Initiative in Dialogue (draft)

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Initiative in Dialogue (draft)

• Mark Core

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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

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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

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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

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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.

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Grosz and Sidner (1986)

• Discourse grammar (syntax)
• Discourse gt Discourse_Segment
• Discourse_Segment gt 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

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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. Wheres 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
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Attentional State

• focus spaces contain salient entities
  (mentioned explicitly or implicitly)
• Entities could be properties, objects, relations,
  as well as the discourse segment purpose
• Lets just look at objects

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Focus Space Stack
DS1
DS1

• E First you have to remove the flywheel....
• loosen the two allen head setscrews...
• A I can only find one screw. Wheres 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

DS2
DS2
screw1 screw 2
wheel puller
DS3
DS3
flywheel screw1 screw2
FOCUS SPACE STACK
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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

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Dialogue Games Example
1 T Do you still believe your answer? 2 S
I suppose not. 3 But doesnt IV/R? 4 T
Yes. That is true. 5 S because VIR 6 S So
why doesnt I 75 / the resistence? 7 T If
PIV, then you know that I P/V. 8 I can
only equal P/R if RV. 9 Do you have a
reason to believe that RV? 10 S no
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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)

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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

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Walker and Whittaker (1990)

• third person and one anaphors cross these
  boundaries extremely rarely p. 73-74
• discourse segment boundaries marked by initiative
  changes

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Strayer and Heeman (2001)

• Compared initiative (annotated with Whittaker and
  Stentons 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 speakers utterance
• Other-Contributions listener and speaker
  building utterances together
• Usually initiative goes back to the original
  speaker after the interjection

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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

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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

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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

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Walker and Whittaker (1990)

• 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 speakers
  proposal, or listener finds the utterance
  ambiguous

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Walker and Whittaker (1990)
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
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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

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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
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Initiative and Learning Gain
Pearsons r -.0689, n23, NS
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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

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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

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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

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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

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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 information
• e.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

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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

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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

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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

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Task Initiative

• Who has initiative can be quite independent of
  whats 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

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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 cant take NLP because you havent taken
  AI,
• which is a prerequisite for NLP.
• A3 You cant take NLP because you havent 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.

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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 lttheatregt
• Terminator is playing at ltalternative theatregt at
  lttime1gt
• Mixed-initiative MIMIC system outperformed
  system-initiative MIMIC (better user satisfaction
  and task efficiency)

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Chu-Carroll and Nickerson (2000)

• Mixed-initiative MIMIC reasons about cues
• TakeOverTask (user gives more info than
  requested)
• NoNewInfo
• InvalidAction/InvalidActionResolved
• AmbiguousAction/AmbiguousActionResolved

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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