptual space
6
Abstract Concepts vs. Perceptually
Grounded Language
An Emerging “Embodied Cognition” View
Real World
“pilot”
perception
(Perceptual)
Do we really need
abstract concepts?
How are they learned?
“pilot”
grounding
Explicit
Mental Box
Perceptual
Symbol
Cognition is the
simulation of
perceptual experience
perception
Concept ~ dynamic and
tangled interconnections
of associated experiences
7
Language is Grounded in a
Situation Model
SRE: Situation Referring Expression
ORE: Object Referring Expression
PRED: Predicate
ORE
The horse runs
refers
the
subj
horse
SRE
head
PRED
runs
refers
Dynamic mental simulation of horse running would be better!
8
Language is Grounded in a
Situation Model
The paint runs
ORE
the
Each experience of a
running event changes the
RUN concept!
refers
subj
paint
SRE
head
PRED
runs
refers
Dynamic mental simulation of paint running would be better!
9
Guiding Linguistic Principles
•
Jackendoff’s (1983) Grammatical Constraint:
…one should prefer a semantic theory that explains
otherwise arbitrary generalizations about the syntax
and the lexicon…a theory’s deviations from efficient
encoding must be vigorously justified, for what appears
to be an irregular relationship between syntax and
semantics may turn out merely to be a bad theory of
one or the other
10
Guiding Linguistic Principles
•
Langacker’s Cognitive Grammar (1987, 1991)
– Grammar is simply the structuring and
symbolization of semantic content
– Exclusionary Fallacy – one analysis, motivation,
categorization, cause, function or explanation for a
linguistic phenomenon necessarily precludes
another
– Rule/List Fallacy – the assumption, on grounds of
simplicity, that particular statements (i.e. lists) must
be excised from the grammar of a language if
general statements (i.e. rules) that subsume them
can be established
11
Construction Grammar
(Fillmore, Goldberg, Sag, etc.)
•
Constructions—the basic units of grammar—
are pairings of form, function and meaning
form
the man
function
subject predicator object
meaning
HIT(AGENT:MAN PATIENT:BALL)
semantic roles
hit
the ball
“concepts”
uppercase word syndrome
12
Construction Grammar
• Declarative Clause + Intransitive Verb construction
– The woman sneezed
• Decl Clause + Transitive Verb construction
– The man hit the ball
• Wh-Question + Ditransitive Verb + Passive constr.
– Who was given the ball?
• Decl Clause + Intrans Verb + Causative constr.
– The woman sneezed the napkin off the table
13
X-Bar Theory
•
Key element of Chomsky’s Generative Grammar
from the 1970’s to the 1990’s
•
Theory of the universal structure of all languages
– Autonomous from meaning
•
•
X-Bar structure presumed to be innate (not learned)
•
Has gone thru several major revisions resulting in
more and more complex syntactic representations
•
Subsumed by other theoretical considerations in
Chomsky’s Minimalist Program (circa. 1995)
Replaced Phrase Structure Grammar component of
earlier theory (e.g. S  NP VP; NP  Det N; …)
14
X-Bar Theory (Chomsky 1970)
Universal structure of all
languages except that
relative locations can vary
(e.g. complements may
occur before or after head)
Specifier
XP
X-Bar
X
(head)
Universal structure of all
languages – very strong claim
– generative linguists spent
next 20+ years trying to
demonstrate it!
Generalization over
Syntactic Categories
– NP, VP, AP, PP
Complement(s)
XP  Spec X-Bar
X-Bar  X (Head) Comp(s)
15
X-Bar Theory ~ 1993
Universal structure of all
languages  Something
went seriously wrong!
Locally adheres to X-Bar
Schema  Globally very
complex!
XP
(X’’)
Spec
X-Bar
(X’)
X
Comp
(YP)
X-Bar schema
Universal structure of clause
16
X-Bar Theory
(adapted in Ball 2007)
What’s right about X-Bar Theory:
1. Referential layer
2. Relational layer
3. Grammatical functions: specifier, head,
complement, modifier (but need to be
semantically motivated)
Generalization over
grammatical categories –
referring expression
XP
complements – arguments of
relational head
referential
layer
Specifier
specifier – indicates referential
function
X-Bar
X
(head)
Complement(s)
relational
layer
head – semantically most significant element
17
Simpler Syntax
(Culicover & Jackendoff 2005)
• Reaction against the complex syntactic
representations of modern mainstream generative
grammar
– Against syntactocentrism
•
If there is a level of meaning representation, then
syntactic representations can be simpler
– Flat as opposed to deeply nested syntactic
representations
•
Culicover & Jackendoff are former students of
Chomsky
18
Comprehensive Grammars of
English
• Cambridge Grammar (Huddleston & Pullum, 2002)
– Informed by linguistic theory, but attempts to
cover most of English with all its exceptions
– Adds functional categories to syntactic
representations
•
Longman’s Grammar (Quirk et al., 1985)
– Focus on basic functions of linguistic elements
– In the spirit of Functional Grammar as opposed to
Chomsky’s Generative Grammar
19
Double R Grammar
•
Theory of the grammatical encoding of Referential
and Relational meaning
•
Derived from X-Bar Theory prior to the introduction
of functional heads (Chomsky, 1970)
• Grammatical Functions (GFs) explicitly represented
– Phrase Level: Specifier, Head, Complement, Modifier
– Clause Level: Specifier, Head, Subject (Comp), Modifier
• Specifier + Head  Referring Expression (Max Proj)
– All the grammatical info needed to support reference
• Specifier = locus of Referential meaning
• Head = locus of Relational meaning
20
Basic Nominal – X-Bar Theory
(Chomsky 1970)
NP  D N-Bar
N-Bar  N
the captain
Maximal Projection
NP
Syntactic Category
D
N-Bar
Head (implicit)
Specifier (implicit)
N
Later – D reanalyzed
as head of DP
(functional head)
DP  D-bar NP
the
Lexical Item
captain
• Noun is head of nominal (NP)
• N-bar level is required
Grammatical Functions are implicit in syntactic representation
21
Basic Nominal – Simpler Syntax
NP  D N (head)
the captain
Double Line
marks head
Syntactic Category
NP
D
N
Lexical Item
the
One (explicit) phrase level GF:
1. Head
captain
• Noun is head of nominal (NP)
• No N-bar level
22
Basic Nominal – Cambridge
Grammar
NP  Det:D Head:N
the captain
NP
Det:
D
Head:
N
GF:
Syntactic Category
Lexical Item
the
Four phrase level (NP) GF’s:
1. Head
2. Determiner
3. Complement
4. Modifier
captain
• Noun is head of nominal (NP)
• N-Bar level allowed, but not required
Note: Nominal = N-bar, not NP
for H&P
23
Nominal ~ Referring Expression
John Lyons, Semantics, Vol 2, 1977, p. 445
“Looked at from a semantic point of view, nominals
are referring expressions”
“They are expressions which have a certain
potential for reference”
24
Basic Nominal – Double R
ORE  Spec Head; Spec  D; Head  N
the captain
Object Referring Expression (ORE)
Grammatical/
Lexical
Construction
Spec
Head
D
N
Grammatical
Function (GF)
Lexical Item
the
captain
Referential pole
Four phrase level GF’s:
1. Head
2. Specifier
3. Complement
4. Modifier
Relational pole
• Nominal ~ Object Referring Expression
• Noun is head of nominal (NP)
• No N-bar level
25
Basic Clause
X-Bar Theory ~ 1970s
S  NP VP
VP  Specv V-Bar
V-Bar  V
Joe runs
S
Deep Structure
NP
N-bar
N
Joe
Structure of S
not explained
by X-Bar Theory
circa. 1970
-- no specifier or head of S
VP
Specv
TENSEpres
V-bar
V
run
Deep Structure gets transformed
into Surface Structure
(Transformational Grammar)
-- TENSEpres + run  runs
26
Basic Clause – Simpler Syntax
S  NP AUX VP
Joe runs
S
NP
AUX
VP
N
TENSEpres
V
Syntactic Tier:
Joe
Clause level GF’s:
1. Subject
2. Object
3. Second Object
run
affix hopping
GF Tier:
Subject
CS:
RUN(AGENT:X)
Vestige of
Transformational Grammar
• Head of S not specified in Culicover (2009)
• In Jackendoff (2002), no lexical items in syntactic tier
27
Basic Clause – Cambridge Grammar
Clause  Subj:NP Predicate:VP
Predicate:VP  Predicator:V
Clause
Joe runs
Subj:
NP
Predicate:
VP
Head:
N
Predicator:
V
Joe
runs
Clause level GF’s:
1. Predicate ~ Head of Clause
2. Subject ~ External Complement
3. Modifier
Additional phrase level (VP) GF:
1. Predicator ~ Head of VP
No equivalent to determiner at clause level!
28
Basic Clause – Double R
SRE  Subj (Spec+)Head
Joe runs
Subj  ORE
(Spec+)Head  Vfin
Situation Referring Expression (SRE)
Grammatical
Construction
Subj
|
(Spec+)Head
ORE
|
(Spec+)Head
|
PN
|
Joe
Clause level GF’s:
1. Head
2. Specifier
3. Subject ~ External Complement
4. Modifier
Vfin
|
runs
• SRE ~ Clause or S
Specification fused with Head
29
Basic Clause
X-Bar Theory ~ 1970s
S  NP VP
VP  Specv V-Bar (head)
V-Bar  V (head) NP (comp)
NP  D (spec) N-bar (head)
N-Bar  N (head)
NP
|
Later – VP reanalyzed as
N-bar
head of S & Subject NP
|
reanalyzed as
N
specifier of S – left of
head so must be spec!
|
S  NP (spec) VP (head)
Joe
Joe kicks the ball
S
VP
Specv
TENSEpres
Later – tense reanalyzed as head of IP;
S reanalyzed as CP (complementizer phrase) with C-bar = IP
CP  IP = C-bar (head)
IP (inflection phrase)  NP (spec) I-bar (head)
I-bar  I (tense head) VP (comp)
V-Bar
V
|
kick
NP
D
|
the
N-bar
|
N
|
ball
30
Basic Clause – X-Bar Theory ~
1980s
CP  IP = C-bar (head)
IP  NP (spec) I-bar (head)
I-bar  I (head) VP (comp)
VP  V-Bar (head) NP (comp)
V-Bar  V (head)
Spec of IP
(subject)
CP
IP = C-bar
I-bar
NP
|
I
N-bar
|
|
N TENSEpres
|
Joe
Later – additional levels proposed:
AgrP (agreement)  AgrSP, AgrOP
Head of CP
NegP (negation)
ModP (modality)
Etc.
Sentence now adheres to X-Bar Theory!
Joe kicks the ball
Complement of I-bar
VP
V-Bar
V
|
kick
NP
D
|
the
N-bar
|
N
|
ball
31
Basic Clause – X-Bar Theory ~ 1993
Joe kicks the ball
C’ = C-bar
Subj Agreement
|
Joe?
Some languages
have object
agreement, so
universal, innate
structure must
have this layer!
TP = IP
Obj Agreement
TENSEpres
Universal clausal structure
of all languages!
kick the ball
VP way down
here!
Structure below
VP not shown
32
Basic Clause – Simpler Syntax
S  NP AUX VP
VP  V (head) NP
Syntactic Tier:
Joe kicks the ball
S
NP
AUX
VP
||
||
N TENSEpres V
|
|
Joe
kick
affix hopping
GF Tier:
Subject
CS:
KICK(AGENT:X
NP
D
|
the
N
|
ball
Object
PATIENT:Y )
33
Basic Clause – Cambridge Grammar
Clause  Subj:NP Predicate:VP
Predicate:VP  Predicator:V Obj:NP
Joe kicks the ball
Clause
Subj:
NP
|
Head:
N
|
Joe
Predicate:
VP
Predicator:
V
|
kicks
Additional phrase level (VP) GF:
1. Object ~ Complement
Obj:
NP
Det:
D
|
the
Head:
N
|
ball
34
Basic Clause – Double R
SRE  Subj (Spec+)Head
Subj  ORE
Head  Pred-Trans-Verb
PTV  Head Obj
Subj
|
ORE
|
(Spec+)Head
|
PN
|
Joe
Additional phrase level GF:
1. Object ~ Complement
Joe kicks the ball
SRE
(Spec+)Head
|
Pred-Trans-Verb
(Spec+)Head
|
Vfin
|
kicks
Spec
|
D
|
the
Grammatical
Construction
Obj
|
ORE
Head
|
N
|
ball
35
Basic Clause with Auxiliary –
Simpler Syntax
S  NP AUX VP
VP  V (head) NP
Syntactic Tier:
Joe is kicking the ball
S
NP
||
N
|
Joe
AUX
VP
[PROG-PART]
TENSEpres
VAUX
|
be
||
V
|
kick
affix hopping
GF Tier:
Subject
CS:
KICK(AGENT:X
NP
[PROG-PART]
Object
D
|
the
N
|
ball
PATIENT:Y )
36
Basic Clause with Auxiliary –
Cambridge Grammar
Clause
Subj:
NP
|
Head:
N
|
Joe
Predicate:
VP
Predicator:
V
|
is
Clause  Subj:NP Pred:VP
Pred:VP  Pred-or:V Comp:Clausebare
Comp:Clausebare  Pred:VP
Pred:VP  Pred-or:V Obj:NP
Comp:
Clausebare
|
Predicate:
VP
head of
clause!
Predicator:
V
catenative verbs
bare clause
(no subj or tense)
No specifier GF
Obj:
NP
|
kicking
Joe is kicking the ball
Det:
D
Head:
N
|
|
the
ball
37
Basic Clause with Auxiliary –
Double R
SRE
Subj
|
ORE
|
Head
|
N
|
Joe
Spec
|
Aux
|
is
head of
clause
Joe is kicking the ball
Head
|
Pred-Trans-Verb
Head
|
V
|
kicking
SRE  Subj Spec Head
Subj  ORE
Spec  Aux
Head  Pred-Trans-Verb
PTV  Head Obj
Obj
|
ORE
Spec
|
D
|
the
Head
|
N
|
ball
38
Possessive Nominal –
Simpler Syntax
NP  NP’s N
Joe’s book
NP
No label!
NP
Joe
’s
N
book
39
Possessive Nominal –
Cambridge Grammar
Joe’s book
NPPlain Subj+Det:NPGen Head:N
Fused subject-determiner
Additional phrase level GF:
1. Subj ~ Complement
NPPlain
Subj+Det:
NPGen
Head:
N
Joe’s
book
H & P allow GF’s to be fused
– consistent with grammatical evidence
40
Possessive Nominal –
Double R
Joe’s book
Poss-ORE  RefPt+Spec Head
Possessive Object Referring
Expression (ORE)
RefPt
Spec
ORE –
(Spec+)Head –
PN
Poss-Mkr
Joe
’s
Referential pole
Grammatical
Construction
Head
N
book
Relational pole
Additional phrase level GF:
1. Ref Pt ~ Complement
41
Clause without Main Verb –
Simpler Syntax
S  NP AUX PP
the book is on the table
S
NP
AUX
Syntactic Tier:
D
|
the
GF Tier:
CS Tier:
N TENSEpres
|
book
VAUX
|
be
Subject
PP
||
P
|
on
NP
D
|
the
N
|
table
BE(THEME:X, ON(THEME:Y))
42
Clause without Main Verb –
Cambridge Grammar
Clause  Subj:NP Pred:VP
Pred:VP  Pred-or:V Comp:PP
Comp:PP  Head:P Obj:NP
the book is on the table
Clause
Predicate:
VP
Subj:
NP
Det:
D
|
the
Head:
N
|
book
Predicator:
V
|
is
head of
clause!
Comp:
PP
Head:
P
|
on
Obj:
NP
Det:
D
|
the
Head:
N
|
table
43
Clause without Main Verb –
Double R
SRE
Subj
|
ORE
Spec
|
D
|
the
Head
|
N
|
book
Spec
|
Aux
|
is
Head
|
Pred-Prep
Head
|
P
|
on
head of
clause!
the book is on the table
SRE  Subj Spec Head
Subj  ORE
Spec  Aux
Head  Pred-Prep
Pred-Prep  Head Obj
Grammatical
Construction
Obj
|
ORE
Spec
|
D
|
the
Head
|
N
|
table
44
Clause without Main Verb –
Simpler Syntax
the book’s on the table
S  NP AUX PP
S
NP
AUX
Syntactic Tier:
D
N
|
|
the book
TENSEpres
VAUX
|
be
PP
||
P
|
on
NP
D
|
the
GF Tier:
CS Tier:
N
|
table
Subject
BE(THEME:X, ON(THEME:Y))
45
Clause without Main Verb –
Cambridge Grammar
the book’s on the table
Clause
Subj:
NP
Det:
D
|
the
fused?
Head:
N
|
book
Predicator:
V
|
’s
Clause  Subj:NP Pred:VP
Pred:VP  Pred-or:V Comp:PP
Comp:PP  Head:P Obj:NP
Predicate:
VP
Comp:
PP
Head:
P
|
on
Don’t see how H&P can allow
GF’s to be fused
– inconsistent with grammatical evidence
Obj:
NP
Det:
D
|
the
Head:
N
|
table
46
Clause without Main Verb –
Double R
SRE
Subj
|
ORE
Spec
|
D
|
the
Head
|
N
|
book
Spec
|
Aux
|
’s
the book’s on the table
Head
|
Pred-Prep
Head
|
P
|
on
SRE  Subj+Spec Head
Subj  ORE
Spec  Aux
Head  Pred-Prep
Pred-Prep  Head Obj
Obj
|
ORE
Spec
|
D
|
the
Head
|
N
|
table
47
Passive Clause –
Simpler Syntax
S  NP AUX VPbe
VPbe  be (head) VP[PASS]
VP[PASS]  V[PASS] (PPby)
PPby  by NP
the book was taken by Joe
S
Syntactic Tier:
NP
VP
AUX
TENSEpast
the book
VP
bev-aux
[PASSIVE]
V
PP
[PASSIVE]
|
take
GF Tier:
CS:
Subject
byp
Object
NP
Joe
TAKE(AGENT:X, PATIENT:Y)
48
Passive Clause –
Cambridge Grammar
Clause
Subj:
NP
Det:
D
|
the
Clause  Subj:NP Pred:VP
Pred:VP  Pred-or:V Comp:Clausebare
Predicate: Comp:Clausebare  Pred:VP
Pred:VP  Pred-or:V Comp:PP
VP
Comp:
Clausebare
|
Predicate:
VP
Predicator:
V
Head:
|
N
was
|
book
Comp:
PP
Predicator:
V
|
taken
the book was taken by Joe
Comp:
P
Comp:
NP
|
by
Joe
49
Passive Clause –
Double R
SRE
Subj
|
ORE1
Spec
|
D
|
the
Head
|
N
|
book
Spec
|
Aux
|
was
Head
|
Pred-Trans-Verb
Head
|
V
|
taken
the book was taken by Joe
Obj
|
Bind1
SRE  Subj Spec Head
Subj  ORE1
Spec  Aux
Head  Pred-Trans-Verb
PTV  Head Obj Mod
Obj  Bind1
Mod
|
Pass-By-RE
Head, P
by
Grammatical
Construction
Obj
ORE
Head, PN
Joe
50
Yes-No-Question –
Double R
Y-N-Quest-SRE  Op Subj (Spec) Head
Pred-Trans-Verb  Head Obj
Did he take it?
Y-N-Quest-SRE
Operator
|
Aux
|
did
Subj
|
ORE
|
Head
|
Pron
|
he
Additional clause level GF:
1. Operator ~ Specifier
Grammatical
Construction
Head
|
Pred-Trans-Verb
Head
|
V
|
take
Obj
|
ORE
|
Head, Pron
|
it
51
Yes-No-Question –
Double R
Y-N-Quest-SRE  Op Subj (Spec) Head
Pred-Trans-Verb  Head Obj
Could he have taken it?
Y-N-Quest-SRE
Operator
|
Aux
|
could
Subj
|
ORE
|
Head
|
Pron
|
he
Spec
|
Aux
|
have
Head
|
Pred-Trans-Verb
Head
|
V
|
taken
Obj
|
ORE
|
Head, Pron
|
it
52
Wh-Question –
Double R
What did he take?
Wh-Quest-SRE  Wh-Focus Op Subj (Spec) Head
Pred-Trans-Verb  Head Obj
Wh-Quest-SRE
Wh-Focus
|
Wh-ORE1
|
Head
|
Wh-Pron
|
what
Operator
|
Aux
|
did
Subj
|
ORE1
|
Head
|
Pron
|
he
Grammatical
Construction
Head
|
Pred-Trans-Verb
Head
|
V
|
take
Obj
|
Bind1
Additional clause level GF:
1. Wh-Focus ~ Complement
53
Wh-Question –
Double R
What could he have
taken?
Wh-Quest-SRE  Wh-Focus Op Subj (Spec) Head
Pred-Trans-Verb  Head Obj
Wh-Quest-SRE
Wh-Focus
|
Wh-ORE1
Head
|
Wh-Pron
|
what
Operator
|
Aux
|
could
Subj
|
ORE
|
Head
|
Pron
|
he
Spec
|
Aux
|
have
Head
|
Pred-Trans-Verb
Head
|
V
|
taken
Obj
|
Bind1
54
Wh-Question + Passive + Ditrans –
Double R
What could he have
been given?
Wh-Quest-SRE  Wh-Focus Op Subj (Spec) Head
Pred-Ditrans-Verb  Head (IObjxor) Obj (Recipxor)
Wh-Quest-SRE
Grammatical
Construction
Wh-Focus Operator
Subj
Spec
Head
|
|
|
|
|
Wh-ORE1
Aux
ORE2
Aux
Pred-Ditrans-Verb
|
|
|
Head
could
Head
have been
|
|
Head
IObj
Obj
Wh-Proninan
Pronhuman
|
|
|
|
|
V
Bind2
Bind1
what
he
|
given
Animacy determines
binding!
55
Wh-Question + Passive + Ditrans –
Double R
Who could it have
been given?
Wh-Quest-SRE  Wh-Focus Op Subj (Spec) Head
Pred-Ditrans-Verb  Head (IObjxor) Obj (Recipxor)
Wh-Quest-SRE
Wh-Focus
|
Wh-ORE1
Head
|
Wh-Pronhuman
|
who
Operator
|
Aux
|
could
Animacy determines
binding!
Subj
Spec
Head
|
|
|
ORE2
Aux
Pred-Ditrans-Verb
|
Head
have been
|
Head
IObj
Obj
Proninan
|
|
|
|
V
Bind1
Bind2
it
|
given
56
Wh-Question + Passive + Ditrans –
Double R
Wh-Quest-SRE  Wh-Focus Op Subj (Spec) Head
Pred-Ditrans-Verb  Head (IObjxor) Obj (Recipxor)
Who could it
have been given to?
Wh-Quest-SRE
Wh-Focus
|
Wh-ORE1
Head
|
Wh-Pron
|
who
Operator
|
Aux
|
could
Subj
|
ORE2
|
Head
|
Pron
|
it
Spec
|
Aux
Head
|
Pred-Ditrans-Verb
have been
Head
|
V
|
given
Obj
|
Bind2
Recip
|
To-LRE
P
|
to
Obj
|
Bind1
57
Grammatical Features of Nominals
in English
• Definiteness – definite, indefinite, universal
• Number – singular, plural
• Animacy – human, animate, inanimate
• Gender – male, female
• Person – first, second, third
• Case – subj, obj, gen (2)
58
Why We Need Grammatical
Features
•
Definiteness:
– Give me the ball (definite)
– Give me a ball (indefinite)
•
or
Number
–
The men (plural) kick the ball (sing).
They
(plural)…
• Animacy
–
•
The man (human) kicks the ball
(inanimate).
It
(inanimate)…
Gender
–
The man (male) likes the woman (female).
She
(female)…
59
Simple Nominal
the man
definite
singular
human
male
“the” projects definite to obj-refer-expr
“man” projects singular, human and male
60
Grammatical Features of Clauses in
English
• Tense – present, past, non-finite
• Aspect – perfect, progressive
• Modality – “could”, “should”, “must”…
• Polarity – negative
• Voice – active, inactive, passive
61
Simple Clause
…could not have gone
present
finite
active
perfect
negative
“could”
“could not” recognized as a multi-word unit
“could” projects finite present tense and modality
“not” projects negative polarity
“have gone” projects perfect aspect and active voice
62
Summary
•
•
•
Representations matter!
Language is complex!
In complex systems, overall coherence is more
important than overall simplicity!
– Einstein: make your theory as simple as possible, but no
simpler!
– Computational implementation necessitates coherence
• If axioms + logical reasoning  incoherence or a
system that is obviously false, then question your
axioms or your “logical” reasoning
– E.g. if innateness assumptions lead to overly complex
representations, then question the innateness assumptions
or the reasoning
63
Theoretical Foundations
Language Representation and Processing
•
Double R Grammar
– Cognitive Linguistic theory of the grammatical
encoding of referential and relational meaning
•
Double R Process
– Psycholinguistic theory of the processing of
English text into Double R Grammar based
representations
•
Double R Model
– Computational implementation using the ACT-R
cognitive architecture and modeling environment
DoubleRTheory.com
64
Double R Process
• Serial, incremental, pseudo-deterministic language
processor with a non-monotonic context
accommodation mechanism (with limited
parallelism) that is capable of making modest
changes to the evolving representation
•
Parallel, interactive, highly context sensitive,
probabilistic mechanism which uses all available
information to make the best choice at each choice
point
•
Processor presents the appearance and efficiency of
deterministic processing, but is capable of handling
the ambiguity which makes truly deterministic
processing impossible
65
Double R Process
• Construction Driven Language Processing
– Activation, Selection and Integration of
constructions corresponding to the linguistic
input
•
Lexical items in the input activate constructions
– Activation depends on current input, current
context, and prior history of use
– “give” activates ditransitive verb construction
•
•
Most highly activated construction is selected
Selected construction is integrated with evolving
representation
66
Double R Process
• Adhere to well-established cognitive constraints on
Human Language Processing
•
Don’t use any obviously cognitively implausible
mechanisms!
•
Adhering to cognitive constraints may actually
facilitate the development of functional NLP systems
– Pushes development in directions that are more
likely to be successful given inherently human
nature of language processing
– You don’t know what you’re giving up when you
adopt cognitively implausible mechanisms!
67
ACT-R Cognitive Architecture
•
Theory of human cognition based on 40+ years of
psychological research (Anderson, 2007)
– Computational implementation since 1993
•
Combines a symbolic procedural memory
implemented as a production system with a
symbolic frame based declarative memory (DM)
•
Includes modules for vision, audition, and motor
processing
– Supports interaction with external world
http://act-r.psy.cmu.edu/
68
ACT-R Cognitive Architecture
•
Procedural memory is the central component
– All modules interface to procedural memory via
buffers (e.g. goal buffer, retrieval buffer, visual
buffer)
• Productions have “subsymbolic” utilities
– Productions match against buffers of other
modules
– Intentional module goal buffer is primary driver of
behavior
– Matching production with highest utility is
selected for execution
69
ACT-R Cognitive Architecture
•
DM contains chunks which are frame based
– Chunk type + slot-value pairs (aka AVMs)
•
Chunk types are organized into a single inheritance
hierarchy
•
Chunks have “subsymbolic” activations based on
current input, current context and prior history of
use
• Chunks are retrieved from memory by execution of a
production which specifies a retrieval template
– DM chunk with highest activation that matches
retrieval template is retrieved (soft constraint
retrieval)
70
ACT-R Cognitive Architecture
Intentional Module
Declarative Module
(not identified)
(Temporal/Hippocampus)
Retrieval Buffer
(DLPFC)
(VLPFC)
Productions
(Basal Ganglia)
Goal Buffer
modules &
buffers
mapped to
brain
regions
Matching (Striatum)
Selection (Pallidum)
Execution (Thalamus)
Visual Buffer
Manual Buffer
(Parietal)
(Motor)
Visual Module
Manual Module
(Occipital/etc)
(Motor/Cerebellum)
External World
71
ACT-R Cognitive Architecture
•
Supports timing of cognitive processing
– Production execution takes 50 ms
– DM chunk retrieval time depends on level of
activation of retrieved chunk
– Timing of motor events based on Fitts’ Law
– Used for empirical validation of models
•
Provides a powerful debugging environment
72
Architectural Constraints
•
No language specific module
– although buffers and productions accessing buffers might
be viewed as a module
• Forward chaining productions with no backtracking
• Limited pattern matching – not full unification
• Serial bottleneck
– only one production can execute at a time
• Modules interact with production system via buffers
– buffers have limited capacity for storing current context
• Activation spreads in parallel
• Activation and Utility subject to noise
73
Constraints on Human Language
Processing
•
Visual World Paradigm (Tanenhaus et al. 1995)
– Subjects presented with a visual scene
– Subjects listen to auditory linguistic input describing scene
•
Immediate determination of meaning
– Subjects look immediately at referents of linguistic
expressions, sometimes before end of expression
•
Incremental processing
“the green…”
•
Interactive processing (Trueswell et al. 1999)
– Ambiguous expressions are processed consistent with scene
“put the arrow on the paper into the box”
74
Constraints on Human Language
Processing
•
According to Crocker (1999), there are three basic
mechanisms for dealing with ambiguity in natural language
– Serial processing with backtracking or reanalysis
– Deterministic processing with lookahead (Marcus 1980)
– Parallel processing with alternative analyses carried forward
in parallel (Gibson 1991; MacDonald, Pearlmutter &
Seidenberg 1994; Trueswell & Tanenhaus 1994)
•
According to Lewis (2000) “…existing evidence is
compatible only with probabilistic serial-reanalysis models, or
ranked parallel models augmented with a reanalysis
component.”
•
According to Gibson & Pearlmutter (2000)
“noncompetitive ranked parallel models” are most consistent
with the empirical evidence
75
Constraints on Human Language
Processing
•
Serial and deterministic with reanalysis for
pathological input
– Empirical evidence that we don’t carry forward all
representations in parallel – Garden Path Sentences
• “The horse raced past the barn fell” (Bever 1970)
• “The old train the young” (Just & Carpenter, 1987)
– Empirical evidence that we don’t retract previously built
representations (Christianson et al. 2001)
• “While Mary dressed the baby sat up on the bed”
– In a post test, a majority of subjects answered yes to
the question “Did Mary dress the baby?”
– Processing doesn’t slow down with increasing length of
non-pathological input
– Typically only aware of a single interpretation
76
Constraints on Human Language
Processing
•
Parallel and probabilistic with reanalysis for
pathological input
– Empirical evidence that we may carry forward multiple
representations in parallel – Garden Path Effects can be
eliminated with sufficient context
– Empirical evidence that dispreferred representations can
affect processing time (Gibson & Pearlmutter 2000)
•
It’s extremely difficult to empirically falsify either
– Could be parallel slow down or occasional switch between
serial alternatives that causes effect
•
Don’t have all the answers, but maybe it’s both!
– A parallel, probabilistic substrate may make a pseudodeterministic serial processing mechanism possible!
77
Cognitively Implausible Mechanism
•
Serial processing with algorithmic backtracking
– Algorithmically simple, but…
• Computationally intractable for NLP which is highly
ambiguous
• Context which led to dead end is retracted on backtracking
– Why give up the context?
– How do we know it’s a dead end?
•
Practical Consequences
– No hope for on-line processing in real-time in large coverage
NLP system
– No hope for integration with speech recognition system
– Performance degrades with length of input
– Can’t easily handle degraded or ungrammatical input
78
Cognitively Implausible Mechanism
•
Multiple pass or multi-stage parsing
– Separate passes tokenize and assign part of speech
• Can’t use full context in each pass
• Errors get propagated
– Separate pass builds structure
• Typically limited to using part of speech of words
– Separate pass determines meaning
• Practical Consequences
–
–
–
–
Difficult to do on-line processing in real-time
Can’t easily integrate with speech recognition
Performance degrades with length of input
Limited context available to handle ambiguity at each stage
79
Outrageously Implausible
Mechanism!
•
Parsing input from right to left (Microsoft NLP system)
– May have engineering advantages, but…
• Presumes a staged approach to NLP
• Completely ignores cognitive plausibility
•
Practical consequences
• Impossible to do on-line processing in real-time
– Must wait for end of input
• Nearly impossible to integrate with speech recognition
80
Cognitively Plausible Mechanism?
•
Deterministic processing with lookahead
– Many ambiguities resolved by looking ahead a few words,
but…
• Don’t know how far to look ahead
– Cognitive plausibility improved by limiting amount of
lookahead
• 3 constituent lookahead (Marcus 1980)
• 1 word lookahead (Henderson 2004)
•
Practical consequences
– Difficult to use with eager algorithms for which there is good
empirical evidence (immediate determination of meaning)
– The smaller the lookahead, the less deterministic
81
Cognitively Plausible Mechanism?
•
Parallel processing with multiple analyses carried
forward
– “Full parallelism – where every analysis is pursued – is not
psychologically possible” (Crocker 1999)
– Cognitive plausibility improved by limiting number of
analyses carried forward and ranking alternatives (bounded
ranked parallelism) and not having analyses compete
•
Practical Consequences
– The longer and more ambiguous the input, the less likely to
have the correct representation in the parallel spotlight –
necessitating a reanalysis mechanism
– Impractical if multiple representations must be built at each
choice point as opposed to just being selected
82
Cognitively Plausible Mechanism
•
Pseudo-deterministic, serial processing mechanism
with context accommodation operating over a parallel,
probabilistic substrate
– Parallel, probabilistic substrate proposes best alternative
given current context
– Processor proceeds as though it were serial and
deterministic, but accommodates the subsequent input as
needed
– Integrates the advantages of parallel processing with an
essentially serial processing mechanism
•
Practical Consequences
– How to accommodate when things go seriously wrong?
– Mechanism is essentially non-monotonic
83
Cognitively Plausible Mechanism
•
Serial, Pseudo-deterministic processing and Context
Accommodation
– Uses ACT-R’s production system
– Builds structure
– Limited parallelism
•
Parallel, Probabilistic processing
– Uses ACT-R’s declarative memory
– Retrieves existing structure from memory
84
Context Accommodation
• If current input is unexpected given the prior
context, then accommodate the input
– Adjust the representation
– Coerce the input into the representation
•
The following example demonstrates the context
accommodation mechanism
– “no target airspeed or altitude restrictions”
85
“no”  object referring expression
no
“no” projects obj-refer-expr and functions as specifier
“head-indx” indicates head expected
“bind-indx” provides index for binding
86
“target”  head
no target
integration
tree structures generated automatically with dynamic visualization
tool (Heiberg, Harris & Ball 2007) based on phpSyntaxTree
software (Eisenberg & Eisenberg)
87
“airspeed”  head
no target airspeed
override
function shift
integration
Accommodation
of second noun via
function shift and overriding
88
“or altitude”  conj
no target airspeed or altitude
integration
Conjunction integrated into
noun
89
“restrictions”  head
no target airspeed or altitude restrictions
override
function shift
Accommodation
of new head via
function shift and override
integration
Appearance of parallel processing!
90
Types of Accommodation
• Coercion
– “the hiking of Mt Lemon” – head of nominal
• “hiking” construed objectively, arguments not expressed
(“of Mt Lemon” functions as a modifier)
– “a Bin Laden supporter”
• Proper Noun functions as modifier
– “you’re no Jack Kennedy”
• Proper Noun functions as head (following specifier)
– “the newspaper boy porched the newspaper” – nonce
expression (H. Clark 1983)
• “porched” construed as transitive action
91
Types of Accommodation
•
Override
– Single word vs. Multi-Word Expression (MWE)
• “kicked…”  transitive verb
– “kicked the bucket”  idiomatic expression
• “take…”  transitive verb
– “take a hike” “take five” “take time” “take place”
“take out” “take my wife, please” “take a long walk off
a short pier” …  many idiomatic expressions
• Not possible to carry all forward in parallel
– Morphologically simple vs. complex
• “car…”  noun (sing)
– “carpet…”  noun (sing)
– “carpets”  noun (plur)
– “carpeting”  noun (sing) or verb
92
Types of Accommodation
• Grammatical Function Shift
– “he gave it to me”
• direct object (initial preference due to inanimacy)
– “he gave it the ball”
• direct object (initial preference)  indirect object
– “he gave her the ball”
• indirect object (initial preference due to animacy)
– “he gave her to the groom”
• indirect object (initial preference)  direct object
93
Types of Accommodation
• Nominal Head Override
• “he gave her the dog biscuit”  head = her
• “he gave her dog the biscuit”  head = dog
•
Grammatical Function “Juggling”
–
–
–
–
–
–
“he gave the…”  indirect object
“he gave the very old bone…”  direct object
“he gave the very old bone collector…”  indirect object
“he gave the very old dog…”  indirect object
“he gave the very old dog collar…”  direct object
“he gave the very old dog to me”  direct object
94
Types of Accommodation
• Grammatical Function Shift
– “he said that…”
• In context of “said”, “that” typically functions as a
complementizer
– But subsequent context can cause a function shift from
• complementizer
– “he said that she was happy”
• To nominal specifier to
– “he said that book was funny”
• To nominal head
– “he said that.”
95
Types of Accommodation
• Grammatical Function Shift
– “pressure” vs.
“pressure valve” vs.
“pressure valve adjustment” vs.
“pressure valve adjustment screw” vs.
“pressure valve adjustment screw fastener” vs.
“pressure valve adjustment screw fastener part” vs.
“pressure valve adjustment screw fastener part number”
• Serial nouns (and verbs) incrementally shift from head to
modifier function as each new head is processed
• Functions like lookahead, but isn’t limited
• Not clear if a bounded ranked parallel mechanism can
handle this!
– 2n possibilities if head or modifier at each word
96
Types of Accommodation
• Modulated Projection
– “the rice” vs. “rice”
– “the” projects a nominal and functions as a specifier
– In the context of “the” “rice” is integrated as the head of the
nominal
– When there is no specifier, “rice” projects a nominal and
functions as the head without separate specification
nominal
spec
nominal
vs.
head
rice
the
“the rice”
head
rice
“rice”
97
Grammatical Feature
Accommodation
•
Grammatical features may be redundantly encoded
and may conflict without the expression being
ungrammatical
– aindef+sing fewindef+plur booksindef+plur
– thedef booksindef+plur
– someindef+plur booksing
– aindef+sing Ronald Reagandef+sing republicansing
– he haspres+act givenpass+perf me the ball
– he ispres+inact givenpass+perf the ball
– he haspres+act beenpass+perf givenpass+perf it
98
Summary of
Context Accommodation
• Context Accommodation is part and parcel of the
pseudo-deterministic processing mechanism
– Not viewed as a repair mechanism (Lewis 1998)
•
Processor proceeds as though it were deterministic, but
accommodates the input as needed
•
Gives the appearance of parallel processing in a serial,
deterministic mechanism
99
Combining Serial, Deterministic
and Parallel, Probabilistic Mechanisms
Parallel Probabilistic
PDP
Probabilistic
LTAG
The parallel probabilistic substrate makes
a pseudo-deterministic serial processing
mechanism possible!
Parallel Distributed Processing
Supertag
Stapling
Tree Supertagging
Double R
Construction Activation
& Selection
Construction
Integration
Lexicalized
PCFG
Lexical Rule Selection
Rule Application
PCFG
CFG
Rule
Selection
Pseudo
Deterministic
Range
Rule Application
Rule Selection & Application
Nondeterministic
Serial Deterministic
100
Questions?
101