Initiative in Dialogue (draft) Mark Core. An Informal Definition OED.com: to take the initiative: to take the lead, make the first step, originate some

Initiative in Dialogue (draft)

Mark Core

An Informal Definition

• OED.com: to take the initiative: to take the lead, make

the first step, originate some action• Sometimes referred to as “control”• dialogue initiative identifies who is leading the dialogue

at any given point

Why do people study initiative?

• Dialogue System Builders• for some applications, system may need to reason

about whether to take the initiative• systems need to take and give away initiative smoothly

like humans• system acts differently when it does and does not have

initiative

• Linguists• open question: what factors influence when dialogue

participants take initiative

Outline

• Defining and Annotating Initiative• Discourse Structure• Whittaker and Stenton• Strayer and Heeman• Linell et al.

• What is Known about Initiative• Initiative and Current Dialogue Systems• Going Beyond Initiative

Discourse Structure and Initiative

• “dialogue initiative ... tracks the lead in determining the

current discourse focus” (Chu-Carroll and Brown 1997,

p. 263)• topic-based segmentation – who initiated the topic.

Grosz and Sidner (1986)• dialogue moves – who produced an initiating move.

Grosz and Sidner (1986)

• Discourse grammar (syntax)• Discourse => Discourse_Segment+

• Discourse_Segment => utterance+

• Discourse grammar (semantics)• there is one unique ‘foundational’ purpose to the

dialogue and each discourse segment• meant to be recognized by listener• the discourse segment purposes (DSPs) support the

discourse purpose• utterances support discourse support the DSP

Structural Relations

• dominance: discourse is hierarchical. one DSP may be

intended to provide part of the satisfaction of another• satisfaction-precedence: order of DSPs may be significant

E: First you have to remove the flywheel....

loosen the two allen head setscrews...

A: I can only find one screw. Where’s the other one?

....

A: I can find them both now

E: Use the wheelpuller. Do you know how to use it?

...

E: The wheel should slide off [p. 186]

DS1

DS2

DS3

Attentional State

• focus spaces – contain salient entities (mentioned

explicitly or implicitly)• Entities could be properties, objects, relations, as well as

the discourse segment purpose• Let’s just look at objects

Focus Space Stack

E: First you have to remove the flywheel....

loosen the two allen head setscrews...

A: I can only find one screw. Where’s the

other one?

....

A: I can find them both now

E: Use the wheelpuller. Do you know

how to use it?

...

E: The wheel should slide off

DS1

DS2

DS3

flywheel

screw1

screw2

FOCUS SPACE STACK

screw1screw 2wheelpuller

DS1

DS2

DS3

Dialogue Moves and Games

• Dialogue Moves • also called speech acts or dialogue acts• capture intention behind an utterance • examples

• initiating: e.g., command, statement, question • responding: acknowledgement, answer, accept, reject

• Dialogue Games• start with an initiating move and end when the goal of that

move is accomplished or abandoned• games can be nested

[1] T: Do you still believe [your answer]?[2] S: I suppose not. [3] But doesn’t I=V/R?[4] T: Yes. That is true.[5] S: because V=IR[6] S: So why doesn‘t I = 75 / the resistence?[7] T: If P=IV, then you know that I = P/V. [8] I can only equal P/R if R=V. [9] Do you have a reason to believe that

R=V? [10] S: no

Dialogue Games Example

Complimentary Approaches

• Can group dialogue games based on topic• In tutoring ‘how to measure current’ we can group

dialogue games around the topics:• preparing the circuit (turn off power and break circuit)• connect leads across break (+ and – leads must be

connected correctly)

Whittaker and Stenton (1988)

• Simpler procedure for initiative assignment• Use four dialogue moves

• Assertions – “Declarative utterances used to state facts” • Commands • Questions• Prompts – “Utterances which did not express propositional

content, such as Yeah, Okay, Uh-huh”• Initiative assignment

• Assertion – speaker has initiative unless responding to a

question• Command – speaker has initiative• Question – speaker has initiative unless responding to a

question or command• Prompt – hearer has initiative

Walker and Whittaker (1990)

• “third person and one anaphors cross [these] boundaries

extremely rarely” p. 73-74• discourse segment boundaries marked by initiative

changes

Strayer and Heeman (2001)

• Compared initiative (annotated with Whittaker and

Stenton’s rules) to dialogue structure (as defined by

Grosz and Sidner)• Whittaker and Stenton rules are more fine-grained than

Grosz and Sidner segmentation• Forward Acknowledgments: listener takes initiative by

completing the speaker’s utterance• Other-Contributions: listener and speaker building

utterances together • Usually initiative goes back to the original speaker after

the interjection

Linell et al. (1988)

• each utterance is ranked based on how much “they can

be regarded as governing or steering the ensuing

dialogue and as being governed or commanded by the

preceding dialogue” p. 419• highest rank (6): not a response in any way but requires

a response from the listener• lowest rank (2): invite no response and give no more

information than required

Whittaker and Stenton (again)

• Whittaker and Stenton (1988)• benefits

• relatively simple to annotate• correlates well with discourse structure• gives us insight into “taking” and “giving away” initiative• extendable (consider additional dialogue moves)

• drawbacks• does not account for answers giving more information than

requested• never considers clarification requests as taking initiative• redundant if you know discourse structure

Outline




• Distinguish between types of control shifts (i.e., speaker

2 takes initiative after...)• Abdication: speaker1 utters a prompt signaling initiative

is released• Repetition/Summary: speaker1 signals the end of their

contribution with a repetition or summary• Interruption: speaker1 has not invited speaker2 to take

initiative• Rationale: listener knows a relevant fact, listener detects

a problem in the speaker’s proposal, or listener finds the

utterance ambiguous


Finance Support Pump-

Phone

Pump-

Chat

Turns/Seg 7.49 8.03 15.68 11.27

Exp-

Initiative

60% 51% 91% 91%

Abdication 38% 38% 45% 28%

Summary 23% 27% 7% 6%

Interrupt 38% 36% 48% 67%

Guinn (1996)

• used simulated conversations to argue that the most

efficient problem-solving dialogues are those where the

participant who knows the most about the current

subtask takes initiative

Distribution of Expert Initiative

Domain Expert Control

Finance 60%

Computer Support 51%

Pump Repair 91%

TRAINS-93 39.5%

Airline 58.1%

Maptask 86.6%

Switchboard 59.9%

Socratic Tutoring 90%

Didactic Tutoring 79%

Initiative and Learning Gain

0

10

20

30

40

50

0 5 10 15 20 25 30 35 40

Learning Gain

% Student Initiative

Pearson’s r = -.0689, n=23, NS

Initiative Shifts

• Chu-Carroll and Brown (1997)• Explicit cues• Discourse cues

• silence, repetitions, prompts, questions, obligation

fulfilled• Analytical cues

• invalid action/belief, sub-optimality, ambiguity

• Giving more information than requested

Factors affecting initiative

• Individual or joint goals?• Collaborative or competitive task?• Distribution of knowledge/expertise• Complexity of task• Task-based roles • Social roles• Social projection (face)• Group discussion v. one-on-one• Mediation/modality

Outline



Horvitz (1999)

• email reading system (graphical) – based on the content

of the email should the system (1) bring up the calendar,

(2) ask the user first, (3) do nothing• utility-based approach – penalties for interrupting user,

bringing up calendar unnecessarily, and reward for

bringing up the calendar when needed

Simple Speech-based Systems

• Here, initiative affects the system questions:• system initiative: “What city do you want to leave from?”• user initiative: “How may I help you?”

• initiative also affects how the system deals with extra

informatione.g., S: What city do you want to leave from?

U: LA on November 17th

• system initiative: ignores extra info• mixed/user initiative: processes all information

• the major factor is speech recognition performance

Tutorial Dialogue Systems

• Tend to be system initiative although sometimes

students can ask questions about definitions: “What is a

CPU?”• EDGE system (Cawsey 1989)

• if user question is related to a presentation goal, system

will request that the user wait

• Duke Programming Tutor (Keim et al. 1997)• topics picked on basis of

• believed student understanding• importance of topic• distance from current topic• how many times topic has been discussed• student interest

Outline



Tutorial Dialogue Systems

• (Core et al. 2003) study showed no relationship between

initiative and learning• Shah (1997) found more student initiative in students’ first

sessions• Graesser and Person (1994)

• in the first half of a course, found a negative correlation

between number of student questions and exam scores• in second half of course, found a positive correlation

between exam scores and proportion of student questions

that were deep-reasoning and knowledge-deficit

questions

Task Initiative

• Who has initiative can be quite independent of what’s

happening with the task (e.g., putting together the water

pump, learning physics)• (Chu-Carroll and Brown 97) & (Jordan and Di Eugenio

97)• If the dialogue concerns a task, it is possible to lead the

dialogue but not contribute to the task• Chu-Carroll and Brown separate these ideas into

dialogue initiative and task initiative

Chu-Carroll and Brown Example

S: I want to take NLP to satisfy my seminar course

requirement

Who is teaching NLP?

A1: Dr. Smith is teaching NLP

A2: You can’t take NLP because you haven’t taken AI,

which is a prerequisite for NLP.

A3: You can’t take NLP because you haven’t taken AI,

which is a prerequisite for NLP. You should take

distributed programming to satisfy your requirement,

and sign up as a listener for NLP.

Simple Task Initiative

• MIMIC (Chu-Carroll and Nickerson 2000)

• simple spoken dialogue system (for movie

information)• task initiative means system gives directions• e.g., “Please say the name of the movie or theatre

or town you would like information about”• task initiative means system makes suggestions• e.g., “Terminator is not playing at <theatre>

Terminator is playing at <alternative theatre> at <time1>

• Mixed-initiative MIMIC system outperformed system-

initiative MIMIC (better user satisfaction and task

efficiency)

Chu-Carroll and Nickerson (2000)

• Mixed-initiative MIMIC reasons about cues• TakeOverTask (user gives more info than requested)

• NoNewInfo• InvalidAction/InvalidActionResolved• AmbiguousAction/AmbiguousActionResolved

Future Work

• “Although a system needs to reason about how helpful it

needs to be, it is unclear whether this can be done

through a single variable [task initiative] that is tied to

dialogue initiative” (Strayer and Heeman p. 7 of pdf)• How to apply this principle to more complex domains

such as tutoring• student model contains all facts about domain• student has task initiative if he demonstrates knowledge

of such a fact• also if student recognizes their own error• may want to model hints which to various degrees give

away the answer

Documents

Initiative in Dialogue (draft) Mark Core. An Informal Definition OED.com: to take the initiative: to take the lead, make the first step, originate some