Download LESSON 3: THE MODAL MODEL

LESSON 3: THE MODAL MODEL
Primary Memory
• Early History
• Broadbent's Model
– The S-System and the P-System
– Broadbent's three assumptions
– 4th Assumption: Acoustic recoding
(Conrad, 1964; Baddely, 1966; Murray, 1967)
– George Miller
• memory capacity (7 ± 2 items)
• chunking
Primary Memory
• The Brown-Peterson Paradigm
– Peterson & Peterson (1959) experiment:
consonant trigrams and counting backward
• Waugh and Norman's Model
– Waugh & Norman (1965) experiment:
presentation rate vs. number of intervening items
– Interpretation of P & P's (1959) results
– H. A. Simon: amount of information in a chunk
Primary Memory
• Atkinson and Shiffrin's Model
– Three structures
• sensory registers
• short-term store (STS)
• long-term store (LTS)
– Three control processes
▪ rehearsal ▪ coding ▪ retrieval
– Structures and processes work together
• transfer
• retrieval from STS (Sternberg, 1966)
• rehearsal in STS
Serial Position Curve & Modal Model
• Free Recall
• Differences between Free Recall Curve and
Serial Recall Curve
• Modal Model Explanation of Primacy and
Recency Effects
• Modal Model Predictions
– Recall will decline as serial position increases
• Rundus & Atkinson's (1970) rehearsal experiment
– Delayed recall should reduce the recency effect but
not the primacy effect
• Glanzer & Cunitz's (1966) delayed recall experiment
• Dissociations
Problems with the Modal Model
• Long-Term Recency Effect
– Bjork & Whitten (1974)
• continual distractor task
• the ratio rule
– Koppenaal & Glanzer (1990)
• change distractor task for last item
– Neath (1993)
• recency with incidental learning task
• recall impaired for 1st item if novel distractor task
• continually changing distractor task yields recency
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Problems with the Modal Model
• “Logical” Problems
– Categorical representation in sensory
memory?
– Responses are always based on a
combination of STS and LTS
(so, how can one isolate the attributes of each?)
• Levels of Processing
¾LEADS TO SINGLE-STORE MODELS …
The Modal Model
Modal Model
The view that memory consists of a sensory
store, a short-term store, and a long-term store.
Information flows from one store to another, and
is retained through a process of rehearsal.
External Response
Modal Model
Memory Terminology
Type of Information
persistent
sensations
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Theory-Neutral
Term
sensory memory
Theory-Specific Term(s)
iconic memory, echoic
memory, precategorical
acoustic store
information retained immediate
only briefly
memory
short-term store, short-term
memory, primary memory,
working memory
information retained generic memory
indefinitely
long-term store, long-term
memory, secondary memory
personal history
autobiographical
memory
episodic memory
knowledge
generic memory
semantic memory
Modal Model
Chapter 3 -- The Modal Model
I.
I . Primary Memory
Primary Memory
History
-- Broadbent's Model
William James (1890) drew distinction between primary
and secondary memory.
-- The Brown-Peterson Paradigm
PRIMARY MEMORY
-- Waugh & Norman's Model
II.
SECONDARY MEMORY
-- Atkinson & Shiffrin's Dual-Store Model
"Rearward portion of present
space of time"
Genuine past
The Serial Position Curve
Linked to conscious experience
Unconscious
Is not "brought back" -- was
never lost
Must be revived
Retrieval is effortless
Retrieval is effortful
I I I. Problems with the Modal Model
I . Primary Memory
I . Primary Memory
History
History
1950's - 60's idea of short-term memory (STM)
was a combination of James's idea of primary
memory with the computer metaphor of
memory:
STM was viewed as a specialized store for
briefly holding information.
-- limited capacity
Just as a computer memory "forgets" when the
power is turned off, STM forgets when attention
is withdrawn.
Most details were developed by Waugh &
Norman (1965) and Atkinson & Shiffrin (1968).
-- short duration
-- primarily verbal
-- a buffer for temporary information
storage
Result was the modal model -- the dominant
view of memory in modern psychology.
I. Primary Memory
Broadbent's Model
Donald Broadbent (1958):
Provided one of the most influential early
approaches to primary memory.
Described a series of systems through which
information flows.
Information enters the preattentive sensory store
-- the "S-System" [= sensory memory]
It is then filtered and sent to a limited capacity
store -- the "P-System" [= short term memory] -the site of conscious awareness
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I. Primary Memory
Broadbent's Model
For Broadbent:
S-System + P-System = primary memory
For information to remain in primary memory, it
must be rehearsed.
Without rehearsal, the information will fade.
Information passes through primary memory on
its way to more or less permanent storage (i.e.,
secondary memory, or long term memory).
I. Primary Memory
I. Primary Memory
Broadbent's Model
Broadbent's Model
Broadbent made three important assumptions
that were retained in most subsequent
models:
1. Primary and secondary memory involve
separate memory systems.
2. Primary memory has a limited capacity.
3. Information is retained in primary memory
only when it is actively rehearsed.
4th Assumption:
Sensory memory stores information in a form
that is identical to the actual stimulus.
In contrast, primary memory recodes the
information and holds it in a speech-like code.
Early experimental results supported this notion
that the main form of representation in primary
memory is acoustic, or sound-based.
I. Primary Memory
I. Primary Memory
Broadbent's Model
Broadbent's Model
Baddeley (1966):
Conrad (1964):
-- presented subjects with lists of letters
-- similar look & different sound (V & X), or
different look & similar sound (V & C)
-- one group read the letters silently, the
other group heard the letters read aloud
-- RESULTS: regardless of presentation
method, errors were based on acoustic
similarity and not visual similarity
Lists presented for
immediate recall
A. phonologically
similar
B. control
C. semantically
similar
D. control
I. Primary Memory
I. Primary Memory
Broadbent's Model
Baddeley (1966):
Murray (1967):
Results
Tested whether primary memory relies on inner
speech, by using articulatory suppression to
prevent subvocal rehearsal.
similar meanings
had little effect
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Broadbent's Model
similar sounds
resulted in poor
performance
Throughout list item presentation, subjects said
the word "the" aloud.
Suggests that the
dominant code in
primary memory is
acoustic
Here, acoustically similar items were no longer
the most common errors
Accuracy was about 66%.
I. Primary Memory
I. Primary Memory
Broadbent's Model
Broadbent's Model
George Miller (1956):
George Miller (1956):
"The Magical Number Seven, Plus or Minus Two"
Investigated the capacity limits of primary
memory.
1. People are unable to learn to identify a set of
items that vary along only one
dimension if there are more than a few
items (e.g., lines of different lengths).
This paper discussed three main topics:
Absolute Identification:
When items vary along multiple dimensions,
they are easier to discriminate from one
another (e.g., letters of the alphabet)
I. Primary Memory
I. Primary Memory
Broadbent's Model
Broadbent's Model
George Miller (1956):
George Miller (1956):
2. People's memory span seems to be about 7
items.
3. What defines an item?
E.g.:
Measure of memory span: the number of
items that can be repeated immediately, in
order, 50% of the time.
17764619112001
is 14 items ...
Too many to remember!
... unless you recode the list into
chunks of information:
Memory span is typically 7, + or - 2.
1776
90% of adults can remember 5, 6, 7, or 8
items.
461
9/11/2001
I. Primary Memory
Broadbent's Model
H.A. Simon (1974):
Chapter 3 -- The Modal Model
I.
-- Broadbent's Model
Found that the number of chunks that can be
recalled is variable.
-- The Brown-Peterson Paradigm
With an increase of information in a chunk, there
is a decrease in the number of chunks that can
be remembered.
So in our example, more chunks like 9112001
(compared to 461) would reduce the number of
chunks you could remember.
The capacity limit in STM is not constant.
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Primary Memory
-- Waugh & Norman's Model
-- Atkinson & Shiffrin's Dual-Store Model
II.
The Serial Position Curve
I I I. Problems with the Modal Model
I. Primary Memory
The Brown-Peterson Paradigm
Named after Brown (1958) and Peterson &
Peterson (1959)
Experimenter reads a consonant trigram (e.g.,
DBX), and then a three digit number (e.g., 482),
aloud.
Subject must count back by 3's or 4's from the
number for a certain amount of time.
The subject is then asked to recall the three
consonants in order.
I. Primary Memory
The Brown-Peterson Paradigm
Counting backward should prevent rehearsal.
Digits are sufficiently different from the
consonants that they should not interfere.
Peterson & Peterson (1959) varied how long
subjects had to count backwards:
3, 6, 9, 12, 15, and 18 seconds
After only 18 seconds of counting backward,
subjects could recall only about 10% of the
items!
I. Primary Memory
The Brown-Peterson Paradigm
I. Primary Memory
The Brown-Peterson Paradigm
Interpretation: information in STM decays very
rapidly when rehearsal is prevented.
However, more recent evidence suggests that
reduced performance with increased counting
time is due to interference.
Data from a later study by Murdock (1961) that included a replication of Peterson &
Peterson's (1959) result and also measured STM for 1 word and 3 one-syllable words.
I. Primary Memory
Chapter 3 -- The Modal Model
I.
Primary Memory
-- Broadbent's Model
-- The Brown-Peterson Paradigm
-- Waugh & Norman's Model
-- Atkinson & Shiffrin's Dual-Store Model
II.
The Serial Position Curve
I I I. Problems with the Modal Model
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Waugh & Norman's Model
Waugh & Norman (1965) put forward a model
that divided memory into two structures:
primary memory -- a limited capacity structure
secondary memory -- a structure with no
capacity limit
I. Primary Memory
I. Primary Memory
Waugh & Norman's Model
Waugh & Norman's Model
Perceived information enters primary memory.
Some is lost by displacement, as new items
"bump out" existing items.
It should be possible to measure the capacity of
primary memory:
If items are continuously presented to a subject,
at some point primary memory will be full and
new items will displace old ones.
Other information is rehearsed, and thus
remains in primary memory longer.
Rehearsal also causes the information to be
transferred to secondary memory.
Recall can be based on information in primary
memory, secondary memory, or both.
Recall for the displaced items will depend solely
on secondary memory.
But if rehearsal is prevented, the items won't
make it into secondary memory either.
I. Primary Memory
I. Primary Memory
Waugh & Norman's Model
Waugh & Norman's Model
Preventing rehearsal will ensure that items are
not refreshed in primary memory and are not
transferred to secondary memory.
Task: recall the digit that followed the probe in
the list
list
probe
intervening items
4653712845672149
3
12
4365712456721849
8
2
Waugh & Norman (1965):
Instructed subjects not to rehearse
Presented lists of 16 digits (1/sec or 4/sec)
Results:
Then presented a probe digit
Presentation rate had little effect
Number of intervening items
between probe and recall had a big
effect
I. Primary Memory
I. Primary Memory
Waugh & Norman's Model
Waugh & Norman (1965)
16 sec list
4 sec list
Waugh & Norman (1965)
There was a sharp drop in performance at about
3 or 4 intervening items.
The asymptote of the function approached zero
-- after a large number of items, subjects could
not recall the target item at all.
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I. Primary Memory
Waugh & Norman's Model
Waugh & Norman (1965)
Forgetting varied with the number of digits
presented between the probe and the end of the
list, but not with the time between the probe and
the end of the list.
This suggested that forgetting was interference
based rather than time based.
I. Primary Memory
Waugh & Norman's Model
Interpretation of the Peterson & Peterson
(1959) findings:
The distracting activity (counting backwards)
would have displaced the information about the
consonant trigram from primary memory.
A little bit of rehearsal occurred and resulted in
transfer to secondary memory.
The 10% recall after 18 seconds reflects the
secondary memory component in the task.
I. Primary Memory
Chapter 3 -- The Modal Model
I.
Primary Memory
-- Broadbent's Model
-- The Brown-Peterson Paradigm
-- Waugh & Norman's Model
-- Atkinson & Shiffrin's Dual-Store Model
II.
The Serial Position Curve
I I I. Problems with the Modal Model
Atkinson & Shiffrin's Dual-Store Model
Atkinson & Shiffrin's (1968) model was similar to
Waugh & Norman's (1965) model ...
... but it distinguished between structural and
processing components of memory.
The structures are those parts of memory that
don't change.
The processes are flexible and under a person's
control.
I. Primary Memory
Modal Model
Atkinson & Shiffrin's Dual-Store Model
The structures:
1. The sensory registers
-- there is a separate one for each sensory
modality
-- the visual sensory register was based on
Sperling's conception of iconic
memory, and later the auditory sensory
register was based on the conception of
echoic memory
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I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
The structures:
The structures:
2. Short-term store (STS)
3. Long-term store (LTS)
-- similar to Broadbent's P-system
-- unlimited capacity
-- limited capacity
-- permanent (although the information may
be modified or rendered temporarily
irretrievable)
-- short duration
-- acts as a buffer in which information can
be stored temporarily
-- holds all enduring memories (e.g.,
knowledge, personal history, just about
anything that one remembers)
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
The structures:
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
The processes:
All information entering LTS has to go
through STS.
Also, when an item is retrieved from LTS it
again has to enter STS.
Note: information is not really transferred
from one structure to another; rather, it is
copied -- leaving the original item in place.
(Fax analogy)
Atkinson & Shiffrin emphasized the control
processes that manipulate the flow of
information.
This flow was held to be under an individual's
control to a large extent.
Control processes are "selected, constructed,
and used at the option of the subject" and
can be "readily modified or reprogrammed at
the will of the subject."
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
The processes:
1. Rehearsal
-- necessary to preserve information in STS
and to copy it to LTS
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I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
The processes:
2. Coding
-- the type of coding determines what
aspects of the sensory information are
remembered and what other information
will be associated with it.
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
The processes:
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
An example of how the structures and
processes work:
3. Retrieval
-- important for getting from LTS into STS
-- but it's not as simple as it sounds:
How does the retrieval process know what
to look for?
How does it know when to stop
searching? (We obviously don't perform
an exhaustive search every time we
retrieve something from LTS)
You see the word "cow" on the screen and at
the same time hear the word "cow" spoken.
The physical properties of the stimulus are
represented in the sensory registers (shape
of the letters in iconic memory, sound of the
word in echoic memory).
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
An example of how the structures and
processes work:
An example of how the structures and
processes work:
Control processes in each sensory store
determine which portions of the information
get transferred to STS.
E.g., the fact that an uppercase "C" was
presented, or the whole word "cow", or the
color of the word ... or ... the sound of the
word, or the gender of the voice that
presented it, or the background noise that
accompanied the word
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
An example of how the structures and
processes work:
.... Or, coding can also take place -- i.e., the
information can be elaborated.
You could focus on the meaning of the word
"cow" or on an image of a cow. Or you could
think of things associated with cows -- milk,
the sound "moo", etc.
For this elaborative coding, the associates
are copied from LTS to STS -- i.e., retrieval is
required.
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I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
If it was the sound of the word that was
transferred, then the acoustic information that
defines the word "cow" is now transferred to
STS.
Rehearsal now occurs in STS.
Rehearsal can be simple rote -- merely
repeating the sound ....
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
STS can store information in a variety of
codes -- visual, acoustic, verbal, etc.
Both rehearsal and the coding options are
under the control of the subject.
We generally prefer a certain type of coding
for a particular type of stimulus, but there is
also great flexibility.
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Atkinson & Shiffrin assumed that the memory
trace in STS was composed of a
multicomponent array consisting of a number
of pieces of information.
These pieces of information can be accurate
or erroneous.
The traces decay, but the decay rate can be
affected by control processes.
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Atkinson & Shiffrin focused most on the
auditory-verbal-linguistic (a-v-l) aspects of
STS and LTS, but they acknowledged that
there were other ways of representing
information.
Why the three terms (in "a-v-l")?
It was impossible to determine whether the
verbal stimuli were being processed as
acoustic, articulatory, or linguistic.
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Transfer
Transfer
Information is transferred (copied) from STS
to LTS via rehearsal.
Important assumption: transfer begins and
continues during the entire time an item is in
STS.
This transfer is an unvarying feature of the
system …
… but the amount and form of the transfer
can be affected by the control processes
used.
The reason for assuming this is the finding
that learning takes place even when the
subject is not trying to remember the
material.
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
How the structures and processes work:
Transfer
Transfer
E.g., Hebb (1961):
E.g., Hebb (1961):
Presented 9-item lists of the digits 1-9 in
random order.
Found that subjects were more successful at
remembering the 9-digit series that had been
repeated -- even though they were unaware
of the repetition.
Most of the lists contained novel orderings,
but one particular list was repeated every
third trial.
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I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
I. Primary Memory
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Transfer
E.g., Hebb (1961):
The amount of transfer can vary with the task
-- several repetitions required in this case to
make a difference in performance
Hebb, 1961
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Transfer
Retrieval from STS
E.g., Hebb (1961):
STS has two main control processes:
rehearsal and retrieval.
The transfer process results in multiple
copies of the original item, each of which
might be incomplete (partial trace)
Atkinson & Shiffrin emphasized the highly
specialized nature of retrieval from STS.
Because of decay, retrieval must be fast and
highly efficient.
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
How the structures and processes work:
Retrieval from STS
Retrieval from STS
Sternberg (1966):
Sternberg (1966):
Presented subjects with a short list of items
(ranging from 1 - 6 items), and then a test
probe.
positive probe = item was in the list
negative probe = item was not in the list
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I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
test list
probe
2
5
3
8
5
Measured RT to say whether the probe item
did or did not occur in the list.
I. Primary Memory
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Retrieval from STS
Sternberg (1966):
Results
The addition of an extra item in the search
set increased in RT by about 40 ms.
Positive and negative probes produced
equivalent RTs.
Number of Items in the List
I. Primary Memory
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Retrieval from STS
Retrieval from STS
Sternberg's interpretation:
But for a positive probe, this makes less
sense. Why not stop the search as soon as
you've found the probe item in the list?
These results support an exhaustive serial
scanning model -- the probe is compared
with each item in the search set, one at a
time.
For a negative probe, this makes sense:
The probe was not in the list, but you have
to check every list item to determine that.
I. Primary Memory
Maybe to keep retrieval from STS fast, you
need an automatic (ballistic) process.
BUT, maybe a capacity-limited parallel
process (Van Zandt & Townsend, 1993)
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Rehearsal in STS
For the a-v-l part of STS, rehearsal is simply
repetition -- like saying the items over & over.
The buffer is like a bin with a certain number
of slots. When the buffer is full, a new item
knocks out an item that is already there.
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Whether an item enters the rehearsal
buffer is up to the subject, who has
control over the rehearsal process.
I. Primary Memory
Atkinson & Shiffrin's Dual-Store Model
How the structures and processes work:
Chapter 3 -- The Modal Model
I.
Primary Memory
Rehearsal in STS
II.
The Serial Position Curve
What determines which items get bumped?
I I I. Problems with the Modal Model
Two possibilities:
-- duration in STS (oldest item gets
bumped first)
-- random method (an item is randomly
selected to get bumped)
II. The Serial Position Curve
The Serial Position Curve
Free recall
-- a task in which subjects are asked to
remember as many items as possible in any
order
-- contrast with serial recall, in which they are
asked to recall the items in order of
presentation (as in modality effects and suffix
effects experiments)
II. The Serial Position Curve
Murdock (1962):
Memory
Tests
Recall
Cued
II. The Serial Position Curve
free recall experiment
Recognition
lists of items varied in length
(10, 15, or 20 items)
all three list lengths produced a serial
position effect:
Uncued
excellent recall for the last few items
Serial
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FREE
better recall for the first few items
than for the middle items
II. The Serial Position Curve
Serial recall and free recall produce similar
looking curves.
But -Differences between serial recall and free recall:
-- in free recall, the recency effect is more
pronounced than in serial recall (Why?)
-- in free recall, the recency effect can be
seen with both auditory and visual
presentation (Why?)
II. The Serial Position Curve
Rundus and Atkinson (1970):
Told subjects to rehearse out loud
20 common nouns were presented
visually for 5 seconds each
There was a high correlation between
proportion correct and number of
rehearsals for each item (except for the
last few items -- the recency effect)
II. The Serial Position Curve
According to the modal model:
Recency is due to the dumping of items from
STS.
Primacy is due to the extra rehearsal time the
first few items get -- they get enough rehearsal
to have a good chance of being copied into LTS.
Therefore, a strong prediction of the model is
that if the number of rehearsals per item can be
measured, the probability of an item's being
remembered will decline the farther down the list
it is.
II. The Serial Position Curve
So, according to the modal model, the primacy
effect is due to the opportunity for extra
rehearsals, and the recency effect is due to
dumping from STS.
Analysis of output order confirms that the last
items are indeed recalled first.
The modal model predicts that if recall is
delayed, then the primacy effect should remain
but the recency effect should disappear. (Why?)
Early items received the most rehearsals
and were recalled very well -- the primacy
effect
II. The Serial Position Curve
II. The Serial Position Curve
Glanzer & Cunitz (1966) tested this prediction.
Presented 15-item lists to subjects
3 recall conditions:
- immediate free recall
- count backward for 10 seconds first
- count backward for 30 seconds first
Results: the longer subjects had to wait
before recall, the less recency effect they
showed.
Why? All those numbers bumped the last items
out of STS.
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Glanzer & Cunitz (1966)
II. The Serial Position Curve
The modal model accounts for the following
results:
-- the serial position effect occurs
regardless of list length
-- the first items recalled will be the last
few list items, followed by the first few
list items
More evidence for dual stores
• Dissociation – when “a single variable has different
affects on two or more measures.”
• Evidence for separate stores, processes, or
representation.
• Many variables have dissociative effect on the
prerecency & recency portion of serial position curve.
Study time
Post-list distraction
Ant. Amnesia
List Length
Word Frequency
-- items will be rehearsed less and less as
the serial position increases
-- the recency effect, but not the primacy
effect, is abolished if recall is delayed
Chapter 3 -- The Modal Model
Anterograde Amnesia
s
t
y
d
• Baddeley & Warrington
(1970)
• H.M. – removal temporal
lobe and hippocampus
• Little/no LTM!
• Yet – on immediate test,
recency intact
• Also, memory span intact
III. Problems with the Modal Model
Prerecency Recency
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=
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I.
Primary Memory
II.
The Serial Position Curve
I I I. Problems with the Modal Model
III. Problems with the Modal Model
The Long-Term Recency Effect
The Long-Term Recency Effect
Glanzer & Cunitz (1966) added a 30 second
distractor activity after the list presentation, and
eliminated the recency effect.
Bjork & Whitten's finding that there is a recency
effect with the continual distractor task -- even
though all of the items should have been
bumped out of STS -- was a challenge for the
modal model.
Bjork & Whitten (1974) added a distractor
activity after each item in the list, and produced
a recency effect.
Continual distractor task -- subjects are required
to engage in a distractor task between
presented items -- they are distracted from
rehearsing the items
Bjork & Whitten proposed the ratio rule:
¾ the size of the recency effect in free recall is
related to the retention interval (RI) and the
inter-item presentation interval (IPI)
recency = f(IPI / RI)
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III. Problems with the Modal Model
The Long-Term Recency Effect
III. Problems with the Modal Model
The Long-Term Recency Effect
recency = f(IPI / RI)
the ratio rule:
The absolute amount of time in item has to be
remembered is not important.
Instead, the recency effect should be similar
when the ratios are similar.
Recency effects for ratios of 1 sec:1 sec,
1 min:1 min, and 1 hr:1hr should be similar.
III. Problems with the Modal Model
III. Problems with the Modal Model
The Long-Term Recency Effect
The Long-Term Recency Effect
the ratio rule: WHY?
Other manipulations were subsequently shown to cause
the recency effect to either appear or disappear:
TEMPORAL DISTINCTIVENESS
–
Koppenaal & Glanzer (1990)
•
Large RI
Small IPI
–
Neath (1993)
•
•
•
Small RI
Large IPI
–
change distractor task for last item – no
recency
recency with incidental learning task
recall impaired for 1st item if novel
distractor task
continually changing distractor task yields
recency
Tan & Ward (2000) – “functional” serial
position
III. Problems with the Modal Model
The Long-Term Recency Effect
The Modal Model cannot account for all the
findings.
III. Problems with the Modal Model
“Logical” Problems
– Categorical representation in sensory
memory?
– Responses are always based on a
combination of STS and LTS (so, how
can one isolate the attributes of each?)
•Levels of Processing
¾ LEADS TO SINGLE-STORE MODELS
…
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