Global Workspace Theory and LIDA

---- the role of conscious events in cognitive architectures.

This powerpoint is available for educational use, from: www. bernardbaars.pbwiki.com

Additional pdf articles:

1. Baars & Franklin (2007) Architectural models of conscious/unconscious brain functions: GWT and IDA. Neural Networks.

2. Baars & Frankin, (2003) How conscious experience and working memory interact. Trends in Cognitive Sciences.

3. Baars (2002) The conscious access hypothesis: History and recent evidence. Trends in Cognitive Sciences.

Bernard J. Baars

How can scientists study consciousness?

“The study… of the distribution of consciousness shows it to be exactly such as we might expect in an organ added for the sake of steering a nervous system grown too complex to regulate itself.”

--- W. James, The Principles of Psychology, 1890, p. 141

Global workspace theory and IDA/LIDA - development

1970s 1980s 1990s 2000's

Pandemonium - A parallel distributed architecture for cognition.

• The “demons” are little processors that do specialized tasks.

• The blackboard is a place where they can all interact.

• The supervisor tries to keep them on task.

• The eyes scan one word at a time.

• But where is consciousness? Where is the audience?

• From Lindsay & Norman, Human Information Processing.

From Carl Carpenter, A New Model of Consciousness, Sci & Con Rev.2006.

A theater of consciousness - a useful theoretical metaphor

--- only the bright spot on stage is conscious (consciousness is very limited in capacity)

--- sensory inputs compete for access to the conscious bright spot

--- the "stage" corresponds to Working Memory

--- all other features as unconscious, including long-term memory, the automatic processes of language, and the events going

on backstage

-- the theater metaphor has been

turned into several testable models.

Applying GWT to cognitive functions.

Baars & Gage, 2007.

• Brain correlates:

The "spotlight of selective attention" works with the "broadcasting

of conscious contents."

Spotlight - controlled by prefrontal regions. Broadcasting arrow - from sensory

cortex?

Binocular competition for consciousness - gamma resonance.

(Engel & Singer, 1995)

subliminal processing conscious processing

at threshold

Early visual areas Higher visual areas Prefrontal areas

subliminal

conscious

weak masking

strong masking

Masking strength

time following stimulus onset (ms)

Dehaene's Predictions of the global neuronal workspace model

From Dehaene et al, 2001

Experimental results:

Scheider & Chein - architectural model for automaticity.

Novel task --- Automatic task

Conscious input is also turned into longterm memory traces

--- via hippocampal-neocortical distribution.

oare

Conscious visual input flows freely through the Hippocampal Complex) to be encoded in multiple distributed traces in neocortex. (Traces are unconscious)

This allows neocortex to constantly learn and update itself with novel and significant information.

(Nadel & Moscovitch - Multiple Trace Theory. Figure from M. Moscovitch, personal comm. )

"Episodic memory" = memory for conscious episodesHC = Hippocampal Complex, medial temporal lobe

Conscious episodes Hippocampal Complex

Conscious input is also turned into longterm memory traces

--- via hippocampal-neocortical distribution.

oare

Hippocampal connections to neocortex --- huge distribution.

This allows neocortex to constantly learn and update itself with novel and significant conscious information.

(Nadel & Moscovitch - Multiple Trace Theory. Figure from M. Moscovitch, personal comm. )

"Episodic memory" = memory for conscious episodes

The Hippocampal Complex includes neighboring regions in the medial temporal lobe.

GWT-IDA prediction:

All "active components" of Working Memory involve consciousness

From Baars & Franklin,"Consciousness and Working Memory Interact" Trends in Cognitive Sciences.2003

after Baddeley & Hitch

Notice the open circles for conscious moments needed to trigger distributed WM functions.

Memory:

A GW/IDA account of conscious and unconscious aspects of Working Memory

(Baars & Franklin, 2003, TICS)

The LIDA Cognitive Cycle

Sensory Memory

Perception & Perceptual Memory

Environment

Workspace

Transient Episodic Memory

Declarative Memory

Consciousness

Procedural Memory

Action Execution

Action Selection

Structure-building codelets

How the IDA-GWT Cognitive Cycle might run Working Memory

From Carl Carpenter, A New Model of Consciousnes, Sci & Con Rev.2006.

GWT: theater of consciousness - a useful theoretical metaphor

--- only the bright spot on stage is conscious (because consciousness is very limited in capacity)

--- sensory inputs compete for access to the conscious bright spot; so do output plans;

--- the "theater stage" corresponds to Working Memory;

--- all other parts are unconscious, including longterm memory, the automatic processes of language, and events going on backstage. (The capacity of unconsciousness is

enormous.)

-- the theater metaphor has been

turned into several testable models.

From Carl Carpenter, A New Model of Consciousnes, Sci & Con Rev.2006.

Cognitive Cycle OverviewIncoming Stimulus

Understanding

Attending

Selecting

ExecutingAction

Cognitive Cycle

Stabilizing Points in Time

Time line

Incoming stimulus

Percept sent

Model updated

Winning coalition chosen

Action selectedSelecting

Attending

Understanding

Source of selection must be fixed four times - frozen snapshot

Fix SN Fix WorkPlace fix GW Fix BN

Cognitive Cycle Processing

• Hypothesis— Like IDA’s, human cognitive processing is via an iterating sequence of Cognitive Cycles

• Duration— Each cognitive cycle takes roughly 200 ms with steps 1 through 5 occupying about 80 ms

• Cascading— Several cycles may have parts running simultaneously in parallel

• Seriality— Consciousness maintains serial order and the illusion of continuity

• Start— Cycle may start with action selection instead of perception