1 - CSU, Chico

Report
Human Cognitive
Architecture & Working
Memory
Psych 605 Advanced Human Learning
Neil H. Schwartz, Ph.D.
The Metaphorical Model of HCA
Cognition
Environment
Encoding
Control
Processes
Sensory
Register
Short-Term
Store
Retrieval
Long-Term
Store
What do we know about the model?
Original Conceptions
Broadbent (1958) conceived the model.
Concerned with how we attend and retain.
A “pipeline” model: E  SR  STS  LTS
Components of the model are separate, such that variables effect memory in some
stores and not others.
Information is held in an unlimited capacity SR, with some selected for further
coding.
This further coded information is held in a limited-capacity STS.
Then, the coded information is filed in a permanent LTS composed of prior
knowledge that is generally organized.
Atkinson & Shiffrin (1968) refined Broadbent’s (1958) model. They added:
Control processes manage the transfer of information between stores.
Management of the control processes are voluntary and effortful.
The control processes operate to:
Switch attention to selected information for processing
Maintain relevant information in STS
Retrieve information from LTS into STS.
Problems with the Model
The model is now seen as obsolete as originally
conceived. (Broadbent, 1984)
Learner is active, not passive.
Processing is not exclusively “bottom-up”, but also “top
down”.
Processing is dynamic, strategic, and flexible.
Processing is not simply additive.
Some processing is sequential, but other processing is
parallel.
There is more interaction between the stores than
originally conceived.
Awareness is not always required for content to be in
the short-term store.
Prior
Knowledge
Sailboat
Curtins
Pattern
Recognition
Feature
Processing
sails & hull ?
fabric & scallops?
Eye
Problems with the Model
It is not clear that, if SR and STS are actually distinct
entities, what constitutes the demarcation.
The STS is not essential for access to LTS.
Timing and order of information flow is not clear.
For Broadbent, SR fades quickly; STS fades slower; LTS is
permanent.
For Shiffren SR is coded using LTS information which forms
a “trace” in STS.
Feature detectors of SR are very quickly “tuned” by prior
knowledge from the LTS
Features and concepts in LTS can be automatically
activated by incoming stimuli (without awareness).
Features and concepts can be held in STS without
awareness.
The Way the Original Model Evolved
Long-Term
Store
STIMULUS
Sensory
Register
STIMULUS
PK
Short-Term
Store
PK
All the action is in…
Short-Term
Store
WORKING MEMORY
Long-Term
Store
2 Models
Sensory
Register
Short-Term
Store
Cowan, 1988
Baddeley & Hitch, 1974
What is the difference between
STS and WM?
A faculty of mind that can
temporarily hold a limited
amount of information in
a very accessible state with
or without awareness.
A concept term derived from
Miller et al. (1960) to stand
for the way memory is used
to plan and carry out
behavior.
A pattern of neural firing
where the firing pattern, or
cell assembly, is active.
The concept was made popular
among researchers by Baddeley
& Hitch (1974) when they
realized that a single module
could not account for all kinds
of temporary memory.
Temporary Storage
Storage & Manipulation
How does WM work?
Principles of the
Embedded Processing Model
Three
faculties
Principle 1: Working memory information derives from faculties that are
hierarchically arranged. These faculties are: (1) LTM, (2) An activated subset of
LTM, (3) A subset of activated memory that is under the light of attention and
awareness.
Different
Processing limits
Principle 2: Each faculty has different processing limits. The focus of attention:
capacity limited. Activated subset of LTM: time limited. These limitations really
show up under non-optimal conditions (e.g. interference between items with similar
features).
Controlled by
voluntary & involuntary
processes
Principle 3: Focus of attention is controlled conjointly by: (1) voluntary processes
and (2) involuntary processes. Voluntary processes are regulated by the central
executive system. Involuntary processes are controlled by the attentional orienting system.
Unchanged stimuli
activate LTM w/o awareness
Principle 4: Unchanged and unimportant physical features of stimuli still activate
some features in LTM, but without awareness.
Awareness influences
processing
Principle 5: Awareness influences processing. In perception, awareness increases the
number of features encoded. In memory, awareness allows new episodic
representations to be available for explicit recall.
Cowan: Embedded Processes Model
Central Executive
(directs attention and controls voluntary processing)
Attention can be directed outward to
stimuli, or inward to long term memories.
Actions
Controlled
a
b
Unchanged Stimuli
Novel Stimuli d
a
b
c
Automatic
d
Dishabituated
Habituated
Activated Memory
(Short-Term Store)
Habituated
Stimuli
Focus of
Attention
c
Voluntarily Attended
No “filter” is needed; physically
unchanged stimuli do not elicit
attention (b & c), with the
possible exception of significant
signals. Unchanged stimuli can
enter the focus of attention
through voluntary means (a).
Long-Term Store
Brief
Sensory
Store
Long-Term storage of some
coded features occurs automatically (b & c). Attentive
processing (a & d) results in
more elaborate encoding–
critical for voluntary
retrieval, episodic storage.
Initial phase of sensory storage lasts only several hundred milliseconds (left).
Second phase is one type of activated memory (above), both sensory
and semantic activation may last some seconds.
Baddeley: Tripartite Model
Long-Term Store
Central Executive
Attention:
focus, divide, switch
Visual and spatial
Perhaps, haptic
and kinesthetic
Visual code
Linguistic code
Binds and holds
Binding multidimensional codes
Binding
Create & Maintain (temporary or durable)
Visuospatial
Sketchpad
Phonological
Loop
Language-based
Speech – heard
& spoken
Also, lip reading
and gestural signs
Perhaps, environmental
sounds and music
Baddeley’s New Model
Central Executive
Articulatory
Episodic Buffer
VSSP
Visual
Color
Shape
Spatial
Haptic?
Tactile
Kinesthetic
Smell?
Taste?
Phonological Loop
Speech
Sign
Lip reading
Music
Environmental
sound
Which model of WM is better?
Working Memory: Cowan vs. Baddeley
Cowan
Short-term memory is derived
from a temporarily activated
subset of information in longterm memory.
This activated subset may
decay as a function of time
unless it is refreshed, although
evidence for decay is tentative
at best.
A subset of the activated
information is the focus of
attention, which appears to be
limited in chunk capacity.
New associations between
activated elements can form
the focus of attention.
Baddeley
Verbal-phonological (VP) and visualspatial (VS) representations are held
separately, managed and
manipulated with the help of
attention-related processes, in the
central executive (CE).
CE was first believed to have a
general temporary memory
component and a system directive
component. Then, the episodic
buffer replaced the memory
component. The CE is reconceived
as the directive (metacognitive)
component.
Some codes are an activated subset
of LTM, some are not.
Complex interactive system
providing an interface between
cognition and action, capable of
handling information in a range of
modalities and stages of processing.
What is Activated LTM?
Maintaining structural representations by dynamic
bindings.
Manipulating the structural representations.
Flexibly reconfiguring the structural representations.
Partially decoupling the structural representations from
LTM.
Controlling LTM retrieval.
Encoding new structures into LTM.
Oberauer, (2010)
Working Memory:
Cowan vs. Baddeley
Memory
Mechanism
Cowan
Baddeley
Short-term Storage
Mechanism
Activated Memory
Phonological Loop/
Visuospatial
Sketchpad
(time-limited by decay)
(temorary hold)
Chunk-based
Mechanism
Focus of Attention
Episodic Buffer
(chunk-capacity limited)
(binding)

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