Albert Gatt LIN 1080 Semantics Lecture 13. In this lecture We take a look at argument structure and...
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- Slide 1
- Albert Gatt LIN 1080 Semantics Lecture 13
- Slide 2
- In this lecture We take a look at argument structure and
thematic roles these are the parts of the sentence that correspond
to the participants in the situation described thematic roles help
to classify the kinds of relations between entities (people,
things, places) in a situation
- Slide 3
- Classifying thematic roles Part 1
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- Some distinctions Mary hit John. Syntactic functions: Surface
subject: Mary Surface object: John Thematic roles: Mary is the
AGENT in the situation John is the PATIENT
- Slide 5
- Some distinctions John was hit by Mary. Syntactic functions:
Surface subject: John Surface prepositional object: Mary Thematic
roles: Mary is still the AGENT in the situation John is still the
PATIENT Arguments with specific roles have typical syntactic
functions, but roles stay constant when the surface order
changes.
- Slide 6
- Thematic roles: AGENT doer or initiator of an action capable of
volitional behaviour typically animate Silvia cooked dinner. The
cat climbed the wall. Related to: ACTOR conceived as a more general
role AGENT is a kind of ACTOR ACTOR does not need to display
volition: The car ran over the hedgehog
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- Thematic roles: AGENT (cont) Some tests have been proposed for
AGENT-hood Jackendoff (1972): to test if a participant is an agent,
try adding some phrase that makes volition explicit John opened the
letter deliberately John opened the letter in order to read it
?John received the letter in order to read it
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- Thematic roles: PATIENT undergoes the effect of some action
often changes its state can be animate or inanimate The sun melted
the ice.
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- Thematic roles: PATIENT Jackendoff (1990) proposes the
following test: if it makes sense to ask What happened to X? then X
is probably the patient. Sue slapped John. What happened to John?
(He got slapped) The book was in the library. What happened to the
book? (Anomalous!) What happened to the library? (Anomalous!)
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- Thematic roles: THEME Entity which is moved by an action or
whose location or state is described need not be animate The book
is in the library. Some authors treat THEME and PATIENT as the same
role.
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- Thematic roles: EXPERIENCER Used for entities that display some
awareness of an action/ sensation/state not volitional, unlike
AGENT I feel sick. Jack saw the lion in the bushes.
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- Thematic roles: BENEFICIARY entity for whose benefit the action
was performed typically realised as complement of a for-PP Jackson
painted a picture for his wife
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- Thematic roles: INSTRUMENT the means by which an action is
performed often realised as complement of a with-PP He burst the
door with a sledgehammer
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- Thematic roles: LOCATION place where something is place where
action takes place typically realised as complement of a locative
PP (under, in, on) The tiger hid behind the curtain
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- Thematic roles: GOAL thing towards which something moves can be
literal or metaphorical movement John gave the letter to Mary She
told the Joke to her friends NB: some theorists refer to certain
GOALs as RECIPIENTs especially in the case of give and similar
verbs
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- Thematic roles: SOURCE the entity from which something moves or
originates can be literal or metaphorical typically realised in a
from-PP I got the idea from Jason. I come from Malta.
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- Problems with these classifications Different authors have
different views about what qualifies as what e.g. to some, there is
no distinction between PATIENT and THEME There are some ambiguous
cases: Margarita received a gift. GOAL? RECIPIENT?
BENEFICIARY?
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- Dealing with the ambiguity Jackendoff (1990): some roles are
more primary than others different roles belong to different levels
of interpretation thematic tier: describes spatial relations roles
include THEME, GOAL, SOURCE, LOCATION action tier: describes
ACTOR-PATIENT type relations main roles are therefore ACTOR/AGENT
and PATIENT, EXPERIENCER, BENEFICIARY, INSTRUMENT Sentences receive
an interpretation on both levels
- Slide 19
- Jackendoff (1990) Sue hit Fred. thematic tier: THEME (Sue) GOAL
(Fred) action tier: ACTOR (Sue) PATIENT (Fred) Bill entered the
room. thematic tier: THEME (Bill) GOAL (the room) action tier:
ACTOR (Bill) N.B. not all arguments need to be represented at both
levels!
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- Difficulties with thematic roles Intuitively, they are there,
but they are very difficult to delimit Classifications like
AGENT/PATIENT etc must allow for a lot of variation in what
qualifies. e.g. the child cracked the mirror is the mirror a
PATIENT? More serious problem: how to define each role. there needs
to be some semantic motivation i.e. we need to show that the
distinctions capture meaningful distinctions in a semantic
theory
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- Dowty (1991) Attempt to deal with the problem of defining
thematic roles correctly. Example: What does x have in common in: x
murders y, x nominates y x interrogates y Dowty: they have a set of
entailments in common x does a volitional act x causes an event to
take place involving y x moves or changes externally NB. These
entailments are carried by all the above sentences, and they all
feature the role of x
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- Dowty (1991) Proposed to view roles as prototypes rather than
define several roles, each crisply delimited, he proposed two basic
prototypes: Proto-Agent, Proto-Patient each prototype has a list of
characteristic entailments arguments in a sentence qualify as one
or the other to different degrees
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- Dowty (1991) Proto-Agent 1. volitional involvement in the event
or state 2. sentience / perception 3. causes an event or a change
of state in another participant 4. movement relative to the
position of another participant Proto-Patient 1. undergoes a change
of state 2. incremental theme 3. causally affected by another
participant 4. stationary relative to movement of another
participant
- Slide 24
- Degrees of thematic role-hood Under Dowtys conception, some
arguments will be more Proto-Agent-like than Proto-Patient-like
John cleaned the house has all the entailments of the Proto-Agent
John dropped the suitcase lacks volition, but has sentience The
storm destroyed the house lacks sentience and volition
- Slide 25
- Why thematic roles? Part 2
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- Thematic roles and argument selection There seem to be
systematic ways in which roles typically map to grammatical
functions e.g. EXPERIENCER is usually the subject PATIENT is
usually the object Roles therefore allow us to predict how
arguments are linked to the verb given its semantics. Often, a
theta-grid for a verb is proposed Crack: underlined role maps to
subject order of roles allows prediction of grammatical
function
- Slide 27
- Dowtys Argument Selection Principle if a verb takes a subject
and an object the argument with the greatest number of Proto-Agent
properties will be the one selected as subject; the one with the
greatest no. of Proto-Patient properties will be selected as
object.
- Slide 28
- Dowty on argument selection Corollary 1 of the ASP: if two
arguments have roughly equal numbers of Proto-Agent and
Proto-Patient properties, either one or both may be the direct
object Corollary 2 of the ASP: with a 3-place predicate (e.g.
give), the direct object will probably be the argument with the
greatest number of Proto- Patient properties
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- The rationale Dowtys model seems to have high predictive power.
e.g. In describing a shoot event, involving, we are likely to map
John to subject, the dog to object, the gun to a PP John has the
highest no. of Proto-Agent roles out of the dog and the gun, dog
has higher no. of Proto-Patient roles
- Slide 30
- Other thematic roles Proto-Agent and Proto-Patient are the
basic prototypes in Dowtys model the idea is to then view other
roles like EXPERIENCER etc as sharing some of the properties of a
Proto-Agent/Patient, but not all
- Slide 31
- Dowtys thematic role hierarchy Dowtys principles are meant as
(violable) constraints on how arguments of a verb are linked to it
syntactically. They also allow us to speak of candidacy for
subjecthood by degrees Proposed hierarchy: elements higher up have
more Proto-Agent properties, so more likely to be subjects AGENT
> INSTRUMENT EXPERIENCER > PATIENT > SOURCE GOAL
- Slide 32
- Summary Thematic roles are a crucial linking feature between
syntax and semantics In models like Dowtys, some attempts are made
to predict syntactic features (subject, object etc) from underlying
semantics