Organization of Working Memory—
Reconciling Two Different Models
Anna Alapatt
Working Memory (WM)

Working memory holds information in a rapidly
accessible and easily updated state

E.g. Getting dressed in the morning

Core cognitive ability—predicts intelligence (IQ &
scholastic achievement)

3-4 slots for most people (Luck & Vogel, 1997).
What is Visual Short Term
Memory (VSTM)?
Fixation
Onset
Encoding
Sample array
100ms
Storage
Delay
Comparison
Test array
900ms
•Previous research has shown that people can
maintain 3 to 4 items in VSTM through change
detection tasks.
Two hypotheses about how WM is
organized

General resource model—no matter what is
being remembered a single common resource
determines memory capacity

Many resource model—there are multiple types
of working memory depending on what type of
information is being stored
WM..Many Resources

Domain specific slots

Baddeley Model—many
resources
Baddeley’s Model of Memory
WM..One Resource

Domain General Slots

Cowan Model
Activated
Portion of
LTM
Focus of attention
Cowan’s Memory Model
General Question

Awh, Barton, Vogel (2007), have suggested there
might be two distinct abilities within visual
working memory: 1) number 2)
precision/resolution

Is it possible one aspect (e.g., number) is domain
general, and the other (e.g., precision) domain
specific?
Current Study—2 aspects of memory
ability

Used motion & color as examples (both processed in
distinct parts of visual cortex)

Reconcile the 2 different models

Predictions:

Cowan’s domain general model may be correct with respect to
number

Baddeley’ domain specific model may be correct with respect to the
precision of the memory representations.
Experimental Design
1 second
1 second
Sample Array
Delay Interval
Time
Until Response
Test Array
The number of motion stimuli that could be stored
was reliably correlated with the number of colors.
5.00
R2 = 0.16
4.50
4.00
color K
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
0.00
1.00
2.00
3.00
4.00
motion recall K
This correlation is consistent with Cowan’s stimulus-general
model of capacity in working memory.
The precision of motion recall did not predict how
many colors could be stored in working memory.
5.00
R2 = 0.07
4.50
4.00
color K
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
0.00
10.00
20.00
30.00
40.00
50.00
60.00
precision of motion recall


These data fall more in line with the hypothesis that color
and motion memory are supported by separate resources.
Supports Baddeley’s model
Discussion

The number of motion patches and the number of
colors stored in working memory were correlated.
This suggests a common resource mediating how many
things can be stored in working memory

The precision of motion memory was not correlated
with the number of colors they could store. This
suggest that number and precision are different aspects
of memory ability, and leaves open the possibility that
Baddeley’s multiple resource model is correct with
respect to the precision of representations in working
memory.
Future Direction

This is all a part of a project to look at many
different stimuli (orientation, motion, etc.) and
see how number and resolution relate across
different types of information processed
Thanks….