The Function and Characteristics of a Cognitive ... - David Vernon

An Introduction to 

Artificial Cognitive Systems 

David Vernon 

Institute for Cognitive Systems 

Technical University of Munich 

www.vernon.eu 

Copyright © 2012 David Vernon

Lecture 3 

Cognitive Architectures 

The Function and Characteristics of a Cognitive Architecture 


Cognitive Architectures 

1. The function and characteristics of a cognitive architecture 

- The cognitivist and emergent perspectives 

- Desirable characteristics 

- Facets of a cognitive architecture: 

+ component functionality 

+ component interconnectivity 

+ system dynamics 

2. A survey of cognitive architectures 

3. Requirements for a developmental cognitive architecture 

4. A case study: the iCub cognitive architecture 


COGNITION 

Cognitivist 

Systems 

Hybrid 

Systems 

Emergent 

Systems 

Cognitive 

Architecture 

The term originated with the 

work of [Newell et al. 1982] 

Connectionist 

Approaches 

Dynamical 

Approaches 

Enactive 

Approaches 

Copyright © 2012 David Vernon 

[Vernon, Metta, Sandini 2007]

Cognitivist cognitive architectures 

Attempts to create Unified Theories of Cognition (UTC): 

UTCs cover a broad range of cognitive issues: 

• Attention 

• Memory 

• Problem solving 

• Decision making 

• Learning 

• … 

from several aspects 

• Psychology 

• Neuroscience 

• Computer Science 

• … [Byrne 03] 


Cognitivist Cognitive Architecture 

An embodiment of a scientific hypothesis about those aspects of 

human cognition that are 

relatively constant over time and 

relatively independent of task 

[Ritter & Young 01] 



Generic computational model: 

• Not domain-specific 

• Not task-specific 

Knowledge provides the required specificity 

Cognitive Architecture + Knowledge = Cognitive Model 

[Lehman et al 97, also Anderson & Labiere 98, Newell 90] 



• Theory of the fixed set of mechanisms and structures 

• Needs content to get behaviour 

architecture 

for 

architecture 

for 

TASK 

APPLICATION 

HARDWARE 

content 

for 

content 

for 

BEHAVIOR = ARCHITECTURE X CONTENT 

Factor out what’s common across cognitive behaviours 

across the phenomena explained by micro-theories 

Lehman et al 97, also Anderson & Labiere 98, Newell 90 



Overall structure and organization of a cognitive system 

• Essential Modules 

• Essential relations between these modules 

• Essential algorithmic and representational details in each module 

[Sun 2007] 


[GMU-BICA Architecture: Samsonovich 2005]


Commitment to formalisms for 

• Short-term & long-term memories that store the agent’s beliefs, goals, 

and knowledge 

• Representation & organization of structures embedded in memory 

• Functional processes that operate on these structures 

• Performance / utilization 

• Learning 

• Programming language to construct systems embodying the architectures 

assumptions 

[Langley 05, Langley 06, Langley et al. 09] 


Emergent Cognitive Architecture 

Emergent approaches focus on development 

• From a primitive state 

• To fully cognitive state, over the system’s lifetime 



The cognitive architecture is the system’s 

phylogenetic configuration 

• The basis for ontogenesis: growth and development 

– Innate skills 

– Core knowledge (cf. Spelke) 

• A structure in which to embed mechanisms for 

– Perception 

– Action 

– Adaptation 

– Anticipation 

– Motivation 

– … Development of all these 



Focus on 

• Autonomy-preserving anticipatory and 

adaptive skill construction 

• The morphology of the physical body 

in which the architecture is embedded 


Desirable Characteristics of a 

Cognitive Architecture 


Desirable Characteristics 

Desiderata for Cognitive Architectures [Sun 2004] 

1. Ecological realism 

2. Bio-evolutionary realism 

3. Cognitive realism 

4. Inclusiveness of prior perspectives 



Concurrent conflicting goals 

Ecological realism 

Everyday activities 

Embodied 


[Sun 2004]


Bio-evolutionary realism 

Human intelligence reducible to 

model of animal intelligence 


[Sun 2004]


Human psychology 

Cognitive realism 

Human neuroscience 

Philosophy 



Draw on older models 

Prior perspectives 

Subsume older models 

Supercede older models 


[Sun 2004]


Act & React … 

Simple conceptual schemas 

Behavioural Characteristics 

Simple weighing of alternatives 

Temporal sequence of actions 

Gradually-learned routine behaviours 

… trial-and-error adaptation 


[Sun 2004]


Implicit bottom-up learning 

Cognitive Characteristics 

Explicit symbolic learning 

Functional or physical modularity 


[Sun 2004]


Cognitive architectures: Research issues and challenges 

Cognitive architectures: 

Research issues and 

challenges 

1. Recognition & categorization 

2. Decision-making & choice 

3. Perception & situation assessment 

4. Prediction & monitoring 

5. Problem solving & planning 

6. Reasoning & belief maintenance 

7. Execution & action 

8. Interaction & communication 

9. Remembering, reflection, & learning 

[Langley et al. 2009] 



The importance of cognitive architectures … 

The importance of 

Cognitive architectures: 

An analysis based 

On Clarion 

1. Perception 

2. Categorization 

3. Multiple representations 

4. Multiple types of memory 

5. Decision making 

6. Reasoning 

7. Planning 

8. Problem solving 

9. Meta-cognition 

10.Communication 

11.Action control and execution 

12.Several types of learning 

[Sun 2007] 

The importance of the interconnectivity between these processes 



Cogaff Cognitive Architecture Schema 

[Sloman 2000] 

H-Cogaff Cognitive Architecture 

[Sloman 2001] 



Cognitive Architectures of Developmental Systems 

[Krichmar & Edelman 2005, 2006] 

1. Address connectivity and interaction between circuits/regions in the brain 

2. Effect perceptual categorization, without a priori knowledge 

(a model generator, rather than a model fitter, cf [Weng 04]) 

3. Embodied & capable of exploration 

4. Minimal set of innate behaviours 

5. Value system (set of motivations) to govern development 


Facets of a Cognitive Architecture 

• Component functionality 

• Component interconnectivity 

• System dynamics 



• Component functionality 

– Specification 

• Functionality 

• Theoretical foundations 

• Computational model 

• Information representation 

• Functional model (e.g. functional decomposition) 

• Data model (e.g. data dictionary or ER diagram) 

• Process-flow model (e.g. DFD diagram) 

• Behavioural model (e.g. State transition diagram) 

• Interface: input, output, protocols 

– Design choices: algorithms and data-structures 

– Implementation 

– API specification 



• Component interconnectivity 

– Data flow 

– Control flow 




– Cognitivist cognitive architectures 

• Add knowledge to determine the dynamics and flow of information 

– Emergent cognitive architectures 

• Not so straightforward … can’t just add knowledge 




– Emergent cognitive architectures 

• Dynamics result from interaction between the components 

– Driven by an embedded value system that governs the developmental 

process 

– Not by explicit production rules that encapsulate prior declarative and 

procedural knowledge 

• Need to specify the interactions between components 

– Small ensembles (at least) 

– Whole system (ideally) 

• This is a tough challenge 

– Assemblies of loosely-coupled concurrent processes 

– Operating asynchronously 

– Without a central control unit 

– Dynamics depend on circular causality 


• Organizational decomposition 

• Explicit inter-connectivity 

• Representational formalism 

• Algorithmic formalism 

Learn 

Perceive 

COGNITION 

Anticipate 

Cognitivist 

Systems 

• Framework in which 

to embed knowledge 

• Memories 

• Formalisms for learning 

• Programming mechanism 

Adapt 

Hybrid 

Systems 

Act 

Emergent 

Systems 

Phylogeny - basis for development: 

• Innate skills 

• Core knowledge 

• Formalism for autonomy 

• Formalism for development 


Recommended Reading 

Langley, P.: Cognitive architectures and general intelligent systems. 

AI Magazine 27(2), 33–44 (2006). 

Langley, P., Laird, J.E., Rogers, S.: Cognitive architectures: 

Research issues and challenges. Cognitive Systems Research 

10(2), 141–160 (2009). 

Sun, R.: The importance of cognitive architectures: an analysis 

based on clarion. Journal of Experimental & Theoretical Artificial 

Intelligence 19(2), 159–193 (2007). 

Sun, R.: Desiderata for cognitive architectures. Philosophical 

Psychology 17(3), 341–373 (2004).

The Function and Characteristics of a Cognitive ... - David Vernon

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