How conscious experience and working memory interact Bernard J. Baars and Stan Franklin Soft Computing Laboratory 김 희 택 TRENDS in Cognitive Sciences vol. 7, no. 4, 2003

Motivation Working memory –Active components of classical working memory are conscious –But traditional theory does not account for consciousness in WM Global workspace theory –Consciousness is needed to recruit unconscious specialized networks Conscious experiences involve widespread distribution of focal information –Each component of network carry out detailed working memory functions Intelligent distribution agent (IDA) model –A large scale implementation of Global Workspace theory –Show how the conscious components of working memory can guide unconscious routines –Specifically, two classical working memory tasks Verbal rehearsal and the utilization of a visual image 1

Working Memory Proposed by Baddeley and Hitch –The most influential integrative model of cognition Phonological buffer –Tested by silent rehearsal of numbers or words Visuospatial sketchpad –Using mental images in problem solving Central executive –Voluntary manipulations of WM functions 2

Global Workspace Theory Cognitive architecture with an explicit role for consciousness Minimal assumptions 1.Brain can be viewed as a network of distributed specialized processors 2.Consciousness is associated with a global workspace in the brain A fleeting memory capacity whose contents are distributed to many unconscious specialized processor 3.A global workspace can also integrate many competing and cooperating input processors 4.Some unconscious processors shape conscious contents Such processors work together to shape one conscious events Such set of processors called ‘context’ 5.Motives and emotions can be viewed as goal contexts 6.Executive functions work as hierarchies of goal contexts 3

The IDA – Implementation of GW Theory IDA (Intelligent Distribution Agent) –Autonomous software agent that automates the entire set of tasks The IDA model adopts GW theory –involved perception, several kinds of memory, consciousness, context setting, and action selection –This sequence as the cognitive cycle IDA uses long-term associative memory –Semantic memory and long-term episodic memory Processing in IDA consists of repeated journeys through the cognitive cycle Codelets –Almost all the work in the system is done by codelets –implemented the unconscious processors of GW theory 4

Codelets Almost all the work in the system is done by codelets Implementing the unconscious processors of GW theory –A small piece of code (a little program) –Performs one specialized, simple task Codelets often play the role of demons waiting for a particular type of situation to occur –After the situation has been occur, they acting out their specialized roles 5

The IDA’s Modules 6 IDA’s modules and the source of their mechanisms, and the theories they support

IDA’s Cognitive Cycle Processing in IDA is a continuing iteration of a cycle of activities –Perception, working memory, episodic memory, long-term associative memory, consciousness, action selection and motor activity –Cognition as a continuing stream of cognitive cycles –Only single cognitive cycle can become conscious Several cognitive cycles may be needed for some WM task –especially such as mental rehearsal 7

Perception Unconscious process Sensory stimuli are received and interpreted by perception Early perception –Input arrives through senses –Find features relevant to their specialty activate appropriate nodes in the slipnet Chunk perception –The convergence of streams from different senses and chunking bits of meaning into larger chunks 8

Percept to Preconscious Buffer The percept is stored in preconscious buffers –including data plus the meaning –Visuospatial, phonological, and other kinds of information Correspond to IDA’s working memory 9

Local Associations Using the incoming percept, local associations are automatically retrieved from episodic memory and long-term associative memory 10

Competition for Consciousness Make attention Attention codelets –Whose job is to bring relevant, urgent, or insistent events to consciousness –Gather information, form coalitions and actively compete for access to consciousness –The activation of unsuccessful attention codelets decays rapidly 11

Conscious Broadcast Broadcast content to global workspace –A coalition of codelets carrying content, gains access to the global workspace and its contents broadcast This broadcast is hypothesized to correspond to phenomenal consciousness 12

Recruitment of Resource Relevant behavior codelets respond to the conscious broadcast –The codelets’s variables can be bound from information in the conscious broadcast 13

Setting Goal Context Hierarchy Some responding behavior codelets is selected The selected codelets instantiate an appropriate behavior stream –The instantiated codelets send activation signal to behaviors 14

Action Chosen The behavior net chooses a single behavior and executes it –This choice come from the just instantiated behavior stream or from a previously active stream The choice is affected by several factor –internal motivation –Current situation –External and internal conditions –Relationship between the behaviors 15

Action Taken The execution of a behavior results in the behavior codelets performing their specialized tasks 16

Analysis of Rehearsal in WM (1) Situation: A subject is asked to remember a seven-digit telephone number for thirty seconds The number is presented visually, together with the request to remember 17

Analysis of Rehearsal in WM (2) Input –The input is recognized and stored as a percept in the pre-conscious buffers –include sound, vision and meaning Automatic local associations –Using the percept, local associations are retrieved from episodic and long-term memory Consciousness –An attention codelet, observing the preconscious buffer –The local associations, brings the sounds, visual images and their meaning to consciousness via a broadcast –At each broadcast the contents of consciousness are also stored in episodic memory Task plan –Behavior codelets respond to the conscious broadcast –instantiate an appropriate behavior stream for responding to the input 18

Analysis of Rehearsal in WM (3) Subject says ‘yes’ to the request –A behavior to respond to the experimenter is selected –Its underlying behavior codelets become active and produce a verbal assent Hearing and understanding ‘yes’(perception) –The spoken assent is sensed, understood, and stored as a percept Automatic associations –In this case there is perhaps nothing of relevance except remembered telephone number Conscious rehearsal –An attention codelet observing local association of the number from transient episodic memory –Brings the sound of the assent and its meaning to consciousness via a broadcast along with an image of the telephone number 19

Analysis of Rehearsal in WM (4) Rehearsal plan –Behavior codelets respond to the conscious broadcast, instantiate an appropriate behavior stream for rehearsal Unconscious inner speech –A behavior to rehearse the telephone number is selected –underlying behavior codelets become active and produce an internal verbal image of the telephone number Unconsciousness inner speech perception Local automatic associations –In this case there might be nothing relevant other than the remembered telephone number Consciousness of inner speech –Its contents are stored again in episodic memory 20

Analysis of Rehearsal in WM (5) Rehearsal plan continued Unconsciousness inner speech Repeat until overt response –The process is repeated for thirty seconds Say telephone number –Codlets who produce an overt verbal expression of the telephone number is selected 21

Relationship between WM, GW, and IDA 22

Summary and Conclusion Global Workspace theory suggests that conscious contents recruit widespread unconscious functions IDA implements GW IDA also suggests in great detail how classical working-memory tasks might be accomplished Many more aspects of consciousness and cognition can be modeled with this approach, yielding explicit, testable and detailed predictions 23

E.N.D