Question
How is working memory related to
attention?
Working Memory
October 11-13, 2004
History of STM and WM
History of STM and WM
Miller:
First claim: STM is different from LTM
because of cause of forgetting
- Fundamental limit on human short
term memory
- 7 +/- 2
- Measure immediate memory span
- Chunking can increase capacity
Rapid decay in STM
Brown-Peterson Paradigm
Cause of forgetting
• Person hears a consonant trigram (e.g., “DSR”) and
then a 3-digit number (e.g. “523”).
• Task: Count backwards by 3’s from the number,
while trying to remember the letters.
• Experimenter varies the duration of counting.
Initially it was thought to be decay—
different from LTM. Later it was shown that
STM is also subject to interference.
100
There are two types of interference:
proactive and retroactive.
Percent Correct
75
50
25
0
0
3
6
9
12
Retention interval(secs)
15
18
Page 1
Proactive interference
Retroactive Interference
Brown-Peterson paradigm: people are
95% accurate on the first trial, even
with a 30 second delay
Brown-Peterson paradigm: delay has a
much worse impact if the delay is
filled detecting syllables, than
detecting tones amid white noise.
STM vs. LTM
Phonological Code in STM
Second claim: Codes or representations
are different
Acoustic confusion effect
- Words presented visually lead to errors
of sound
But later determined other codes:
- Spatial
- Semantic
Release from Proactive Interference
Transfer from STM to LTM
Serial Position effects
100
This result
indicates that
there is also a
semantic code in
STS
- Remember a list of words
80
Percent correct
B-P paradigm
Professions
60
Meats
Flowers
40
Vegetables
Fruits
20
0
1
2
3
4
5
Trial
Page 2
Serial Position Effects
Serial Position Effects
80%
Recency effect: last words in list are
remembered better
Proportion
Correct
Primacy effect: first words in the list
are remembered better
10%
0
Position in List
30
Serial Position Effects
Serial Position Effects
Recency effect: last few words are still
in STM
Primacy effect: first words are
remembered because they are likely to
have entered LTM
How to test this?
Multi-store (modal) Model
Problems?
Atkinson and Shiffrin
Sensory à STM à LTM
Page 3
Problems…
-
Confounds between codes and
processes
Assumption of serial processing
from STS to LTS
-
-
What did neuropsych show?
-
LTS likely to have influence STS
-
not consistent with neuropsych data
Dissociation between STM and LTM
But, patients with deficits in STM could
still have intact LTM
- Failure on digit span
- Intact LTM for words, etc.
LTM not necessarily related to
rehearsal
Thinking about meaning
Response: Craik and Lockhart
• “Depth”: thinking about meaning, and how
the to-be-remembered material relates to
things that you already know.
Levels of Processing
• Shallow processing: means thinking about
physical characteristics of the stimulus.
–Deep processing: “What does ‘cake’ make you
think of?”
–Shallow processing: “How many letters are in the
word ‘cake’?”
Craik & Tulving (1975)
Level of
Processing
Question
to answer
Sample
“yes”
stimulus
Sample
“no”
stimulus
Structural
Is the word
in capital
letters?
TABLE
table
Phonemic
Does the
word rhyme
with weight?
crate
MARKET
Category
Is the word a
type of fish?
SHARK
heaven
Sentence
“He met a
___ in the
street.
FRIEND
cloud
Results
1
0.75
0.5
0.25
0
Structural Phonemic
Category Sentence
Level of Processing
Page 4
Primary Memory
The Working Memory Model
An activation of processes—not a
structure as in STM
Much of what we know about primary memory
was inspired by a particular model of primary
memory called Working Memory
- Focus on process instead of storage
Phonological
Loop
Similar to Baddeley’s Working Memory
capacity
The Working Memory Model
Central
Executive
Visuospatial
Sketchpad
Phonological Loop
Workspace as well as short-term storage
The phonological loop has two components:
1. Phonological store
-
Store about 2 s of auditory information
Information can enter from environment or
from articulatory control process
2. Articulatory control process
-
Phonological Loop
literally, talking to yourself
Visuospatial sketchpad
Articulatory suppression studies
Storage of visual and spatial information.
Separate “visual” and “spatial”?
Page 5
Central executive
Supervisory Attentional System
Cognitive supervisor and/or scheduler,
integrating information from multiple
sources and making decisions about
strategies to be used on tasks
Norman and Shallice
- Activation of schemas
- Sometimes schemas conflict and need
process of contention scheduling
Double dissociations
New component to WM
Support claim of two sub-components of
working memory
Central Executive
- How to test?
- Normals and human lesion patients
Visuospatial
sketchpad
Episodic Buffer
Episodic Buffer
Phonological
Loop
Other approaches to WM
- Dynamic models
- WM as activated subset of LTS
Influence of LTM on short-term
storage
- Eliminate need for multiple memory
structures?
Hold information integrated across time
and space
- Varying ideas on executive control
- Central executive
- Distributed attention
Page 6