Chapter 1. Imitation: Thoughts about Theoriesin Imitation and Social Learning in Robots, Humans and Animals,
Nehaniv and Dautenhaln.
Course: Robots Learning from Humans
Geonmo Gu
Computer Theory and Application LaboratorySchool of Computer Science and Engineering
http://theory.snu.ac.kr
Soojin Jung
Cognitive PsychologyDepartment of Cognitive Science
Contents Introduction
The Correspondence Problem
Three theories Active Intermodal Mapping (AIM) Goal-Directed Imitation (GOADI) Associative Sequence Learning (ASL)
Contrasting 3 theories Issue 1: Effect-dependency Issue 2: Awareness
Questions for ASL model: about Intention
Conclusion & Discussion
2
Introduction Imitation as Transferred information between Agents (biological, computational or
robotic autonomous systems). Challenge in imitation theory:
HOW observation of action facilitates production of matching movements.
3
The Correspondence Problem The problem for one individual of producing behaviour that matches with behavior it
observes in another. The observer must formulate motor commands to match visual input
4
Observer Model
Visual Input
The Correspondence Problem The problem for one individual of producing behaviour that matches with behavior it
observes in another. The observer must formulate motor commands to match visual input
5
Observer Model
Visual Input
The Correspondence Problem The problem for one individual of producing behaviour that matches with behavior it
observes in another. The observer must formulate motor commands to match visual input
6
Model
Motor command
Observer
The Correspondence Problem
7
Observer ModelObserver Model
Visual Input
Visual information
Observer has Visual Information of model’s action Motor information (feeling) of observer’s action
The Correspondence Problem Observer has
Visual Information of model’s action Motor information (feeling) of observer’s action
8
Observer ModelObserver Model
Visual Input
NO Visual informationVisual information
The Correspondence Problem Observer has
Visual Information of model’s action Motor information (feeling) of observer’s action
9
Observer ModelObserver Model
Visual Input
Motor information (feeling)Visual information
The Correspondence Problem Observer has
Visual Information of model’s action Motor information (feeling) of observer’s action
10
ObserverModel
Motor information (feeling)Visual information
feeling
3 Theories on Imitation 1. Active Intermodal Mapping (AIM) 2. Goal-Directed Imitation (GOADI) 3. Associative Sequence Learning (ASL)
11
<AIM> <GOADI> <ASL>
3 Theories on Imitation 1. Active Intermodal Mapping (AIM) 2. Goal-Directed Imitation (GOADI) 3. Associative Sequence Learning (ASL)
12
<AIM> <GOADI> <ASL>
1. Active Intermodal Mapping (AIM) Visual representation Motor representation Supramodal representation
13
ObserverModel
Motor representationVisual representation
feeling
Supramodal representation
Organ relation
1. Active Intermodal Mapping (AIM) Visual information: adult’s tongue-protrusion Motor information: infant’s feeling Organ relation: tongue-beyond-lips
Organ: part of body. head, brows, tongue, lips
14
Facial imitation
Tongue-beyond-lips
1. Active Intermodal Mapping (AIM) Correspondence problem
15
3 Theories on Imitation 1. Active Intermodal Mapping (AIM) 2. Goal-Directed Imitation (GOADI) 3. Associative Sequence Learning (ASL)
16
<AIM> <GOADI> <ASL>
2. Goal-Directed Imitation The GOADI theory of imitation suggests that perceived actions are decomposed into a
series of ‘aspects’. Only some goal aspects are imitated; movement end-points and the manipulation of
objects are more likely to be imitated than either the effector or the movement path.
17
2. Goal-Directed Imitation Correspondence problem:
No special relationship between matching movements under GOADI. Goal imitation: if the movement most commonly associated with the perceived goal is
different from the movement of the model, then goal, but not movement, imitation will occur.
18
Perceived Action
CommonlyAssociatedMotor program
GoalRepresentation
ExtractedGoals
Structures of Models
19
Perceived Action
MotorCommands
SupramodalRepresentation
Perceived Action
CommonlyAssociatedMotor program
GoalRepresentation
AIM
GOADI
Perceived Action
Performance ofAction
ASL
3. Associative Sequence Learning Vertical associations Indirect vertical associations
20
3. Associative Sequence Learning Vertical Associations
A few may be innate The majority are formed in a Hebbian fashion.
21
3. Associative Sequence Learning Indirect vertical association
Word
22
smile
smile
3. Associative Sequence Learning Indirect vertical association
Word
23
3. Associative Sequence Learning Correspondence problem (imitation)
24
Observer Model
Visual Input
3. Associative Sequence Learning Correspondence problem
25
Observer Model
Visual Input
3. Associative Sequence Learning Correspondence problem
26
Observer Model
Visual Input
3. Associative Sequence Learning Correspondence problem
27
Observer Model
Visual Input
3. Associative Sequence Learning Correspondence problem
28
Observer Model
Visual Input
smile
3. Associative Sequence Learning Correspondence problem
29
Observer Model
Visual Input
smile
Summary• Correspondence problem
• Active Intermodal Mapping (AIM)
• Goal-Directed Imitation (GOADI)
• Associative Sequence Learning (ASL)
30
Contents Introduction
The Correspondence Problem
Three theories Active Intermodal Mapping (AIM) Goal-Directed Imitation (GOADI) Associative Sequence Learning (ASL)
Contrasting 3 theories Issue 1: Effect-dependency Issue 2: Awareness
Questions for ASL model: about Intention
Conclusion & Discussion
31
Contrasting 3 theories★ two criteria
32
Effector-dependency Awareness
Whether observation can support effector-dependent learning
Whether Imitation Learning can occur without awareness
Effector-dependency issue
• Some kinds of Training are not generalized to others.
ex) Right-Left hand using is not convertible (Bapi et al, 2000)
33
Explanation for Effector-dependency
34
Different predictions of 3 Theories on Effector-dependent observational learning
AIM GOADI ASL
Frequency None (always effector-independent)
Rare (Actions not encoded at global level)
Usual
Principal (transformed into) Supramodal representation
action “Effects" Visual experience paring with motor activation
Result various motor outputs
Goal-directed action ex) finger movement
Experiment: Effector-dependent learning by observation.
35
(Bird and Heyes, 2005; Heyes and Foster, 2002; Osman etal., 2005)
Direct link between Perception & Action
- Observers’ better performing(:typing speed) the finger movement sequence with using same finger of model’s
Explanation for Awareness
36
AIM GOADI ASLAwareness O O X / ?
Mechanism Active Goal-directed Automatic
Base not mentione
d
Goal-directed imitation’
theory
(on next slides)
Experimental Evidences for automatic imitation
1. Electrophysiological(MEP) study: Motor facilitation by action observation (Aziz-Zadeh et al., 2002; Maeda et al., 2002; Strafella and Paus,2000)
37
2. ‘Chameleon effect’ in social interaction(Chartrand and Bargh, 1999; Lakin and
Chartrand, 2003)
Questions for ASL model
38
• Intentional vs. incidental imitation
ASL Model is NOT considering - a representation of the model’s action goals, - role of amodal (non-sensory, non-motor)
representations of action.
Contrary to our introspective plausibility
Thoughts about the Intentionality issue
39
Relationship between intentional processing and the vertical associations mediating imitation
Without Intention,Movement observation Motor activation by ASL. Automatic process (e.g.: Hebbian learning.)normally INHIBITED to prevent overt imitation
With Intention,Disinhibition on vertical associationFormulation of verbal description of observed action.c.f) Vocabulary limitation : dancers and gymnasts’ special vocab uses.
Conclusion(part 2.)
40
model’s Goals explaining what is imitated,
Vertical Association explaining How imitation is achieved.
한 가지 모델만으로 모방 학습에 대해 설명할 필요는 없음 .
모방 학습 상황에 대한 이론으로서 , GOADI 와 ASL 이 상호보충적 설명 가능 .
Discussion#1. Is ‘Imitation’ Default of Human cognitive-behavior system? How broadly can it be applied over areas? (Social/ Functional / Evolutionary..)
#2.In the Goal-Directed ImitationThe goal of the imitator is to produce exactly the same body movement.Cases like this pose the correspondence problem, and yet GOADI is silent about how this problem may be solved.
41
Top Related