PPT - International Computer Science Institute

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Simulation-based language
understanding
“Harry walked to the cafe.”
Utterance
Constructions
Analysis Process
General
Knowledge
Belief State
Schema
walk
Trajector
Harry
Cafe
Goal
cafe
Simulation
Specification
Simulation
Simulation specification
The analysis process produces a simulation specification that
•includes image-schematic, motor control and conceptual structures
•provides parameters for a mental simulation
NTL Manifesto
• Basic Concepts are Grounded in Experience
– Sensory, Motor, Emotional, Social,
• Abstract and Technical Concepts map by
Metaphor to more Basic Concepts
• Neural Computation models all levels
Simulation based Language
Understanding
Utterance
Discourse & Situational
Context
Constructions
Analyzer:
incremental,
competition-based,
psycholinguistically
plausible
Semantic Specification:
image schemas, frames,
action schemas
Simulation
Embodied Construction Grammar
• Embodied representations
– active perceptual and motor schemas
(image schemas, x-schemas, frames, etc.)
– situational and discourse context
• Construction Grammar
– Linguistic units relate form and
meaning/function.
– Both constituency and (lexical) dependencies
allowed.
• Constraint-based
– based on feature unification (as in LFG, HPSG)
– Diverse factors can flexibly interact.
Embodied Construction Grammar
ECG
(Formalizing Cognitive Linguisitcs)
1. Linguistic Analysis
2. Computational Implementation
a. Test Grammars
b. Applied Projects – Question Answering
3. Map to Connectionist Models, Brain
4. Models of Grammar Acquisition
ECG Structures
• Schemas
– image schemas, force-dynamic schemas, executing
schemas, frames…
• Constructions
– lexical, grammatical, morphological, gestural…
• Maps
– metaphor, metonymy, mental space maps…
• Situations (Mental Spaces)
– discourse, hypothetical, counterfactual…
Embodied schemas
schema name
schema Source-Path-Goal
roles
source
path
goal
trajector
role name
schema Container
roles
interior
exterior
portal
boundary
Boundary
Source
Trajector
Interior
Portal
Goal
Path
Exterior
These are abstractions over sensorimotor experiences.
ECG Schemas
schema <name>
subcase of <schema>
evokes <schema> as
<local name>
roles < local role >:
<role restriction>
constraints
<role> ↔ <role>
<role>  <value>
<predicate>
schema Hypotenuse
subcase of LineSegment
evokes Right-Tri as rt
roles
{lower-left: Point}
{upper-right: Point}
constraints
self ↔ rt.long-side
Source-Path-Goal; Container
schema SPG
subcase of TrajLandmark
roles
source: Place
path: Directed–Curve
goal: Place
{trajector: Entity}
{landmark: BoundedRegion}
schema Container
roles
interior: Bounded-Region
boundary: Curve
portal: Bounded-Region
Referent Descriptor Schemas
schema RD
roles
category
gender
count
specificty
resolved Ref
modifications
schema RD5 // Eve
roles
HumanSchema
Female
one
Known
Eve Sweetser
none
ECG Constructions
construction <name>
subcase of <construction>
constituents
<name>:<construction>
form
constraints
<name> before/meets
<name>
meaning:
constraints
// same as for schemas
construction SpatialPP
constituents
prep: SpatialPreposition
lm: NP
form
constraints
prep meets lm
meaning:
TrajectorLandmark
constraints
selfm ↔ prep
landmark ↔ lm.category
Into and The CXNs
construction Into
subcase of
SpatialPreposition
form: WordForm
constraints
orth  "into"
meaning: SPG
evokes Container as c
constraints
landmark ↔ c
goal ↔ c.interior
construction The
subcase of Determiner
form:WordForm
constraints
orth  "the"
meaning
evokes RD as rd
constraints
rd.specificity  “known”
Two Grammatical CXNs
construction DetNoun
subcase of NP
constituents
d:Determiner
n:Noun
form constraints
d before n
meaning constraints
selfm ↔ d.rd
category ↔ n
construction NPVP
subcase of S
constituents
subj: NP
vp: VP
form constraints
subj before vp
meaning constraints
profiled-participant ↔
subj
Simulation specification
The analysis process produces a simulation specification that
•includes image-schematic, motor control and conceptual structures
•provides parameters for a mental simulation
Competition-based analyzer
• An analysis is made up of:
– A constructional tree
– A semantic specification
– A set of resolutions
Johno Bryant
A-GIVE-B-X
subj
v
obj2
obj1
Ref-Exp
Give
Ref-Exp
Ref-Exp
Bill
gave
Mary
the book
@Man
Give-Action
Bill
giver
@Woman
Mary
recipient
theme
@Book
book01
Combined score determines best-fit
• Syntactic Fit:
– Constituency relations
– Combine with preferences on non-local elements
– Conditioned on syntactic context
• Antecedent Fit:
– Ability to find referents in the context
– Conditioned on syntax match, feature agreement
• Semantic Fit:
– Semantic bindings for frame roles
– Frame roles’ fillers are scored
0Eve1walked2into3the4house5
Constructs
-------------NPVP[0] (0,5)
Eve[3] (0,1)
ActiveSelfMotionPath
[2] (1,5)
WalkedVerb[57] (1,2)
SpatialPP[56] (2,5)
Into[174] (2,3)
DetNoun[173] (3,5)
The[204] (3,4)
House[205] (4,5)
Schema Instances
------------------SelfMotionPathEvent
[1]
HouseSchema[66]
WalkAction[60]
Person[4]
SPG[58]
RD[177] ~ house
RD[5]~ Eve
Unification chains and their fillers
SelfMotionPathEvent[1].mover
SPG[58].trajector
WalkAction[60].walker
RD[5].resolved-ref
RD[5].category
Filler: Person4
SelfMotionPathEvent[1]
.landmark
House[205].m
RD[177].category
SPG[58].landmark
Filler:HouseSchema66
SpatialPP[56].m
Into[174].m
SelfMotionPathEvent[1].spg
Filler: SPG58
WalkedVerb[57].m
WalkAction[60].routine
WalkAction[60].gait
SelfMotionPathEvent[1]
.motion
Filler:WalkAction60
Summary: ECG
• Linguistic constructions are tied to a model of
simulated action and perception
• Embedded in a theory of language processing
– Constrains theory to be usable
– Basis for models of grammar learning
• Precise, computationally usable formalism
– Practical computational applications, like MT and NLU
– Testing of functionality, e.g. language learning
• A shared theory and formalism for different
cognitive mechanisms
– Constructions, metaphor, mental spaces, etc.
• Reduction to Connectionist and Neural levels
Productive Argument Omission (Mandarin)
Johno Bryant & Eva Mok
1
ma1+ma gei3 ni3 zhei4+ge
• Mother (I) give you this (a toy).
mother give 2PS this+CLS
2
ni3 gei3
• You give auntie [the peach].
yi2
2PS give auntie
3
ao
ni3 gei3
EMP 2PS give
4
gei3
ya
EMP
• Oh (go on)! You give [auntie]
[that].
• [I] give [you] [some peach].
give
CHILDES Beijing Corpus (Tardiff, 1993; Tardiff, 1996)
Arguments are omitted with different
probabilities
% elided (98 total utterances)
100.00%
90.00%
80.00%
Giver
Theme
70.00%
60.00%
50.00%
Recipient
40.00%
30.00%
20.00%
10.00%
0.00%
All args omitted: 30.6%
No args omitted: 6.1%
Analyzing ni3 gei3 yi2 (You give
auntie)
Two of the competing analyses:
ni3
gei3
yi2
omitted
↓
↓
↓
↓
Giver Transfer Recipient Theme
ni3
gei3
omitted
yi2
↓
↓
↓
↓
Giver Transfer Recipient Theme
• Syntactic Fit:
– P(Theme omitted | ditransitive cxn) = 0.65
– P(Recipient omitted | ditransitive cxn) = 0.42
(1-0.78)*(1-0.42)*0.65 = 0.08
(1-0.78)*(1-0.65)*0.42 = 0.03
Using frame and lexical information to
restrict type of reference
The Transfer Frame
Giver
Lexical Unit gei3
Recipient
Giver
(DNI)
Theme
Recipient
(DNI)
Theme
(DNI)
Manner
Purpose
Means
Reason
Place
Time
Can the omitted argument be recovered
from context?
• Antecedent Fit:
ni3
gei3
yi2
omitted
↓
↓
↓
↓
Giver Transfer Recipient Theme
ni3
gei3
omitted
yi2
↓
↓
↓
↓
Giver Transfer Recipient Theme
Discourse & Situational
Context
child
peach
table
mother
auntie
?
How good of a theme is a peach?
How about an aunt?

Semantic Fit:
ni3
gei3
yi2
omitted
↓
↓
↓
↓
Giver Transfer Recipient Theme
ni3
gei3
omitted
yi2
↓
↓
↓
↓
Giver Transfer Recipient Theme
The Transfer Frame
Giver
(usually animate)
Recipient
(usually animate)
Theme
(usually inanimate)
The argument omission patterns shown
earlier
can be covered with just ONE construction
% elided (98 total utterances)
90.00%
80.00%
Giver
Theme
70.00%
60.00%
50.00%
Recipient
40.00%
30.00%
20.00%
10.00%
Subj
Verb
Obj1
Obj2
↓
↓
↓
↓
Giver
P(omitted|cxn):
0.78
Transfer Recipient
0.42
0.00%
Theme
0.65
• Each construction is annotated with probabilities of omission
• Language-specific default probability can be set
Leverage process to simplify
representation
• The processing model is complementary
to the theory of grammar
• By using a competition-based analysis
process, we can:
– Find the best-fit analysis with respect to
constituency structure, context, and semantics
– Eliminate the need to enumerate allowable
patterns of argument omission in grammar
• This is currently being applied in models of
language understanding and grammar
Modeling context for
language understanding and learning
• Linguistic structure reflects experiential structure
– Discourse participants and entities
– Embodied schemas:
• action, perception, emotion, attention, perspective
– Semantic and pragmatic relations:
• spatial, social, ontological, causal
• ‘Contextual bootstrapping’ for grammar learning
The context model tracks accessible
entities, events, and utterances
Discourse &
Situational
Context
Discourse:
Discourse01
participants: Eve , Mother
objects: Hands, ...
discourse-history: DS01
situational-history: Wash-Action
Each of the items in the context
model has rich internal structure
Discourse:
Participants:
Eve
category: child
gender: female
name: Eve
age: 2
Objects:
Mother
category: parent
gender: female
name: Eve
age: 33
Situational History:
Wash-Action
washer: Eve
washee: Hands
Hands
category: BodyPart
part-of: Eve
number: plural
accessibility: accessible
Discourse History:
DS01
speaker: Mother
addressee: Eve
attentional-focus: Hands
content: {"are they clean yet?"}
speech-act: question
Analysis produces a semantic
specification
Utterance
“You washed
them”
Discourse &
Situational
Context
World
Knowledge
Analysis
Semantic Specification
WASH-ACTION
washer: Eve
washee: Hands
Linguistic
Knowledge
How Can Children Be So Good At
Learning Language?
• Gold’s Theorem:
No superfinite class of language is identifiable in the
limit from positive data only
• Principles & Parameters
Babies are born as blank slates but acquire language
quickly (with noisy input and little correction) →
Language must be innate:
Universal Grammar + parameter setting
But babies aren’t born as blank slates!
And they do not learn language in a vacuum!
Key ideas for a NT of language acquisition
Nancy Chang and Eva Mok
• Embodied Construction Grammar
• Opulence of the Substrate
– Prelinguistic children already have rich sensorimotor
representations and sophisticated social knowledge
• Basic Scenes
– Simple clause constructions are associated directly with
scenes basic to human experience
(Goldberg 1995, Slobin 1985)
• Verb Island Hypothesis
– Children learn their earliest constructions
(arguments, syntactic marking) on a verb-specific basis
(Verb Island Hypothesis, Tomasello 1992)
Embodiment and Grammar Learning
Paradigm problem for Nature vs. Nurture
The poverty of the stimulus
The opulence of the substrate
Intricate interplay of genetic and environmental,
including social, factors.
Two perspectives on grammar learning
Computational models
Developmental
evidence
• Grammatical induction
– language identification
– context-free grammars,
unification grammars
– statistical NLP (parsing,
etc.)
• Word learning models
– semantic representations
• logical forms
• discrete representations
• continuous
representations
– statistical models
• Prior knowledge
–
–
–
–
primitive concepts
event-based knowledge
social cognition
lexical items
• Data-driven learning
– basic scenes
– lexically specific patterns
– usage-based learning
Key assumptions for language
acquisition
• Significant prior conceptual/embodied
knowledge
– rich sensorimotor/social substrate
• Incremental learning based on experience
– Lexically specific constructions are learned
first.
• Language learning tied to language use
– Acquisition interacts with comprehension,
production;
reflects communication and experience in world.
– Statistical properties of data affect learning
Analysis draws on constructions
and context
Form
Meaning
you
Context
Addressee
Eve
addressee
before
washed
before
them
washer
washer
Wash-Action
Wash-Action
washee
washee
ContextElement
Hands
Discourse
Segment
attentionalfocus
Learning updates linguistic knowledge
based on input utterances
Utterance
Discourse &
Situational
Context
Analysis
Partial
SemSpec
World
Knowledge
Linguistic
Knowledge
Learning
Context aids understanding:
Incomplete grammars yield partial SemSpec
Form
you
Meaning
Addressee
Context
Eve
addressee
washer
washed
Wash-Action
Wash-Action
Discourse
Segment
washee
them
ContextElement
Hands
attentionalfocus
Context bootstraps learning:
new construction maps form to meaning
Form
Meaning
you
Context
Addressee
Eve
addressee
before
washed
before
them
washer
washer
Wash-Action
Wash-Action
washee
washee
ContextElement
Hands
Discourse
Segment
attentionalfocus
Context bootstraps learning:
new construction maps form to meaning
Form
Meaning
you
Addressee
YOU-WASHED-THEM
constituents:
YOU, WASHED, THEM
before
washed
before
washer
Wash-Action
washee
form:
YOU before WASHED
WASHED before THEM
meaning: WASH-ACTION
washer: addressee
washee: ContextElement
them
ContextElement
Grammar learning: suggesting new CxNs
and reorganizing existing ones
Utterance
World
Knowledge
Discourse &
Situational
Context
reorganize
Linguistic
Knowledge
•
•
•
merge
join
split
reinforcement
Analysis
hypothesize
•
Partial
SemSpec
•
map form to
meaning
learn contextual
constraints
Challenge: How far up to
generalize
Inanimate Object
• Eat rice
• Eat apple
• Eat watermelon
• Want rice
• Want apple
• Want chair
Manipulable
Objects
Unmovable
Objects
Food
Furniture
Fruit
apple
Savory
watermelon
Chair
rice
Sofa
Challenge: Omissible
constituents
• In Mandarin, almost anything available in
context can be omitted – and often is in
child-directed speech.
• Intuition:
• Same context, two expressions that differ
by one constituent  a general
construction with the constituent being
omissible
• May require verbatim memory traces of
utterances + “relevant” context
When does the learning stop?
Bayesian Learning Framework
Gˆ  argmax P(G | U , Z )
G
 argmax P(U | G, Z ) P(G )
G
Schemas +
Constructions
reorganize
reinforcement
Analysis +
Resolution
Context
Fitting
hypothesize
SemSpec
• Most likely grammar given utterances and
context
• The grammar prior includes a preference for the
“kind” of grammar
• In practice, take the log and minimize cost 
Minimum Description Length (MDL)
Intuition for MDL
• S -> Give me NP
• NP -> the book
• NP -> a book
•
•
•
•
S -> Give me NP
NP -> DET book
DET -> the
DET -> a
Suppose that the prior is inversely proportional to the size
of the grammar (e.g. number of rules)
It’s not worthwhile to make this generalization
51
Intuition for MDL
•
•
•
•
•
•
•
•
•
S -> Give me NP
NP -> the book
NP -> a book
NP -> the pen
NP -> a pen
NP -> the pencil
NP -> a pencil
NP -> the marker
NP -> a marker
•
•
•
•
•
•
•
•
S -> Give me NP
NP -> DET N
DET -> the
DET -> a
N -> book
N -> pen
N -> pencil
N -> marker
Usage-based learning:
comprehension and production
discourse & situational
context
world knowledge
utterance
comm. intent
constructicon
analyze
&
resolve
reinforcement
(usage)
hypothesize
constructions
& reorganize
analysis
simulation
reinforcement
(usage)
reinforcement
(correction)
generate
utterance
reinformcent
(correction)
response
From Molecule to Metaphor
www.m2mbook.org
I. Embodied Information Processing
II. How the Brain Computes
III. How the Mind Computes
IV. Learning Concrete Words
V. Learning Words for Actions
VI. Abstract and Metaphorical Words
VII. Understanding Stories
VIII. Combining Form and Meaning
IX. Embodied Language
Basic Questions Addressed
• How could our brain, a mass of chemical cells,
produce language and thought?
• How much can we know about our own experience?
• How do we learn new concepts?
• Does our language determine how we think?
• Is language innate?
• How do children learn grammar?
• Why make computational brain models of thought?
• Will our robots understand us?
Language, Learning and Neural Modeling
www.icsi.berkeley.edu/AI
• Scientific Goal
Understand how people learn and use language
• Practical Goal
Deploy systems that analyze and produce language
• Approach
Build models that perform cognitive tasks, respecting
all experimental and experiential constraints
Embodied linguistic theories with advanced
biologically-based computational methods
Simulation Semantics
• BASIC ASSUMPTION: SAME REPRESENTATION FOR
PLANNING AND SIMULATIVE INFERENCE
– Evidence for common mechanisms for recognition and
action (mirror neurons) in the F5 area (Rizzolatti et al (1996),
Gallese 96, Boccino 2002) and from motor imagery
(Jeannerod 1996)
• IMPLEMENTATION:
– x-schemas affect each other by enabling, disabling or
modifying execution trajectories. Whenever the
CONTROLLER schema makes a transition it may set, get,
or modify state leading to triggering or modification of other
x-schemas. State is completely distributed (a graph marking)
over the network.
• RESULT: INTERPRETATION IS IMAGINATIVE SIMULATION!
Grammar learning: hypothesizing new
constructions and reorganizing them
Utterance
World
Knowledge
Discourse &
Situational
Context
reorganize
Linguistic
Knowledge
•
•
•
merge
join
split
reinforcement
Analysis
hypothesize
•
Partial
SemSpec
•
map form to
meaning
learn contextual
constraints
Discovering the Conceptual Primitives
2008 Cognitive Science Conference
Cognitive Science is now in a position to
discover the neural basis for many of the conceptual
primitives underlying language and thought. The
main concern is conceptual mechanisms that have
neural realization that does not depend on language
and culture. These concepts (the primitives) are
good candidates for a catalog of potential
foundations of meaning.
Lisa Aziz-Zadeh, USC - Neuroscience
Daniel Casasanto, Stanford – Psycholinguistics
Jerome Feldman, UCB/ICSI - AI
Rebecca Saxe, MIT - Development
Len Talmy, Buffalo,UCB – Cognitive Linguistics
Understanding an utterance in context:
analysis and simulation
Utterance
Discourse &
Situational
Context
World
Knowledge
Linguistic
Knowledge
Analysis
Semantic Specification
Simulation
Neural Theory of Language (Feldman, 2006)
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