Post on 21-Feb-2016
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The Development of Tool Use in Infancy
Talk OverviewBackground: Understand infant cognitive developmentThe Problem of Tool Use:
What is requiredWhat develops
Mechanisms of Development: Behavioural schemas (Six mechanisms)Representations (Redescription) Linking Two tracks
Reflection, and Direction for Roboticists
Psychology Robotics research
Timeline of Development
Birth 6 9 12 15 18 24 months
Free Play: stereotypical accommodative relational simple relational functional relational
Overlapping waves (Siegler)
Timeline of Development
Free Play: stereotypical accommodative relational
Problem solving: support string stick radial grasp shapes in slots
Birth 6 9 12 15 18 24 months
simple relational functional relational
Two essential aspects always present Play: vary situations, performance, discover how it works Problem Solving: discover means good for particular goals
The Problem of Tool Use Selecting the right tool or tools Spatially arranging the right relationships
(between tools and target objects) Performing the appropriate manipulations Degrees of Freedom Solve by
Forward Search Forward Search with Heuristics Means-end
What Develops in Infants? Planning seems to be present early
Some improvements in Memory, Backtracking, Inhibition
Development of Schemas (≈ Planning Operators) Sensorimotor Schema
Development of Representations Objects Space, spatial relationships Actions ….
2
1
What Develops in Infants? Planning seems to be present early
Some improvements in Memory, Backtracking, Inhibition
Development of Schemas (≈ Planning Operators) Sensorimoto
Development of Representations Objects Space, spatial relationships Actions ….
2
1
Mechanisms M1 Repetition M2 Variation and selection M3 Differentiation M4 Composition M5 Modularisation M6 Decomposition
Mechanisms M1 Repetition M2 Variation and selection M3 Differentiation M4 Decomposition M5 Composition M6 Modularisation
Opportunistic
Where schema can Leads to discoveries (affordance) (play)
Mechanisms M1 Repetition M2 Variation and selection M3 Differentiation M4 Decomposition M5 Composition M6 Modularisation
Parameter variation Understand effects Generate new results Especially at difficulty Transition periods
Mechanisms M1 Repetition M2 Variation and selection M3 Differentiation M4 Decomposition M5 Composition M6 Modularisation
Branching in behaviour graph
Unexpected result Find preconditions Adjust motor action
Branching in behaviour graph
Mechanisms M1 Repetition M2 Variation and selection M3 Differentiation M4 Decomposition M5 Composition M6 Modularisation
Borrowed movement too crude
Refine parts Flexible reassembly
Mechanisms M1 Repetition M2 Variation and selection M3 Differentiation M4 Decomposition M5 Composition M6 Modularisation
Behaviour graph (join)
Simple sequence Hierarchical control
Mechanisms M1 Repetition M2 Variation and selection M3 Differentiation M4 Decomposition M5 Composition M6 Modularisation
Refine by repetition, variation and selection, produce a “smooth atom”
Ready to be used as subunit (for ongoing development)
Behaviour graph (join)
Stereotypical (Without Objects)1. Arm wave (100%): rapid flapping from shoulder
(surface slapping, waving objects/banging)
2. Finger flex (100%); flexion and extension of all four fingers
( exploratory behaviours with objects)
3. Hand rotate (90%) and flex (80%): a rhythmic rotation, bending and extending of the wrist
(object exploration?)
4. Clap hands together (75%)
( banging objects together) (85%)
5. Finger rotate (15%): similar to turning a large dial
(rotation of lids/dials?)
Single Objects Reach + Grasp Developing the Stereotypical
Behaviours with Objects: Waving a rattle Catch/release or scratch or squeezing an object, or crushing (e.g. paper)
(differentiation (M3), variation and selection (M2)) Multi-sensory Object Exploration Hand-Surface interaction
Object-Object Object-surface object-object Obstacle removal Support String Lever Stick ( the magic happens here ) Fitting Shapes into Slots (peg-in-hole task) Spoon-feeding (and other objects with handles)
Reinforcement learning
Timeline of Development
Free Play: stereotypical accommodative relational
Problem solving: support string stick radial grasp shapes in slots
Birth 6 9 12 15 18 24 months
simple relational functional relational
Overlapping waves (Siegler)
Really interesting part
stereotypical single object object-object
DONE
Representations (Objects, Space, …) Transfer as a proxy
Brown: Level of representation rather than age
determines transfer efficiency
Representations (Objects, Space)1. Coarse to Fine• Some situations generalise very well, and immediately • Sometimes over-generalise
(scale errors, incompatible shapes)
2. Context Specific to General3. Integration of Fragmentary Representations
Representations (Objects, Space)1. Coarse to Fine2. Context Specific to General• Some situations, do not generalise well at all• Spoon for self-feeding,
or for directing to another object• hand in a slot vs. posting a disk
3. Integration of Fragmentary Representations
Representations (Objects, Space)1. Coarse to Fine2. Context Specific to General1. Integration of Fragmentary Representations
“perception leads to multiple representations that may be recruited for different tasks”
4-month-olds perceive 3D form of rotating wireframes 6-month-olds “complete” solid 3D objects 18-month-olds still use fragmentary representations 24-month-olds 3D whole-object geometric representations
Advantages of fragmentary / task specific representations:• Simple space which for particular task• When another seems more appropriate
switch representation
Linking TracksSensorimotor
& Representation
MOVING OF MOUTH
EDGES
MOVING OF CONTAINER
EDGES
Container(object)
Push(action)
inside(spatial relationship)
Higher orderconcept
broken(object state)
Reflection 1. Planning present early, but few schemas (planning operators)
2. Initial Knowledge is Fragmentary and Incomplete
“to understand is to invent”, + schedule
3. Infants Learn Slowly, but Thoroughly
representations slow to change
4. Generalisation Depends on Representation
What are infants good and bad at? Good: build on what they know, try out, refine, assimilate Bad: make big leaps take several months
Emulating in a Robot…1. Start with Few Schemas, to Get a Lot
(Crucial to implement the Mechanisms)
2. Representations Must Develop Gradually
3. Interaction Between the Concrete and Abstract Tracks Difficult but Crucial (structural bootstrapping) Addressing the main mystery of development
4. Guiding Examples and Benchmarks for Development
Advancing the ScienceMany take “inspiration” from infants:
Affordances, intrinsic motivation, play
Need to: Model whole development, e.g. from 6 to 18 months
Aim for Same Behaviour How do they explore a space? How is old knowledge re-used? How robust is the behaviour? Representation
Psychology Robotics
Advancing the Science
Modelling:
Means-end behaviours
XXX
X
Experiments:
Get training into lab