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Cognitive Robotics

Jeff KrichmarLecture 4

Outline

• How the Body Shapes the Way We Think– Ch. 4: Intelligent Systems: Properties and

Principles• Structured Programming• Lab 4:

– Stay the course– Follow the path.

• Mid-Term Project

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Real World Challenges

• Acquisition of information takes time.• Information acquired is limited.• Physical devices are subject to disturbances and

malfunctions.• Real-world is not characterized by clearly defined,

discrete states.• Embodied agents must handle multiple tasks in

parallel.• Embodied agents must act within the dynamics of the

real world.

Properties of Complete Agents

• Subject to the laws of physics.• Generate sensory stimulation through

interaction with the real world.• Affect the environment through

behavior.• Complex dynamical systems.• Perform morphological computation.

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Agent Design Principle 1The Three-Constituents Principle• 1) Definition of ecological niche.• 2) Desired behavior.• 3) Design of the agent.• Design Stances

– Niche and behavior given.– Niche given, behavior emerges.– Find a niche.

• Scaffolding– Structure our environment to make tasks easier.

• GPS, road signs, tools, etc.

Agent Design Principle 2The Complete-Agent

• When designing, we must think of thecomplete agent behaving in the real world.

• Psychology example– Modular view

• Cognition, perception, categorization, memory,attention, social interaction, learning, emotion, etc.

– Complete view• Different perspectives of the same set of processes.

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Agent Design Principle 3:Cheap Design

• Agents are built to exploit…– Properties of the ecological niche.– Characteristics of the interaction with the

environment.• Examples

– Swiss robots– Passive walkers

Passive Walkers

• Efficient Bipedal Robots Based on Passive Dynamic Walkers, Collins,et al., Science, 307:1082-1085, 2005

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Passive Walkers

• Efficient Bipedal Robots Based on Passive Dynamic Walkers, Collins,et al., Science, 307:1082-1085, 2005

Agent Design Principle 4Redundancy

• Intelligent agents must be designed insuch a way that…– Their different subsystems function on the

basis of different physical processes.– There is partial overlap of functionality

between subsystems.

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Degeneracy not Redundancy

• Degeneracy, the ability of elements thatare structurally different to perform thesame function or yield the same output.– “Degeneracy and complexity in biological systems”, GM

Edelman & JA Gally, PNAS, 2001, 98(24): 13763-13768.

Degeneracy at Different Levelsof Biological Organization

1. Genetic code (many different nucleotide sequences encode apolypeptide)

2. Protein fold (different polypeptides can fold to be structurallyand functionally equivalent)

3. Units of transcription (degenerate initiation, termination, andsplicing sites give rise to functionally equivalent mRNAmolecules)

4. Genes (functionally equivalent alleles, duplications, paralogs,etc., all exist)

5. Gene regulatory sequences (there are degenerate geneelements in promoters, enhancers, silencers, etc.)

6. Gene control elements (degenerate sets of transcriptionfactors can generate similar patterns of gene expression)

7. Posttranscriptional processing (degenerate mechanismsoccur in mRNA processing, translocation, translation, anddegradation)

8. Protein functions (overlapping binding functions and similarcatalytic specificities are seen, and "moonlighting" occurs)

9. Metabolism (multiple, parallel biosynthetic and catabolicpathways exist)

10. Food sources and end products (an enormous variety ofdiets are nutritionally equivalent)

11. Subcellular localization (degenerate mechanisms transportcell constituents and anchor them to appropriatecompartments)

12. Subcellular organelles (there is a heterogeneous population ofmitochondria, ribosomes, and other organelles in every cell)

13. Cells within tissues (no individual differentiated cell is uniquelyindispensable)

14. Intra- and intercellular signaling (parallel and convergingpathways of various hormones, growth factors, secondmessengers, etc., transmit degenerate signals)

15. Pathways of organismal development (development often canoccur normally in the absence of usual cells, substrates, orsignaling molecules)

16. Immune responses (populations of antibodies and other antigen-recognition molecules are degenerate)

17. Connectivity in neural networks (there is enormous degeneracyin local circuitry, long-range connections, and neural dynamics)

18. Mechanisms of synaptic plasticity (changes in anatomy,presynaptic, or postsynaptic properties, etc., are all degenerate)

19. Sensory modalities (information obtained by any one modalityoften overlaps that obtained by others)

20. Body movements (many different patterns of muscle contractionyield equivalent outcomes)

21. Behavioral repertoires (many steps in stereotypic feeding,mating, or other social behaviors are either dispensable orsubstitutable)

22. Interanimal communication (there are large and sometimesnearly infinite numbers of ways to transmit the same message,a situation most obvious in language)

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Agent Design Principle 5Sensory-Motor Coordination

• Structured stimulation is inducedthrough sensory-motor coordination.

Agent Design Principle 6Ecological Balance

• Given a task environment, there has tobe a match between the complexities ofthe agent’s sensory, motor, and neuralsystems.

• There is a balance or task distributionbetween morphology, materials, control,and environment.

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Morphological Computation• Certain processes are performed by the

body that free up brain processing.

Computation by Sensor Morphology

• The “Eyebot”– Based on arrangement of facets in the housefly.

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Agent Design Principle 7Parallel, Loosely Coupled Processes

• Intelligence is emergent from a largenumber of parallel processes.– Coordinated through embodied interaction

with the environment• Not “Sense, think, then act”.• Control is parallel, asynchronous, and

matched with the real-world.

Agent Design Principle 8Value

• Intelligent agents are equipped with avalue system which constitutes a basicset of assumptions about what is goodfor an agent.

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Value Systems

• Organisms adapt theirbehavior through valuesystems:– Non-specific,

modulatory signals tothe rest of the brain.

– Biases the outcome ofsynaptic efficacy in thedirection needed tosatisfy global needs.

Vertebrate Neuromodulatory Systems

• Raphe nucleus– Source of serotonin– Threat assessment (RED)

• Locus coeruleus– Source of norepinephrine– Novelty and saliency (ORANGE)

• SN & VTA– Source of dopamine– Reward and wanting (BLUE)

• Basal Forebrain– Source of acetylcholine– Attentional effort (GREEN)

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Foraging for Different Goals Basedon Internal Drives and Values

Hunger Thirst Progress

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Structured Programming

• Loops• Wait for Events• Switches

– If then [do this]– Else [do that]