Sperling (1960)
Mixed Arrays
Dr. Timothy Bender
Psychology Department
Missouri State University
901 S. National Avenue
Springfield, MO 65897
Mixed Arrays
In the sixth experiment in Sperling’s
(1960) classic study of the characteristics
of the iconic memory (visual sensory
memory), he explored what effect the type
of stimulus had on performance under the
Partial Report Method.
Mixed Arrays
Usually, in the Partial Report Technique
participants see an array of letters with
two or more rows. They are provided a
cue as to which row of the array to report.
Usually, the signal is a tone that occurs at
the offset of the array.
Mixed Arrays
In his sixth experiment, Sperling used a
2x4 array of 4 letters and 4 single-digit
numbers. There were two letters and two
numbers in each row.
Participants were tested for their memory
for the top and bottom rows, as well as
their memory for the four numbers and
the four letters.
Mixed Arrays
The purpose of this research was to see if
people could maintain the visual iconic
trace long enough to make categorical
distinctions as well as they make spatial
distinctions. If the participants could
make number versus letter distinctions as
quickly as they could top versus bottom
distinctions, then they should score
equally well on both types of tasks.
Mixed Arrays
In the first part of this demonstration, you
will see 10 different 2x4 arrays of letters
and numbers. As each array disappears,
you will hear a tone. A high tone means you
should record the top row. And a low tone
means you should record the bottom row.
Record both the letters and the numbers in
their correct locations.
Mixed Arrays
You will need to listen to the tones a few times
in order to recognize which one is high and
which is low.
Move the cursor over this speaker to
hear the high tone.
Move the cursor over this speaker to
hear the low tone.
Mixed Arrays
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.
• 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 2x4 array of letters and
numbers.
• The array will last for about 70 milliseconds.
• The tone will occur as the array disappears.
Mixed Arrays
Your job is to write down the letters and
numbers in the row that corresponds to
the tone. Record these in their correct
positions as quickly as you can. It is
important that you write down a letter or
number 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.
Mixed Arrays
Scoring
• Give yourself one point for each letter or
number in the correct location for all 10 stimuli.
• Multiply that number by 2, because there were
2 rows possible.
• Divide that number by 10 to get your mean
score.
1 D58M
6 C8B9
2 S82Z
7 4VY6
3 1GK3
8 H91W
4 72PK
9 1G4D
5 L4K8
10 2H9N
Mixed Arrays
In the second part of this demonstration,
you will see 10 different 2x4 arrays of
letters and numbers. As each array
disappears, you will hear a tone. A high
means you should record all 4 numbers in
their correct positions. A low tone means
you should record all 4 letters in their
correct positions.
Mixed Arrays
You will need to listen to the tones a few times
in order to recognize which one is high and
which is low.
Move the cursor over this speaker to
hear the high tone.
Move the cursor over this speaker to
hear the low tone.
Mixed Arrays
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.
• 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 2x4 array of letters and
numbers.
• The array will last for about 70 milliseconds.
• The tone will occur as the array disappears.
Mixed Arrays
Your job is to write down the 4 letters or
the 4 numbers, depending on the signal.
Record these in their correct positions as
quickly as you can. Write down a letter or
number in every position in which you
think one occurred, even if this feels like
a guess. However, do NOT just write
down all Xs or something like that. Also,
do not try to predict whether you will
report letters or numbers. 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.
Mixed Arrays
Scoring
• Give yourself one point for each letter or number in the
correct location for all 10 stimuli.
• Multiply that number by 2, because there were either
letters or numbers possible.
• Divide that number by 10 to get your mean score.
1 //82
/5/9
4 6/4/
83//
7 //25
/9/1
2 F//N
/CV/
5 /HL/
/R/W
8 /5/3
/12/
3 T//B
/GJ/
6 /WZ/
/K/N
9 /J/P
//MS
10 /8/6
/25/
Mixed Arrays
Compare your class scores for the Rows
task and the Numbers/Letters task. If you
did not perform nearly as well on the
Letters/Numbers task, you are in good
company. For Sperling’s trained
participants, the average score on the
Letters/Numbers task was 4.6. The
average score on the Rows task was 7.5.
Mixed Arrays
Making a categorical distinction in that
short of a period of time is very difficult.
In fact, this type of result has led
researchers to suggest that iconic
memory processing is pre-categorical.
References
Sperling, G. (1960). The information available in
brief visual presentations. Psychological
Monographs: General and applied, 74, 1-29.