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Simulation-based language understanding “Harry walked to the cafe.” SchemaTrajectorGoal walkHarrycafe Analysis Process Simulation Specification Utterance.

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Presentation on theme: "Simulation-based language understanding “Harry walked to the cafe.” SchemaTrajectorGoal walkHarrycafe Analysis Process Simulation Specification Utterance."— Presentation transcript:

1 Simulation-based language understanding “Harry walked to the cafe.” SchemaTrajectorGoal walkHarrycafe Analysis Process Simulation Specification Utterance Simulation Cafe Constructions General Knowledge Belief State

2 Simulation specification The analysis process produces a simulation specification that includes image-schematic, motor control and conceptual structures provides parameters for a mental simulation

3 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

4 Simulation based Language Understanding Constructions Simulation Utterance Discourse & Situational Context Semantic Specification: image schemas, frames, action schemas Analyzer: incremental, competition-based, psycholinguistically plausible

5 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.

6 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

7 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…

8 schema Container roles interior exterior portal boundary Embodied schemas Interior Exterior Boundary Portal Source Path Goal Trajector These are abstractions over sensorimotor experiences. schema Source-Path-Goal roles source path goal trajector schema name role name

9 ECG Schemas schema subcase of evokes as roles : constraints ↔  schema Hypotenuse subcase of Line- Segment evokes Right-Tri as rt roles {lower-left: Point} {upper-right: Point} constraints self ↔ rt.long-side

10 Source-Path-Goal; Container schema SPG subcase of TrajLandmark roles source: Place path: Directed–Curve goal: Place {trajector: Entity} {landmark: Bounded- Region} schema Container roles interior: Bounded-Region boundary: Curve portal: Bounded-Region

11 Referent Descriptor Schemas schema RD roles category gender count specificty resolved Ref modifications schema RD5 // Eve roles HumanSchema Female one Known Eve Sweetser none

12 ECG Constructions construction subcase of constituents : form constraints before/meets meaning: constraints // same as for schemas construction SpatialPP constituents prep: SpatialPreposition lm: NP form constraints prep meets lm meaning: TrajectorLandmark constraints self m ↔ prep landmark ↔ lm.category

13 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”

14 Two Grammatical CXNs construction DetNoun subcase of NP constituents d:Determiner n:Noun form constraints d before n meaning constraints self m ↔ d.rd category ↔ n construction NPVP subcase of S constituents subj: NP vp: VP form constraints subj before vp meaning constraints profiled-participant ↔ subj

15 Simulation specification The analysis process produces a simulation specification that includes image-schematic, motor control and conceptual structures provides parameters for a mental simulation

16 Competition-based analyzer An analysis is made up of: –A constructional tree –A semantic specification –A set of resolutions Bill gaveMarythe book MaryBill Ref-Exp Give A-GIVE-B-X subj vobj1 obj2 book01@Man@WomanGive-Action @Book giver recipient theme Johno Bryant

17 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

18 0 Eve 1 walked 2 into 3 the 4 house 5 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

19 Unification chains and their fillers SelfMotionPathEvent[1].mover SPG[58].trajector WalkAction[60].walker RD[5].resolved-ref RD[5].category Filler: Person4 SpatialPP[56].m Into[174].m SelfMotionPathEvent[1].spg Filler: SPG58 SelfMotionPathEvent[1].landmark House[205].m RD[177].category SPG[58].landmark Filler:HouseSchema66 WalkedVerb[57].m WalkAction[60].routine WalkAction[60].gait SelfMotionPathEvent[1].motion Filler:WalkAction60

20 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

21 Mother (I) give you this (a toy). CHILDES Beijing Corpus (Tardiff, 1993; Tardiff, 1996) ma1+magei3ni3zhei4+ge mothergive2PSthis+CLS You give auntie [the peach]. Oh (go on)! You give [auntie] [that]. Productive Argument Omission (Mandarin) Johno Bryant & Eva Mok 1 2 3 ni3gei3yi2 2PSgiveauntie aoni3gei3ya EMP 2PSgive EMP 4 gei3 give [I] give [you] [some peach].

22 Arguments are omitted with different probabilities All args omitted: 30.6% No args omitted: 6.1%

23 Analyzing ni3 gei3 yi2 (You give auntie) Syntactic Fit: –P(Theme omitted | ditransitive cxn) = 0.65 –P(Recipient omitted | ditransitive cxn) = 0.42 Two of the competing analyses: ni3gei3yi2omitted ↓↓↓↓ GiverTransferRecipientTheme ni3gei3omittedyi2 ↓↓↓↓ GiverTransferRecipientTheme (1-0.78)*(1-0.42)*0.65 = 0.08(1-0.78)*(1-0.65)*0.42 = 0.03

24 Using frame and lexical information to restrict type of reference Lexical Unit gei3 Giver (DNI) Recipient (DNI) Theme (DNI) The Transfer Frame Giver Recipient Theme Manner Means Place Purpose Reason Time

25 Can the omitted argument be recovered from context? Antecedent Fit: ni3gei3yi2omitted ↓↓↓↓ GiverTransferRecipientTheme ni3gei3omittedyi2 ↓↓↓↓ GiverTransferRecipientTheme Discourse & Situational Context childmother peachauntie table ?

26 How good of a theme is a peach? How about an aunt? The Transfer Frame Giver (usually animate) Recipient (usually animate) Theme (usually inanimate) ni3gei3yi2omitted ↓↓↓↓ GiverTransferRecipientTheme ni3gei3omittedyi2 ↓↓↓↓ GiverTransferRecipientTheme Semantic Fit: ni3gei3yi2omitted ↓↓↓↓ GiverTransferRecipientTheme

27 The argument omission patterns shown earlier can be covered with just ONE construction Each construction is annotated with probabilities of omission Language-specific default probability can be set SubjVerbObj1Obj2 ↓↓↓↓ GiverTransferRecipientTheme 0.780.420.65 P(omitted|cxn):

28 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 learning.

29 Best-fit example with theme omitted SubjVerbObj1Obj2 ↓↓↓↓ GiverTransferRecipientTheme You give auntie [the peach]. 2 Verb ↓ Transfer local? omitted? local Subj ↓ Giver omitted local? omitted? local Obj1 ↓ Recipient Obj2 ↓ Theme ni3gei3yi2 2PSgiveauntie

30 Lexical Unit gei3 Giver Recipient Theme How to recover the omitted argument, in this case the peach? The Transfer Frame Giver Recipient Theme Manner Means Place Purpose Reason Time (DNI) Discourse & Situational Context child mother auntie peach table omitted Obj2 ↓ Theme

31 Best-fit example with theme omitted Oh (go on)! You give [auntie] [that]. 3 Verb ↓ Transfer local? omitted? local omitted Subj ↓ Giver omitted local? omitted? local Obj1 ↓ Recipient Obj2 ↓ Theme aoni3gei3ya EMP2PSgiveEMP

32 Lexical Unit gei3 Giver Recipient Theme How to recover the omitted argument, in this case the aunt and the peach? The Transfer Frame Giver Recipient Theme Manner Means Place Purpose Reason Time (DNI) Discourse & Situational Context child mother auntie peach table omitted Obj2 ↓ Theme omitted Obj1 ↓ Recipient

33 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

34 The context model tracks accessible entities, events, and utterances Discourse & Situational Context Discourse01 participants: Eve, Mother objects: Hands,... discourse-history: DS01 situational-history: Wash-Action Discourse:

35 Each of the items in the context model has rich internal structure Situational History:Discourse History: Participants:Objects: Discourse: Wash-Action washer: Eve washee: Hands DS01 speaker: Mother addressee: Eve attentional-focus: Hands content: {"are they clean yet?"} speech-act: question Eve category: child gender: female name: Eve age: 2 Mother category: parent gender: female name: Eve age: 33 Hands category: BodyPart part-of: Eve number: plural accessibility: accessible

36 Analysis produces a semantic specification Linguistic Knowledge Utterance Discourse & Situational Context Semantic Specification World Knowledge Analysis “ You washed them ” WASH-ACTION washer: Eve washee: Hands

37 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!

38 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)

39 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.

40 Two perspectives on grammar learning Computational models 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 Developmental evidence Prior knowledge –primitive concepts –event-based knowledge –social cognition –lexical items Data-driven learning –basic scenes –lexically specific patterns –usage-based learning

41 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

42 Context Eve washer Wash-Action Hands washee Discourse Segment addressee attentional- focus Analysis draws on constructions and context before MeaningForm you Addressee washer Wash-Action washed washee ContextElement them

43 Learning updates linguistic knowledge based on input utterances Learning Discourse & Situational Context Linguistic Knowledge Analysis Utterance Partial SemSpec World Knowledge

44 Context Eve washer Wash-Action Hands washee Discourse Segment addressee attentional- focus Context aids understanding: Incomplete grammars yield partial SemSpec MeaningForm you Addressee washer Wash-Action washed washee ContextElement them

45 Context Eve washer Wash-Action Hands washee Discourse Segment addressee attentional- focus Context bootstraps learning: new construction maps form to meaning MeaningForm you AddresseeWash-Action washed ContextElement them before washer washee

46 Context bootstraps learning: new construction maps form to meaning MeaningForm you AddresseeWash-Action washed ContextElement them before washer washee YOU-WASHED-THEM constituents: YOU, WASHED, THEM form: YOU before WASHED WASHED before THEM meaning: WASH-ACTION washer: addressee washee: ContextElement

47 Grammar learning: suggesting new CxNs and reorganizing existing ones reinforcement reorganize merge join split Linguistic Knowledge Discourse & Situational Context Analysis Utterance Partial SemSpec World Knowledge hypothesize map form to meaning learn contextual constraints

48 Challenge: How far up to generalize Eat rice Eat apple Eat watermelon Want rice Want apple Want chair Inanimate Object Manipulable Objects Manipulable Objects Unmovable Objects Food Furniture Fruit Savory Chair Sofa apple watermelon rice

49 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

50 When does the learning stop? 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) Bayesian Learning Framework Schemas + Constructions SemSpec Analysis +Resolution Context Fitting

51 Intuition for MDL S -> Give me NP NP -> the book NP -> a book S -> Give me NP NP -> DET book DET -> the DET -> a 51 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

52 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

53 Usage-based learning: comprehension and production reinforcement (usage) reinformcent (correction) reinforcement (usage) hypothesize constructions & reorganize reinforcement (correction) constructicon world knowledge discourse & situational context simulation analysis utterance analyze & resolve utterance response comm. intent generate

54

55 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

56 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?

57 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

58 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!

59 Grammar learning : hypothesizing new constructions and reorganizing them reinforcement reorganize merge join split Linguistic Knowledge Discourse & Situational Context Analysis Utterance Partial SemSpec World Knowledge hypothesize map form to meaning learn contextual constraints

60 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

61 Understanding an utterance in context: analysis and simulation Linguistic Knowledge Simulation Utterance Discourse & Situational Context Semantic Specification World Knowledge Analysis Neural Theory of Language (Feldman, 2006)


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