Studying cerebral organization through embodied artificial evolution

1
Studying cerebral organization throughembodied
artificial evolution

• Joris Janssen, Twan Goosen,
• Ida Sprinkhuizen-Kuyper, and Pim Haselager

1st NSVKI Student Conference Nijmegen, 22 June
2007
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Overview
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionOverview

• Introduction
• Research questions
• Experimental Setup
• Robot Design
• Task Ecological Niche
• Control structure Evolution
• Results
• Fitness
• Clustering
• Symmetry
• Fitness II
• Discussion
• Hemispheres
• Symmetry vs. Asymmetry

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Introduction
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionIntroduction

• Cerebral lateralization left and right part of
  human brain not the same
• Cerebral lateralization has had a lot of
  attention
• Cognitive psychology
• Neuropsychology
• Evolutionary biology
• Focus on
• What is lateralized?
• Not on origin (why?) of lateralization

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Research questions
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionResearch questions

• Two questions
• Why do we possess two hemispheres?
• Why are some of the functions of the brain
  organized symmetrically and others
  asymmetrically?
• gtgt actually two questions
• - why some asymmetrically?
• - why some symmetrically?

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Hypotheses
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionResearch questions

• Two hemispheres
• Back-up in event of injury
• gtgt unlikely brain not that plastic
• Related to symmetrical body plan

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Hypotheses
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionResearch questions

• Asymmetrical functions less neural space

symmetrical
asymmetrical
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Hypotheses
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionResearch questions

• Why then symmetrical functions?
• Found in all kinds of species
• Evolutionary advantage less information needs to
  be integrated
• Likely to develop easier/faster

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Summary
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionResearch questions

• Two hemispheres
• Related to origin of symmetrical body plan
• Asymmetrically organized functions
• Require less neural space
• Symmetrically organized functions
• Easier/faster to develop

9
Overview
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionOverview

• Introduction
• Research questions
• Experimental Setup
• Robot Design
• Task Ecological Niche
• Control structure Evolution
• Results
• Fitness
• Clustering
• Symmetry
• Fitness II
• Discussion
• Hemispheres
• Symmetry vs. Asymmetry

10
Experimental setup
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionExperimental setup

• Needs
• Robots (symmetrical and asymmetrical)
• Task and environment
• Control structure
• Developmental mechanism evolution

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Robot design
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionRobot design
symmetrical
asymmetrical
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Task Ecological niche
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionTask Ecological niche

• Move around environment
• Cover as much distance as possible
• Avoid bumping into walls

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Control structure
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionControl structure Evolution
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Evolution
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolution Control structure
Evolution

• Evolution used to modify weights and biases
• First generation starts with random weights and
  biases
• Genetic algorithm
• Test individuals
• Select top 10 (out of 20)
• Generate 10 new ones out of 10 old ones (by
  mutating weights)

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Overview
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionOverview

• Introduction
• Research questions
• Experimental Setup
• Robot Design
• Task Ecological Niche
• Control structure Evolution
• Results
• Fitness
• Clustering
• Symmetry
• Fitness II
• Discussion
• Hemispheres
• Symmetry vs. Asymmetry

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Fitness of symmetrical group
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionFitness
Group with symmetrical body plan
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Fitness of asymmetrical group
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionFitness
Group with asymmetrical body plan
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Clustering
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionClustering
Edelman Tononi
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Clustering results
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionClustering
Analysis of variance over last 50 generations p
lt 0.001 R2 0.135
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Symmetry
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionSymmetry
Symmetrical processing
Asymmetrical processing
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Asymmetry
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionSymmetry
Analysis of variance over last 50 generations p
lt 0.001 R2 0.525
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Fitness II
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionFitness
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Summary
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionResults

• Symmetrical body plan results in more symmetrical
  control structure
• More clustering in symmetrical group
• Asymmetrical group performs better in the end
• Symmetrical group develops faster in the beginning

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Overview
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionOverview

• Introduction
• Research questions
• Experimental Setup
• Robot Design
• Task Ecological Niche
• Control structure Evolution
• Results
• Fitness
• Clustering
• Symmetry
• Fitness II
• Discussion
• Hemispheres
• Symmetry vs. Asymmetry

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Hemispheres
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionDiscussion

• Hypothesis symmetrical body plan results in two
  hemispheres
• Results Symmetrical body plan results in two
  clusters

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Asymmetry
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionDiscussion

• Hypothesis asymmetrical better performance since
  better use of neural space
• Results asymmetrical group performs better

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Symmetry
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionDiscussion

• Hypothesis symmetry less complex to develop
• Results symmetry develops faster

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Causality?
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionDiscussion
body plan structure
performance
control structure
control structure
body plan structure
performance
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Validity?
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionDiscussion

• Simulated model no valid equivalent of natural
  system
• But this research can
• .provide supporting evidence
• .lead to new ideas and insights

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Take home message
Janssen, Goosen, Sprinkhuizen-Kuyper, and
Haselager
Studying cerebral organization through embodied
artificial evolutionTake home message
Use robots as cognitive tools!