Sperling (1960)
Estimating the Iconic Memory
Capacity: Whole report and
partial report methods
Dr. Timothy Bender
Psychology Department
Missouri State University
901 S. National Avenue
Springfield, MO 65897
Whole Report Method
Sperling (1960) is a classic study of the
characteristics of the iconic memory
(visual sensory memory). One
characteristic of the iconic memory that
Sperling explored was its capacity, or
how much information was available in a
single, brief exposure to a visual
stimulus.
Whole Report Method
At that time, a common method for
studying the capacity of the iconic
memory was the Whole Report Method. In
that method, research participants would
be briefly exposed to a visual stimulus,
then asked to recall as much of the
information as possible.
Whole Report Method
In Sperling’s research, the participants
might see a 2x4 array of letters for 50
milliseconds. They then had to report
what letters they saw and in what
position.
D J W P
B S L M
Whole Report Method
In order for you to get a feel for what that
is like, you will see several slides. Each
slide has a 2x4 array of letters. The first
array will appear for about one second or
1000 milliseconds.
Operating hint: To move to the next slide after each example, be
sure the cursor is near the edge of the screen and is in the shape
of an arrow. If the cursor is near the middle of the screen and is
the shape of the pointing finger, you will repeat that slide.
Whole Report Method
The next array will appear for nearly 500
milliseconds.
Whole Report Method
The next array will appear for nearly 100
milliseconds.
Whole Report Method
Sperling’s participants frequently were
exposed to an array of letters for only 50
milliseconds!
Whole Report Method
Sperling manipulated both the number of
letters in the arrays (experiment one) and
the duration of the arrays (experiment
two). He found that neither the number of
letters nor the duration of the display had
an appreciable effect on the results. In
general, his participants could remember
a maximum of between 4 and 5 letters.
Whole Report Method
Procedure:
• After the next slide, you will see 10 stimuli.
• Each stimulus will start with a slide telling you
to get ready. Click on that slide to see the actual
stimulus.
• Then you will see a + sign in the middle of the
screen. Focus on the + sign.
• The + sign will remain for about 1 second and
will be followed by a 3x4 array of letters.
• The array will last for about 70 milliseconds.
• Then you will be asked to record the letters
from the array.
Whole Report Method
Your job is to write down the letters in
their correct positions as quickly as you
can. It is important that you write down a
letter in every position, even if it feels like
a guess. However, do NOT just write
down all Xs or something like that. Also,
do not focus only on one row. That
actually may reduce your overall score.
Prepare for Stimulus 1
Record your response.
Prepare for Stimulus 2
Record your response.
Prepare for Stimulus 3
Record your response.
Prepare for Stimulus 4
Record your response.
Prepare for Stimulus 5
Record your response.
Prepare for Stimulus 6
Record your response.
Prepare for Stimulus 7
Record your response.
Prepare for Stimulus 8
Record your response.
Prepare for Stimulus 9
Record your response.
Prepare for Stimulus 10
Record your response.
Whole Report Method
Scoring Procedure
• For each array, give yourself one point for
each letter in the correct position.
• Add up your points for all 10 arrays.
• Divide that number by 10 to get your mean
number of letters.
Whole Report Method
1 TPBW
QNRL
GXKJ
2 BFJD
KSWZ
DHMZ
3 KGLC
RBDX
FJNT
4 SJKB
VLNY
BFHD
5 CKMF
JTXW
FPSY
6 LHNG
QCGV
FJPL
7 TLOH
WKRT
DGJK
8 DMPL
FVZP
HLRX
9 MPQK
SDHR
CGSM
10 VNRJ
TMQS
FJLH
Whole Report Method
Sperling (1960) found that his participants
could recall between 4 and 5 of the letters. (If
you did as well, that is great. If you did not, do
not worry about it. His participants also had
more practice than you did and completed the
task as individuals rather than in a classroom.)
Partial Report Method
One problem with the Whole Report Method is
that participants claimed that they saw more
letters than they could remember. Apparently,
in the time it took to write down the first few
letters, the memory for the others was gone.
So, Sperling (experiment 3) developed a
different technique, called the Partial Report
Method.
Partial Report Method
In the Partial Report Technique, the
participants only had to report one row of the
stimuli. They were signaled as to which row of
the array to report. The signal was a tone that
occurred at the offset of the array and the rows
were randomly selected. That way, the
participants could not predict which row would
be required. The number of letters they
recalled from the row was then multiplied by
the number of rows to get their score.
Partial Report Method
The logic behind the Partial Report Method is
clear. If a participant could recall X letters from
any one row, then the participant had available
in memory X x Y letters, where Y is the total
number of rows.
Partial Report Method
You will try this in class. You will see 15
different 3x4 arrays of letters. These will be set
up like the previous demonstration, with the
exception that one of 3 tones will occur at the
offset of each array. A high tone means record
the top row. A medium tone means record the
middle row. A low tone means record the
bottom row. The order of the tones has been
randomly arranged.
Partial Report Method
You will need to listen to the tones a few times
in order to recognize which one is high,
medium, and low.
Move the cursor over this speaker to
hear the high tone.
Move the cursor over this speaker to
hear the medium tone.
Move the cursor over this speaker to
hear the low tone.
Partial Report Method
Procedure
• After the next slide, you will see 15 stimuli.
• Each stimulus will start with a slide telling you
to get ready. Click on that slide to see the actual
stimulus.
• You will then see a + sign in the middle of the
screen. Focus on the + sign.
• The + sign will remain for about 1 second and
will be followed by a 3x4 array of letters.
• The array will last for about 70 milliseconds.
• Then you will hear the tone.
Whole Report Method
Your job is to write down the letters in the
row that corresponds to the tone. Record
the 4 letters in their correct positions as
quickly as you can. It is important that
you write down a letter in every position,
even if it feels like a guess. However, do
NOT just write down all Xs or something
like that. Also, do not try to predict which
row will be cued. That actually may
reduce your overall score.
Get Ready for Stimulus 1
Record your response.
Get Ready for Stimulus 2
Record your response.
Get Ready for Stimulus 3
Record your response.
Get Ready for Stimulus 4
Record your response.
Get Ready for Stimulus 5
Record your response.
Get Ready for Stimulus 6
Record your response.
Get Ready for Stimulus 7
Record your response.
Get Ready for Stimulus 8
Record your response.
Get Ready for Stimulus 9
Record your response.
Get Ready for Stimulus 10
Record your response.
Get Ready for Stimulus 11
Record your response.
Get Ready for Stimulus 12
Record your response.
Get Ready for Stimulus 13
Record your response.
Get Ready for Stimulus 14
Record your response.
Get Ready for Stimulus 15
Record your response.
Partial Report Method
Scoring Procedure
• We will treat the first 5 as practice trials, so
we will only score the last 10.
• For your last 10 trials, give yourself one point
for each letter in the correct position.
• Add up your points for those 10 arrays.
• Multiply that number by 3 because there
were three possible rows.
• Divide that number by 10 to get your mean
number of letters.
Partial Report Method
6
7
8
9
10
KSMZ
DQFP
DRCL
GBTQ
KXLC
11
12
13
14
15
KYLP
KPNC
FTRH
SFQH
MPTS
Partial Report Method
Sperling (1960) found that his participants
could recall between 9 and 10 of the letters, on
the average. (If you did as well, that is great. If
you did not, do not worry about it. His
participants also had more practice than you
did and completed the task as individuals
rather than in a classroom.)
Partial Report Method
Based on Sperling’s research and similar
research by others, it was assumed that we
can access at least 9 letters in a single brief
glance at a visual stimulus. If you break that
into separate bits of information, that is about
40 separate bits of information (Sperling, 1960).
Notice, that is at least 40 bits of information.
We still do not know an upper limit on the
capacity of the iconic memory.
Partial Report Method
The reason we do not know an upper limit on
the capacity of the iconic memory is that the
memory trace disappears so rapidly. Simply
using arrays with more letters does not help
because people start to forget the remaining
letters in a row while they record the first ones.
Imagine trying to remember a row of 5 or 6
letters. There is a strong possibility that by the
time you recorded the first 3 or 4 letters, you
would lose access to any others.
References
Sperling, G. (1960). The information available in
brief visual presentations. Psychological
Monographs: General and applied, 74, 1-29.