The Development of Tool Use in Infancy

1. The Development of Tool Use in Infancy

2. Talk Overview Background: Understand infant cognitive development The Problem of Tool Use: What is required What develops Mechanisms of Development: Behavioural schemas (Six mechanisms) Representations (Redescription) Linking Two tracks Reflection, and Direction for Roboticists Psychology Robotics research

3. Timeline of Development Birth 6 9 12 15 18 24 months Free Play: stereotypical accommodative relational simple relational functional relational Overlapping waves (Siegler)

4. Timeline of Development Birth 6 9 12 15 18 24 months Free Play: stereotypical accommodative relational simple relational functional relational Problem solving: support string stick radial grasp shapes in slots • Two essential aspects always present • Play: vary situations, performance, discover how it works • Problem Solving: discover means good for particular goals

5. 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

6. 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 • ….

7. 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 • …. 1 2

8. 2 1

9. Mechanisms • M1 Repetition • M2 Variation and selection • M3 Differentiation • M4 Composition • M5 Modularisation • M6 Decomposition

10. Mechanisms • M1 Repetition • M2 Variation and selection • M3 Differentiation • M4 Decomposition • M5 Composition • M6 Modularisation • Opportunistic • Where schema can • Leads to discoveries • (affordance) • (play)

11. 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

12. Mechanisms • M1 Repetition • M2 Variation and selection • M3 Differentiation • M4 Decomposition • M5 Composition • M6 Modularisation • Unexpected result • Find preconditions • Adjust motor action Branching in behaviour graph

13. Mechanisms • M1 Repetition • M2 Variation and selection • M3 Differentiation • M4 Decomposition • M5 Composition • M6 Modularisation • Borrowed movement too crude • Refine parts • Flexible reassembly Branching in behaviour graph

14. Mechanisms • M1 Repetition • M2 Variation and selection • M3 Differentiation • M4 Decomposition • M5 Composition • M6 Modularisation • Simple sequence • Hierarchical control Behaviour graph (join)

15. 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)

16. Stereotypical (Without Objects) • Arm wave (100%): rapid flapping from shoulder • (surface slapping, waving objects/banging) • Finger flex (100%); flexion and extension of all four fingers • ( exploratory behaviours with objects) • Hand rotate (90%) and flex (80%): a rhythmic rotation, bending and extending of the wrist • (object exploration?) • Clap hands together (75%) • ( banging objects together) (85%) • Finger rotate (15%): similar to turning a large dial • (rotation of lids/dials?)

17. 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

18. 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

19. Timeline of Development Birth 6 9 12 15 18 24 months Really interesting part Free Play: stereotypical accommodative relational simple relational functional relational Problem solving: support string stick radial grasp shapes in slots Overlapping waves (Siegler)

20. DONE single object object-object stereotypical

21. Representations (Objects, Space, …) • Transfer as a proxy • Brown: • Level of representation rather than age • determines transfer efficiency

22. Representations (Objects, Space) • Coarse to Fine • Some situations generalise very well, and immediately • Sometimes over-generalise (scale errors, incompatible shapes) • Context Specific to General • Integration of Fragmentary Representations

23. Representations (Objects, Space) • Coarse to Fine • 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 • Integration of Fragmentary Representations

24. Representations (Objects, Space) • Coarse to Fine • Context Specific to General • 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

25. Sensorimotor & Representation Linking Tracks

28. MOVING OF MOUTH EDGES MOVING OF CONTAINER EDGES

29. Container (object) Push (action) Higher order concept inside (spatial relationship) broken (object state)

30. Reflection • Planning present early, but few schemas (planning operators) • Initial Knowledge is Fragmentary and Incomplete • “to understand is to invent”, + schedule • Infants Learn Slowly, but Thoroughly • representations slow to change • 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

31. Emulating in a Robot… • Start with Few Schemas, to Get a Lot(Crucial to implement the Mechanisms) • Representations Must Develop Gradually • Interaction Between the Concrete and Abstract Tracks • Difficult but Crucial (structural bootstrapping) • Addressing the main mystery of development • Guiding Examples and Benchmarks for Development

32. Advancing the Science • Many 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

33. Advancing the Science Psychology Robotics Modelling: Means-end behaviours Experiments: Get training into lab   X   X X X