A model of agent consciousness and its implementation Ivan Moura Neurocomputing, 69 (16-18) 2006 pp. 1984-1995

A model of agent consciousnessand its implementation

Ivan MouraNeurocomputing, 69 (16-18) 2006

pp. 1984-1995.

Outline

• Introduction• Varieties of consciousness• The global workspace model• Identifying computational correlates of consciousness• A sequential abstract machine• A multithreaded virtual machine• Implementing computational correlates of conscious-ness

• Conclusion• Discussion

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Introduction

• Two paths of the study of consciousness– Search for the neural correlates of consciousness

• Recently, many techniques such as the availability of brain-imaging technique helps this issue burgeoning

– Search for the computational correlates of consciousness• This approach lacks of concrete definitions

• The Purpose of this paper– To delineate a functional aspect of consciousness that

can easily be implemented in a computational progress– To allow for practical experiments, this model of intelli-

gent agents has both formal and executable specifica-tions

• The model is based on Baars’ Global Workspace the-ory of consciousness

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Varieties of consciousness

• N Block, On a confusion about a function of con-sciousness, Behav. Brain Sci. 18(2)(1995)

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Four distinct roles

Category Explanation

Access consciousness(A-consciousness)

- Representative, quantitative, functional- Attached to the sensors reflecting environmen-

tal or self-percepts.- The most inclined to be translate an Algorithm

Phenomenal consciousness(P-consciousness)

- To feel emotional experiences, sensations and to get qualitative inputs- Trickier to implement as it deals mainly with subjective and qualitative information- The hard problems are impossible to solve that rely on subjective aspects(Taylor)(So, it is do not considered it in this model)


• N Block, On a confusion about a function of con-sciousness, Behav. Brain Sci. 18(2)(1995)

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Four distinct roles


Self-consciousness(S-consicousness)

- The reflective capability that we enjoy when we think about ourselves- self-recognition, the awareness of one’s iden-tity- Both cases imply interaction inner states or levels, or between members of a common soci-ety

Monitoring consciousness(M-consciousness)

- The state or process of awareness that leads to one’s sensations and percepts- Internal scanning, which organizes and clusters information contained in the consciousness, is regarded as the proactive function of the con-sciousness- Treats collected information


• J.K. O’Regan, A.Noe, A sensorimoto account of vision and visual consciousness, Behav. Brain Sci. 24(2001)

– Fitted A-consciousness– The authors insists that P-consciousness does not exist– That it provides an interesting approach to sensing is

good when we identify some computational correlates of consciousness

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Focusing on visual experience


Transitive visual con-sciousness or con-sciousness of

- one’s ability to be aware of a particular aspect of a scene

Visual consciousness in general

- A high-order capacity representing the ability to be-come aware of a feature and to be conscious of as-pects of a scene


• J.G. Tayor, The Race for Conscious, MIT Press, Cam-bridge 1999

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Declarative and non-declarative memory


Declarative memory - contains elements that can be conscious- type1 : episodic and autobiographic memories(often called explicit memory) involving experienced or learned elements that one remember- type2 : semantic memory(implicit memory) repre-sents available elements such as general knowledge but the ways they are experienced or learnt elements that one remembers

Non-declarative memory

- contains ‘only representations, such as skills, of which we have no such awareness’


• J.G. Tayor, The Race for Conscious, MIT Press, Cam-bridge 1999

– Three parts based on declarative and non-declarative memory

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Declarative and non-declarative memory


Passive (or perceptual) consciousness

- Occurs when Situations are experienced in a pas-sive mode without accessing to the self

Active consciousness - Occurs when one thinks hard about a problem, paying less attention to perceptual inputs and auto-biographical recalls, unless they are needed to solve the problem

Self-consciousness - the reflective capacity of consciousness ‘in which you are moved by personal memories or are aware of yourself as the experiencer’


• A.P. Atkinson, M.S.C. Thomas, A. Cleermans, Con-sciousness : mapping the theoretical landscape, Trends Cogn. Sci. 4(10) (2000)

• Effective computational simulation should qualify as a specilized process model

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Process vs. Representation theory and Specialized vs. Non-specialized theory


Process vs. repre-sentation

The process vs. representation dimension opposes mod-els that explain consciousness in terms of specific pro-cesses operating over mental representations, with mod-els that explain consciousness in terms of intrinsic prop-erties of mental representation

Specialized vs. non-specialized

The specialized vs. non-specialized distinction refers to the existence or non-existence of a dedicated machinery for consciousness. In the absence of such dedicated ma-chinery, consciousness could be said to emerge from the ‘collective activity of many components distributed both spatially and functionally across the brain, none of them responsible for consciousness on its own’

The global workspace model

• Well formalized computational model of conscious-ness

• Indentifying and describing the actors that are in-volved in consciousness as well as their interactions, roles and functions

• Made of Modules organized in societies, each having its own functionality and specialization

• Not animated by a government but by its members taken as a whole

• A bottleneck is needed to force the modules either to compete or to collaborate

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• Unconsciousness specialized processors– The basic components– A simple skill, a basic knowledge

• Consciousness or global workspace– A working memory that plays the roles of a bottleneck al-

lowing the system to be regulated– When an unconscious specialized processor is unable to

achieve a given task by itself, it accesses the conscious-ness that will in turn broadcast the needs of the proces-sor to the entire system

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• Coalitions and conscious processes– The unconscious specialized processors that answer the

broadcasted needs form together with the requesting processor a coalition able to achieve a given task

• Contexts– They are the assumptions of the system that restrain ac-

cess to the consciousness and discharge the coalition formation process

– A context is unconscious and is constituted of a set of specialized processors

– Contexts are composite skills– They are organized into a hierarchy where higher the

level wider the scope– It supports a form of psychological evolution, a form of

learning.

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Identifying computational correlates of consciousness

• Two Functions established by the observation of the global workspace

– Consciousness gives to the unconscious processors the opportunity to form a coalition in order to achieve a given task

– The global workspace allow to fix coalitions into contexts, thus automating action selection(learning process which allows to shift deliberation to automation M-conscious-ness)

• Two types of processors– Processors that depict the environment

• A representation of external elements or situational informa-tion(Facts)

– Processors that activate an action• The action itself is not represented• We assume that such an action is automated and represented

within a context(To call for an action is similar to a calling for a context) 14

Identifying computational correlates of consciousness

• Formation of coalitions is called deliberation

• A context is defined as an unconscious and permanent processor coalition

– A context formed by Coalitions compiled

• Contexts can select an action without calling on global workspace

• The representation of the environment is abstracted as we assume that the environmental processors are generated by lower-level system

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A sequence abstract machine

• A set of procedures implementing abstract functions defining a general model of reactive agent with sens-ing

• Basic components

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Symbol Explanation

P A plan

A An action

Conditions do(p,a) Action selelction

Conditions switch(p,p’) Changing plan


• Example– An agent whose goal is to wander in a grid and to suck

dirt when he finds some or to go (or stay) home when room is clean

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• Deliberation can be represented within a tree

• Leaves : the action selection processors• Italic-branches : the processor depicting environment• Nodes : the plan names

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• The abstract machine is defined within the following procedures

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Symbol Explanation

l Agent’s local state

e Environment

p A plan(p0 is the initial plan)

├ The deduction rules where an action selection

Υ Transition functions on the environment


• The Layer for Physical system is abstract• This abstract machine implements the deliberation process via sequential processors

• Recalling that consciousness is made of parallel pro-cessors, that several coalitions can access conscious-ness and that consciousness itself is made of two concurrent levels,i.e., deliberation and context forma-tion, calls for a parallel abstract

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A multithreaded virtual machine

• S-conscious– reflective ability– Internal and formal communication language needed to

achieve duties of higher order

• A concurrent agent language that allows to imple-ment agent conversations with dialogues

This language is provided by Bonzon

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Compiling Dynamic Agent Conversations

• Pierre Bonzon, Compiling Dynamic Agent Conversa-tions KI 2002 : Advances in Artificial Intelligence

• Purpose– For multi-agent systems– To implement abstract logical machine that is defined

purely in sequential terms– To support synchronization of this model

• Basic Symbols

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Symbol Explanation

├ The deduction sign

l The Local state

Compiling Dynamic Agent Conversations

• The Dialog Structure

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Symbol Explanation

| 1. To separate the head and tail list2. To Isolate the guard in a guarded message

|| Metasymbol for representing choices

, Sequence or Conjuction

; Alternative or disjunction


• Dialog consists of branching sequences of messages with end alternatives

• Branching sequences can have an embedded struc-ture

• Each alternative is prefixed with a condition, the guard

• A guard acts like a deamon. The dialogue is blocked until a guard is satisfied

• Unless re-entered with a resume message, dialogs are exited at the end of a sequence

• Actions interleaved with messages can be executed with an execute message

• Subdialogues can be entered with an enter message• New parallel dialogues can be run with a concurrent message

• Synchronization between two dialogues is achieved with the pairs of messages tell/ask for information ex-change and call/return for requests

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• These dialogues are compiled into plans executed on an abstract machine

• Each dialogue is executed in a separated thread

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• A representation of the virtual machine

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• The agent behaviors is defined with plans that are now deduced by the concurrent virtual machine im-plemented with concurrent dialogs

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• In order to initiate context formation, which is the second functional correlate of consciousness along with deliberation, we reflect the agent’s deliberation to a meta level

• The deliberation process is mirrored in a concurrent level that will serve to implement the context forma-tion process

• Reflection achieves the agent’s ability to become con-scious of its deliberation steps

• New dialogue introspect starts a new thread attached on both basic deliberation threads : switch and do

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Implementing computational correlates of consciousness

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• The reflected deliberation progress recording each plans switching with the related condition

• Reflect(switch) stores a switched/3 predicate contain-ing the condition C that triggered the plan switching from P to Q in a dedicated object gw(standing for global workspace)

• The condition is obtained through a request commu-nication act synchronizing the switch dialogue with its reflect dialogue


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• The reflected deliberation progress recording each plans switching with the related condition

• Reflect(switch) stores a switched/3 predicate contain-ing the condition C that triggered the plan switching from P to Q in a dedicated object gw(standing for global workspace)

• The condition is obtained through a request commu-nication act synchronizing the switch dialogue with its reflect dialogue


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• Applying reflection to our example may result in ob-taining the following predicates in the gw object:

• Compilation consists in grouping all conditions having led to select an action and generating a new plan of type ‘context’ ==> do(initial, a)‘context’ is the context formed with all the conditions and their generalized arguments


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• Reflect(do) starts the compilation process initiated by the dialogue trace

• Applying it to our example, the following plans are generated :


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• A new plan is set in the agent’s state through the dia-logue teach that runs at the termination of the get_context procedure

• The dialogue teach simply transmits the plan to a learn dialogue that inserts it in the agent’s local state


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Conclusion

• The key to machine consciousness is to rely on a con-current and multilayered model with explicit interac-tions and synchronization between the threads, as for human consciousness

• The axioms proposed by Aleksander and Dunmmal

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AXIOM Valuation

Depiction axiom interacting with the environment

Imagination ax-iom

It is not enough because this model is predefined. However, this paper consid-ers compiled contexts are ‘imagined el-ements’

Attention axiom Bottleneck is attention

Planning axiom Planning consists in calling the uncon-scious processors leading to a change of state or to an action selection

Emotion axiom It is Not enough. But, context disruption supports it.

Discussion

• The Computational correlates of consciousness 의 모델들의 우수성은 어떻게 평가할 수 있나 ?

• 이 논문에서 배제한 P-consciousness(feeling) 을 고려한다고 가정하면 어떤 방법들이 존재할 수 있나 ?

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Documents

A model of agent consciousness and its implementation Ivan Moura Neurocomputing, 69 (16-18) 2006 pp. 1984-1995