Transcript Functional Framework for Cognition

Cognitive Architectures
A Functional Framework
for Cognition
Based on book Cognition, Brain and Consciousness ed. Bernard J. Baars
Janusz A. Starzyk
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It seems that the human mind has first to construct
forms independently before we can find them in
things… Knowledge cannot spring from experience
alone, but only from a comparison of the inventions of
the intellect with observed fact.
Albert Einstein (1949)
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Functional Framework

The functional framework used combines two
classical models of cognition
 Baddeley & Hitch, 1974
 Atkinson & Shiffrin, 1968
Yellow arrows symbolize voluntary (top-down)
and spontaneous (bottom-up) attention.
 Long-term memories, knowledge and skills are
shown in grey boxes at the bottom
 Recent version of Baddeley’s Working Memory
(2002) is in the center

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A functional framework.
Sensory
Input
Bottom up
attentional
capture
Vision
Sensory
buffers
Central
Executive
Top-down
Voluntary
Attention
Action
planning
Response
output
Hearing
Working
Storage
Touch
Verbal
Rehearsal
Stored memories, knowledge & skills:
Perceptual
Memory
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Autobiographical
Memory
Visuospatial
Sketchpad
Learning
& retrieval
Linguistic
& Semantic
Visual
knowledge
Declarative
knowledge
Habits &
Motor skills
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Major Functions of Human Brain
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Working Memory
Working Memory
Bottom up
attentional
capture
Sensory
buffers
Central
Executive
Top-down
Voluntary
Attention
Vision
Action
planning
Response
output
Hearing
Working
Storage
Touch
Verbal
Rehearsal
Stored memories, knowledge & skills:
Perceptual
Memory
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Autobiographical
Memory
Visuospatial
Sketchpad
Learning
& retrieval
Linguistic
& Semantic
Visual
knowledge
Declarative
knowledge
Habits &
Motor skills
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Working Memory
The middle column of boxes are components
of the working memory.
 The central executive is believed to be part of
the prefrontal lobes and has a role similar to
executive of a large company.

 Deals with learning tasks,
 Supervisory control over all voluntary activities

Working storage involves the medial temporal
cortex and prefrontal regions.
 Is dynamic, hence more vulnerable to disruption.
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Working Memory

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The executive part of Working Memory involves the prefrontal lobe.
The verbal part --- such as rehearsing words or numbers silently --involves the speech areas of the cortex (especially the dominant
hemisphere). E.g., Broca and Wernicke's areas.
The visual part --- such as visual imagery to think about how to walk
from one place to another --- seems to involve visual regions.
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Working Memory

Inner senses, verbal rehearsal and visuospatial
sketchpad, interact constantly with the long-term
stores.
 Verbal rehearsal/inner speech is for rehearsing and
memorizing information and commentary on our current
concerns, while vocal tract is inhibited.
– Tied to linguistic and semantic component
 Ability to temporarily hold visual and spatial information
is referred to as Visuospatial sketchpad.
– Also involves abstract and cross-modal (more than one sense)
spatial information

Sensory systems begin as domain specific, but
are interpreted as part of multimodal space.
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Working Memory

Long term stores are for knowledge and
practiced expertise.
 Not conscious once stored, but interact constantly
with active functions.
Parts of system work with others, but can also
compete against some.
 The output components are under frontal
control and are related to voluntary motor
functions, control of skeletal muscles and
some mental functions.

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Working Memory
Hippocampus
plays an important
role in forming
new episodic
memories

Damage to the brain, medial temporal lobe (MTL)
can result in inability to move information
 Cognitive functions are spared, but
 Ability to encode and retrieve new experiences are lost.

Immediate memory is needed to perform all tasks.
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Working Memory
In case of the damage to MTL there is no link from
working memory to stored memories.
 Subsequently these new episodes cannot be
recalled.

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Immediate Memory

Immediate memory is needed even for simple
activities like

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
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
Reading.
Face recognition.
Eating food.
Tying shoes.
It involves sensorymotor coordination to
do cognitive tasks.
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Limited and Large Memory Capacity

Brain is large, but its memory capacity is limited.
 Brain has billions of neurons and involves complex
sensory and motor processes.
 Large long-term memory (LTM).
 Short-term memory (STM) is limited to 7+/-2.
– Efficiency increased by chunking, i.e., condense information.
 Low efficiency during multitasking, difficult to do even 2
conscious tasks.
– Practice can improve efficiency.

Limited functions are associated with conscious
experience and large capacity functions are
generally unconscious.
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Limited and Large Memory Capacity

Dual Task limits
 In dual tasks test, as cognitive demands of one goes up,
the efficiency of the other one goes down.
 Novel problems require much effort, brain makes errors
and tend to do them sequentially.
 When skills refine they may be performed with less
conscious effort.

Some memories are very large.
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 Episodic and biographical memories are estimated at 1
bln bits (Landauer, 1986).
 Semantic and procedural memories are also very large.
 Large language vocabulary with related ideas, sounds
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and written words.
Measuring Working Memory

Working memory is tested
by presenting a number of
visual stimuli for recall
 Test may involve recalling a
one shown before, two slides
ago, three slides ago etc..
 The longer the delay the more
difficult the recall.
 Measured is the recall
accuracy and speed.
 Brain activity increases with
difficult tasks
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The mind’s eye, ear and voice

In 4th century BC Aristotle suggested that visual
images were “faint copies” of the visual sensations
 Recent research confirms the he was right.
 C.W. Perky (1910) showed that people confuse faint
visual pictures with their own mental images.
 Ganis (2004) write that “visual imagery and visual
perception use the same neural machinery”.
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The mind’s eye, ear and voice
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Imagery tasks
 Classic rotation stimuli
– check whether two arbitrary shapes are the same or different
– To answer the question subject mentally rotates one shape to
match the other
 Classic ‘tower’ task
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– Roll color ball from one pocket to another one
– How to transform the upper picture to the lower one
– Subjects use visual imagery but the task is different.
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The mind’s eye, ear and voice

Most people talk to themselves
 Ask a person to tell about his private
monologue
– Or write down an internal speech as it
occurs
 Dell and Sullivan (2004) showed that
internal tongue-twisters create very
similar errors to regular ones
– Try repeating “Peter piper picked a peck
of pickled peppers’ in internal speech as
quickly as possible
– Did you noticed inner pronunciation errors
in spite of not really using your tongue?
 Inner talk is confirmed by functional
brain imaging
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Sensory Functions
A functional framework.
Sensory
Input
Bottom up
attentional
capture
Vision
Sensory
buffers
Central
Executive
Top-down
Voluntary
Attention
Action
planning
Response
output
Hearing
Working
Storage
Touch
Verbal
Rehearsal
Stored memories, knowledge & skills:
Perceptual
Memory
EE141
Autobiographical
Memory
Visuospatial
Sketchpad
Learning
& retrieval
Linguistic
& Semantic
Visual
knowledge
Declarative
knowledge
Habits &
Motor skills
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Sensory functions and sensory memory tend to be in the posterior half of cortex.
Left lateral view
(Left hemisphere)
Medial view
SENSORY
Functions
(Right hemisphere)
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Motor and executive functions.
A functional framework.
Sensory
Input
Bottom up
attentional
capture
Vision
Sensory
buffers
Central
Executive
Top-down
Voluntary
Attention
Action
planning
Response
output
Hearing
Working
Storage
Touch
Verbal
Rehearsal
Stored memories, knowledge & skills:
Perceptual
Memory
EE141
Autobiographical
Memory
Visuospatial
Sketchpad
Learning
& retrieval
Linguistic
& Semantic
Visual
knowledge
Declarative
knowledge
Habits &
Motor skills
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Motor functions and planning are frontal.
Left lateral view
(Left hemisphere)
Medial view
MOTOR
Functions
(Right hemisphere)
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Central Executive

The prefrontal lobes play an important
executive role in the brain.
 They are needed for voluntary control over actions.
 Prefrontal also support emotional processes and
are necessary to control one’s unwanted impulses.

Stroop Color-naming task is used to test for
frontal lobe damage.
 Conflict between reading a word and
and naming its color.

Highly practiced actions (reading) tend to be
automatic, while novel and unpredictable
ones tend to remain under voluntary control.
 Automatic and voluntary control work
hand in hand
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Selective attention
and conscious (reportable) events.
A functional framework.
Sensory
Input
Bottom up
attentional
capture
Vision
Hearing
Sensory
buffers
Central
Executive
Top-down
Voluntary
Attention
Conscious
event
Action
planning
Response
output
Working
Storage
Touch
Verbal
Rehearsal
Stored memories, knowledge & skills:
Perceptual
Memory
EE141
Autobiographical
Memory
Visuospatial
Sketchpad
Learning
& retrieval
Linguistic
& Semantic
Visual
knowledge
Declarative
knowledge
Habits &
Motor skills
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Selective Attention and Conscious
(reportable) Events

Attention improves our ability to perceive
stimuli.
 In the case of executive attention, the executive
regions of the prefrontal lobe shapes perceptual
activity in the posterior half of cortex.

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Conscious events seem to mobilize frontal
and parietal regions of cortex.
Voluntary actions become automatic with
practice and they do not need executive
control.
Brain uses combination of voluntary and
spontaneous control
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Executive (Voluntary) and
Spontaneous Attention


Spontaneous attention to find a target on the left.
Voluntary attention to find a target on the right
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Voluntary Action Control
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Motor hierarchy begins with general goals
The goals are represented in the prefrontal area and
proceed to supplementary and pre-motor regions which
triggers intention to act
The primary cortical motor region (M1) triggers movements
of skeletal muscles.
The brain regions activated
in pushing a button with the
right hand
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A functional framework.
Sensory
Input
Bottom up
attentional
capture
Sensory
buffers
Central
Executive
Top-down
Voluntary
Attention
Vision
Action
planning
Response
output
Hearing
Working
Storage
Touch
Verbal
Rehearsal
Long term Memories
Stored memories, knowledge & skills:
Perceptual
Memory
EE141
Autobiographical
Memory
Visuospatial
Sketchpad
Learning
& retrieval
Linguistic
& Semantic
Visual
knowledge
Declarative
knowledge
Habits &
Motor skills
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Consolidation of Events into LTM
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Long-term Memories
Long-term memory
functions are widely
distributed throughout the
brain by means of long
lasting connections.
Posterior half of cortex involves
perceptual regions, while
executive and motor memory,
such as plans for future actions,
engage frontal regions.
Hippocampus is involved with
episodic memory, while subcortical
basal ganglia and cerebellum are
responsible for motor learning.
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Summary
We discussed broad concepts for cognitive
neuroscience.
 Working memory is a foundation of learning and
cognition.
 Immediate memory seems to depend on medial
temporal lobe including two hippocampi.
 Damage to this regions impairs formulation of
long term memories.
 The rear half of cortex is involved in sensory
processing and in sensory-perceptual memory.
 The front half of cortex is involved with motor and
executive functions and long term memory for
these processes.

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