Sperling (1960)
Estimating the Duration of
Iconic Memory: Delayed cues
in the partial report method
Dr. Timothy Bender
Psychology Department
Missouri State University
901 S. National Avenue
Springfield, MO 65897
Duration
In the fourth experiment in Sperling’s
(1960) classic study of the characteristics
of the iconic memory (visual sensory
memory), he explored how long the
memory trace might last.
He used the Partial Report Method with an
added variable – He manipulated the
timing of the cue.
Duration
In the Partial Report Technique
participants see an array of letters with
two or more rows, but they are signaled
as to which row of the array to report.
Usually, the signal is a tone that occurs at
the offset of the array.
Duration
In his fourth experiment, Sperling
manipulated the timing of the cue. The
timing levels included included
• 100 milliseconds before the onset
• With the offset
• 150 milliseconds after the offset
• 300 milliseconds after the offset
• 500 milliseconds after the offset
Duration
Sperling used both 2x3 arrays and 2x4
arrays. He also presented each different
timing condition in a block of trials.
Furthermore, the participants were
exposed to two practice trials before each
set of arrays. Therefore, the participants
became used to each timing.
Duration
As you might expect, the best
performances were when the cue was just
prior to the appearance of the array. The
participants performed more poorly as
the cued was delayed.
Duration
We will do something similar. You will
see several slides with auditory cues
occurring at different times relative to the
presence of the array. Like Sperling’s
study, in this demo you will get each
timing in blocks. However, the array will
be a 3x4 array and the sequence of the
target rows will be random.
Duration
In the first block, you will see 6 different
3x4 arrays of letters. Approximately 100
milliseconds before the array appears, you
will hear a tone. A high tone means you
should record the top row. A medium tone
means you should record the middle row.
And a low tone means you should record
the bottom row.
Duration
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.
Duration
Procedure
• After the next slide, you will see 6 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.
• The tone will occur about 100 milliseconds
before the array appears.
Duration
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.
Duration
Scoring
• Give yourself one point for each letter in the
correct location for all 6 stimuli.
• Multiply that number by 3, because there were
3 rows possible.
• Divide that number by 6 to get your mean
score.
1 GSBQ
4 VSNF
2 SKBS
5 RPFD
3 CBFW
6 PVXR
Duration
In the second set, you will see 6 different
3x4 arrays of letters. The tone will occur
just as the array disappears from the
screen. A high tone means you should
record the top row. A medium tone means
you should record the middle row. And a
low tone means you should record the
bottom row.
Duration
Procedure
• After the next slide, you will see 6 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.
Duration
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.
Duration
Scoring
• Give yourself one point for each letter in the
correct location for all 6 stimuli.
• Multiply that number by 3, because there were
3 rows possible.
• Divide that number by 6 to get your mean
score.
1 DNWF
4 KHXR
2 BFJZ
5 MYJX
3 FXCJ
6 NZBF
Duration
In the third set, you will see 6 different 3x4
arrays of letters. The tone will occur
approximately 100 milliseconds after the
array disappears from the screen. A high
tone means you should record the top row.
A medium tone means you should record
the middle row. And a low tone means you
should record the bottom row.
Duration
Procedure
• After the next slide, you will see 6 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.
Duration
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.
Duration
Scoring
• Give yourself one point for each letter in the
correct location for all 6 stimuli.
• Multiply that number by 3, because there were
3 rows possible.
• Divide that number by 6 to get your mean
score.
1 GSBP
4 LXGC
2 QTDV
5 JWGB
3 LYBG
6 PZQD
Duration
In the fourth set, you will see 6 different 3x4
arrays of letters. The tone will occur
approximately 300 milliseconds after the
array disappears from the screen. A high
tone means you should record the top row.
A medium tone means you should record
the middle row. And a low tone means you
should record the bottom row.
Duration
Procedure
• After the next slide, you will see 6 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.
Duration
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.
Duration
Scoring
• Give yourself one point for each letter in the
correct location for all 6 stimuli.
• Multiply that number by 3, because there were
3 rows possible.
• Divide that number by 6 to get your mean
score.
1 NWJF
4 ZTFV
2 JVHP
5 NZJG
3 WSVP
6 QCMF
Duration
In class, compare your class scores for
the Pre, Offset, 100 delay, and 300 delay
tasks. If you performed similarly to
Sperling’s participants, you performed
best when the tone occurred just prior to
the array and worst with the 300
millisecond delay.
Duration
The following tables shows how Sperling’s
participants performed with the 3x3 and 3x4
arrays. You should note two things:
1 The performance became worse as the
delay increased.
2 The performance in the 1 second delay
condition was close to what Sperling found in
his first experiment using the Whole Report
Method.
Based on these types
of results, Sperling
felt that the iconic
memory trace was
unavailable after a
second. Other
researchers have
since suggested that
250 to 300
milliseconds is a
good estimate of the
duration of the iconic
memory trace.
References
Sperling, G. (1960). The information available in
brief visual presentations. Psychological
Monographs: General and applied, 74, 1-29.