Models of Memory January 28

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Models of MemoryJanuary 28
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Todays
Lecture

• Summary of the previous lecture
• The Architecture (Structure) of Memory
• Multi-store models of memory
• Working memory
• 3. Memory Processes

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• Cognitive Psychology in a Nutshell
• The problem in a nutshell why sometimes your
  reaction is guided by understanding the stimulus
  not but the stimulus itself? You cant predict
  behavior focusing only on the stimulus

• Cognitive modeling of the black (mind) box

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Main Paradigm of Cognitive Psychology
Information Processing Approach

• Mind is to brain as program is to computer
• Information can be processed and stored
  (remembered) in the brain, retrieved, changed,
  communicated and turned into action.
• There are rules (logical or otherwise) by which
  information is manipulated or processed.

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Top-down and bottom-up processing

• Bottom up data driven, data-based processing
  most (all) of the required information comes from
  the sense organs
• Top down conceptually driven knowledge-based
  processing most (all of the required information
  comes from the mind

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Disciplines of Cognitive Science
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Four main research methodologies used in modern
Cognitive Psychology

• Experimental cognitive psychology
• Involves carrying out experiments on healthy
  individuals, typically under lab conditions
• Cognitive neuropsychology
• Involves studying patterns of cognitive
  impairment shown by brain-damaged patients to
  provide information about normal human cognition
• Computational cognitive science
• Involves developing computational models
• Cognitive neuroscience
• Involves brain-imaging techniques to study
  aspects of brain functioning and structure
  relevant to human cognition

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Four lobes of the cerebral cortex
Ventral (at the bottom) dorsal (on top)
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Two hemispheres of the brain
Lateral at the side
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Medial section of the brain
Medial in the middle
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Todays
Lecture

• Summary of the previous lecture
• The Architecture of Memory
• Multi-store models of memory
• Working memory
• 3. Memory Processes

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The Architecture of Memory

• Theories of memory generally consider both the
  architecture of the memory system and the
  processes operating within that structure.
• Architecture refers to the way in which the
  memory system is organized, and process refers to
  the activities occurring within the memory
  system.

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Multi-Store Memory Model Modal Model (Atkinson
Shiffrin, 1968)

• There are three types of memory stores

Rehearsal
Attention
Sensory stores
Short-term store
Long-term store
Decay
Displacement
Interference
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Basic Memory Processes

• Retrieval, maintenance, encoding

Attention
Interference, Decay
Decay
Displacement
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Sensory stores

• Sensory memory is the pre-categorical memory
  store that retains purely sensory information
• Holds information very briefly and is
  modality-specific (limited to one sensory
  modality, such as iconic sensory store or echoic
  sensory stores.
• Only this information that is attended and
  processed further buy the short-term memory store
• Information lost is due to decay (400 ms for
  iconic store and 2 sec for the echoic store)

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Sperling (1960) whole report

• An array of letters (three rows of four) was
  flashed briefly (50 millisec)
• In whole report, the observers were asked to
  recall as many letters as possible ( 4).
• Sperling (1960) assumed that this happened
  because visual information had faded before most
  of it could be reported.

B F H K D C J M T R P N
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Sperling (1960) partial report

• An array of letters (three rows of four) was
  flashed briefly (50 millisec)
• In partial report, a high, medium, or low tone,
  presented after the offset of the array,
  indicated that the letters in only the top,
  middle, or bottom row were to be reported.
• If the tone played approximately after 400 ms,
  the subjects were able to report the whole row.

B F H K D C J M T R P N
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Sperling (1960) whole and partial report
http//frank.mtsu.edu/sschmidt/Cognitive/sensory_
store/sensory.htmlVisual

• Sperling concluded that information in iconic
  storage decays within 400 milliseconds.

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Main characteristics of short-term memory store

• Extremely limited capacity Miller and the
  magical number 7. Only about seven chunks (pieces
  of information organized into a larger piece) of
  information can be retained in STS at a time
• I, F, M, B or
• IBM, FBI

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Main characteristics of short-term memory store
(Continued)

• Coding visual and acoustic (the way in which
  information is mentally represented how will
  you try to remember a phone number, visually?
  verbally?)
• Fragility of storage, any distraction usually
  causes forgetting

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• Main characteristics of long-term memory store
• Long-term memory stores a large amounts of
  information for indefinite periods of time
  (treasure chest or scrapbook)

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Main characteristics of long-term memory store

• Indefinite capacity (think about the information
  you have stored in your LTM)
• Retention duration (how long information can be
  stored in LTM? A whole lifetime!)

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Functions of memory stores
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The primacy and recency effects serial position
curve

• A list of 15 words is presented at a rate of one
  word per 3 sec and immediately after the final
  word the participant tried to recall as many of
  the words as possible.
• Spider, dentists, dog RECALL
• Recency effect the last few items are well
  recalled
• Primacy effect the first few items are well
  recalled

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Serial Position Curve (The Primacy and Recency
Effects)
Proportion Correct
1
0
1
15
Serial position
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Serial Position Curve (The Primacy and Recency
Effects)
In one experimental procedure the subject is
required to carry out an arithmetic task 30 sec
immediately following the presentation of the
list. The recency effect was eliminated in this
experiment, while the primacy effect was
unaffected.
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Serial position curve after arithmetic task
Probability Correct
1
0
1
15
Serial position
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Evidence for Multi-store Model

• Double dissociation with brain-damaged patients
  (two tasks involve a different mechanism if some
  patients perform well on task A but poorly on
  task B, while other patients perform well on task
  B but poorly on task A)
• Amnesic patients perform poor on LTM task but
  well on STM, there is also some evidence that
  some patients (KF impaired digit span) perform
  well on LTM but poor on STM. But KF has
  non-impaired visual working memory!

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Evaluation of Modal Model Evidence against

• Too linear and oversimplified evidence that
  information can access LTS before STS.

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Standard Memory Model

• Information in STS is in a state of activation
• Permanent knowledge is activated, as a by-product
  of on-line cognitive processing, and comes to
  reside in STM.
• Thus, STM is simply defined as the collective set
  of this activated information in memory

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• This is the slightly less simple story
  Baddeley Hitch in 1974 suggested a more
  sophisticated model - the working memory model.

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Todays
Lecture

• Summary of the previous lecture
• The Architecture of Memory
• Multi-store models of memory
• Working memory
• 3. Memory Processes

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Working Memory

• Working memory is a system that is used for
  temporary storage and manipulation of information
  and it is involved in many higher cognitive
  functions.
• Working memory involves two short-term storage
  systems (verbal and visual) and executive
  processes (resembling attention) that operate on
  the contents of storage.

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Episodic buffer holds and integrates Diverse
information
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Phonological Loop

• The word-length effect Participants ability to
  reproduce a sequence of words is better with
  short words than with long words
• Participants can produce immediate serial recall
  of as many words as they could read out in 2 sec
  (that is, memory span is determined by the rate
  of rehearsal)

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Phonological Loop

• The model suggests that the limits of short-term
  memory for words and numbers may be set by the
  amount of time it takes to 'say' the words to
  yourself - so the limit is about 2 seconds-worth,
  rather than about 7 chunks.
• Articulatory suppression (repeating digits from 1
  to 8) eliminate word-length effect

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recalled
Visual presentation - no articulatory suppression
90
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Visual presentation - suppression (counting from
1 to 8)
Short words
Long words
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Phonological loop system
Auditory word presentation
Articulatory control processes
Phonological store
Visual word presentation
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Neural correlates of verbal WM

• Studies with brain-damaged patients
  double-dissociation
• JB PV have a damaged phonological store but
  intact articulatory loop (poor STM but normal
  speech production)
• TO has an intact phonological store but a damaged
  articulatory loop shown by a lack of evidence for
  rehearsal

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Neural correlates of verbal WMfRMI study of
Henson et al (2000)
Phonological storage Left inferoir parietal area
Articulatory process Rehearsal (left preforntal
areas)
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The visuo-spatial sketchpad VSSP

• Did you play Memory in your youth?
• Try
• http//www.allthetests.com/tests/flipmatch/puzzle.
  php3
• A fun page about various kinds of memory games
• http//faculty.washington.edu/chudler/chmemory.htm
  l

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The VSSP

• What is the VSSP good for?

The VSSP is a system for setting up and
manipulating visuo-spatial images
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What does VSSP stand for?
Baddeley (1986 109) claims that VSSP originally
stood for visuo-spatial scratchpad and was
later changed into visuo-spatial sketchpad,
suggesting that it deals primarily with visual
shapes and not with verbal notes (as the word
scratchpad suggests). Logie (1998 69, referring
to Baddeley) claims that VSSP originally stood
for visuo-spatial sketchpad and was later
change into visuo-spatial scratch pad. So whose
memory is disrupted here? Fortunately, both
words are used interchangeably in the literature.
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Working Memory Model Assumptions

• If two tasks use the same components, they cannot
  be performed successfully together
• If two tasks use different components, it should
  be possible to perform them together
• Are visual and verbal components independent?

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Visuo-spatial sketchpad (Logie)
Recall ()
Irrelevant Speech
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Irrelevant drawing
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Rote rehearsal
Visual Imagery
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The Brook's 1968 task

• 2 tasks
• 1. Visuo-spatial task (Visual categorization in
  the F-task)
• 2. Verbal task (verbal categorization of nouns
  in a sentence)

2 modes of response Visual Pointing to the two
words YES/NO on a response sheet Verbal saying
Yes and No
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The two tasks

• Spatial task
• F
• Imagine a block capital letter F, start moving
  from the bottom left corner upwards and
  responding
• Yes if the corner belonged to the bottom or top
  line
• No if it didn't
• Y Y Y N N N N N N Y

• Verbal task
• Subjects had to remember a sentence
• A bird in the hand is not in the bush
• Subjects had to classify each word for being a
  Noun or not
• N Y N N Y N N N N Y

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Result Interaction task modality x response
modality

• Performance in the spatial F task dropped if
  the response mode was spatial (pointing)

• Performance in the verbal categorization task
  dropped if the response mode was verbal (speaking)

--gt Processing modality and response modality
draw on the same resources, spatial or verbal and
therefore interfere .
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The Brooks matrix task and visual interference
(visual pursuit tracking)

• Primary task modified memory span procedure
  (Brooks matrix task)
• Subjects received instructions as to where to put
  numbers in a 4x4 matrix
• Subjects had to repeat back experimenter's
  instruction

• Effect of
• Written or oral instruction
• Secondary tasks, e.g. arm movements, visual
  pursuit

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The Brooks matrix task
Spatial condition In starting square put a 1.
In the next square to the right put a 2... --gt
subjets can figure out a spatial path through the
grid Nonsense condition In the starting square
put a 1. In the next square to the quick put a
2... --gt subjects cannot figure out such a path
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Effect of visual pursuit tracking on the Brooks
matrix task

• Control condition
• No secondary task, only memory of the learned
  sentences under spatial or verbal condition
• Experimental condition Effect of secondary
  visuo-spatial task (visual pursuit tracking) only
  on the spatial condition, not on the verbal
  nonsense condition
• --gt This interaction shows again that 2
  concurrent spatial tasks interfere with each
  other, hence they both use the resources of the
  VSSP.

Spatial matrix task
Verbal matrix task
Mean errors per subject
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The VSSP- visual or spatial?

• The pursuit tracking task was spatial in nature.
  In order to find out whether a purely visual
  secondary task would also interfere with a
  visual-spatial primary task, Baddeley conducted a
  similar experiment with the Brooks matrix task as
  the primary task and a concurrent secondary task
  that was either
• Visual judging of the brightness of projections
  or
• Spatial pit-and-the-pendulum task

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VSSP visual or spatial?

• Result spatial task
• The concurrent spatial task disrupted memory in
  the spatial Brooks task

• Result visual task
• The concurrent visual task did not disrupt memory
  in the spatial Brooks task

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Visuo-spatial sketchpad
Logie (1995) suggested that visuo-spatial working
memory could be subdivided into two
components First stores (visual cache)
information about objects appearances (visual
form and color) The second (inner scribe) deals
with spatial and movement information
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Ventral vs. dorsal dissociation
Farah et al (1988) studies with brain-damaged
patients Smith Jonides(1997), Courtney et al
(1996) - neuroimaging
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Central Executive

• Specifically, the central executive resemble an
  attentional system, and it is responsible for
• Switching of plans
• Timesharing in dual-task studies
• Selective attention to certain stimuli when
• ignoring the others
• Temporary activation of long-term memory

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Central Executive

• Central Executive - The central executive
  controls attention and the allocation of
  attention resources (resides in frontal lobes).
  The central executive receives, coordinates, and
  integrates information from slave subsystems
  and long-term memory.

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Central Executive at our frontal lobe
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Central Executive
Correlates with complex IQ tests However, the
role played by central executive remains not
entirely clear. It has limited capacity but it
is hard to measure this capacity
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Central Executive as a coordination or
integration system
A strength of the CE is that it offers the
potential to explain aspects of developmental and
adult skills and what intelligence is The main
weakness of the CE lies in its attempts to be all
things to all tasks
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Episodic Buffer?
There seems to be something messing since none of
the current components can be regarded as a
general storage system that can combine several
kinds of information. Episodic buffer has been
introduced to integrate information from a range
of courses into a single complex structure or
episode.
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(No Transcript)
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Todays
Lecture

• Summary of the previous lecture
• The Architecture of Memory
• Multi-store models of memory
• Working memory
• 3. Memory Processes

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LTM Processes and Structure

• Two main processes Encoding (from STS to STS)
  and retrieval of information (from LTS to STS)

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Forgetting Lost? Or confused?

• Why do we forget?

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What is forgetting?

• We will look at some psychological explanations
  of forgetting
• The inability to retrieve previously available
  information.
• It is useful to think of forgetting as a problem
  of either availability (it was never properly
  encoded and therefore is not available), or
  accessibility (it was encoded but the
  information cannot presently be accessed).

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Theories of forgetting
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Theories of Forgetting

• Poor encoding
• Decay theories
• Interference theories
• Retrieval-cue theories
• Repression- (Freud)
• Damage (e.g. amnesia)

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Forgetting as encoding failure

• Information never encoded into LTM

X
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Encoding Failure

• Where is the number 0 on your calculator?
• What letters accompany number 1 on your mobile
  phone?
• According to this theory, objects seen
  frequently, but info never encoded into LTM

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Factors that Influence Encoding Depth of
processing (Craik Lockhart, 1972)

• The level of depth of processing of a stimulus
  has a large effect on its memorability
• Deeper levels of analysis produce more elaborate,
  longer lasting, and stronger memory traces than
  do shallow levels of analysis
• Maintenance rehearsal involves repeating the
  material while elaborative rehearsal involves
  deeper or more semantic analysis of the learning
  material
• Only elaborative rehearsal improves long-term
  memory and prevent forgetting

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Forgetting as retrieval failure
Not all forgetting is due to encoding
failures Sometimes info IS encoded into LTM, but
we are unable to retrieve it.
X
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Tip of the tongue phenomenon

• a.k.a. TOT experience (Brown McNeill, 1966
  Brown, 1991)
• Cant retrieve information that you absolutely
  know is stored in your LTM
• TOT is a near-universal experience in memory
  recollection involving difficulties retrieving a
  well-known word or familiar name.
• Two key features of TOT are inaccessibility and
  imminence (Brown, 1991)
• Example http//www.missionimpossible.com/
• But who directed it??????
• Evidence of forgetting as an inability to
  retrieve information.
• BUT Why cant we retrieve info?

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Retrieval failure theories

• Decay theories
• Interference theories
• Retrieval cue theories

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Trace Decay Theory

• Biology-based theory
• When new memory formed, it creates a memory trace
• a change in brain structure or chemistry
• If unused, normal brain metabolic processes erode
  memory trace

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Decay theories evidence

• Memories fade away or decay gradually if unused
• Time plays critical role
• Ability to retrieve info declines with time after
  original encoding
• Forgetting curve Ebbinghaus, (1885) very rapid
  over the fist hour and slowing down thereafter

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Decay theories

• Information CAN be remembered decades after
  original learning even if unused since original
  learning (name of old school friend)
• Sleep is believed to play a key role in halting
  trace decay, although the exact mechanism of this
  is unknown
• Decay Theory more applicable to STM

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Interference theories

• Memories interfering with memories
• Forgetting NOT caused by mere passage of time
• Caused by one memory competing with or replacing
  another memory
• Two types of interference

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Two types of interference
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Retroactive interference

• When a NEW memory interferes with remembering OLD
  information
• Example When new phone number interferes with
  ability to remember old phone number.

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Retroactive interference

• Example Learning a new language (Spanish)
  interferes with ability to remember old language
  (French)

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Proactive interference

• Opposite of retroactive interference
• When an OLD memory interferes with remembering
  NEW information
• Example Memories of where you parked your car on
  campus the past week interferes with ability find
  car today

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Proactive interference

• Example Previously learned language interferes
  with ability to remember newly learned language

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Retrieval failure Retrieval cue theories

• What is a Retrieval cue
• a clue, prompt or hint that can help memory
  retrieval
• Forgetting the result of using improper retrieval
  cues

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Recall vs. Recognition tests

• Importance of retrieval cues evident in recall
  vs. recognition tests
• Recall tests - must retrieve information learned
  earlier
• Examples Fill-in-the-blank test essay exams
• Recognition tests - only need to identify the
  correct answer
• Example Multiple choice tests

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What is the capital of Bulgaria?

• Raise your hand if you know the answer

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What is the capital of Bulgaria?

• A. Arbanassi
• B. Sofia
• C. Stockholm
• D. Nessebur
• Raise your hand if you know the answer
• Which was easier recall or recognition?

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Which retrieval cueswork best?

• According to the Encoding specificity principle
  (Tulving, 1974) cues used during initial learning
  more effective during later retrieval than novel
  cues
• In other words, most effective retrieval cues are
  those that were stored along with the memory of
  the experience.

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Which retrieval cues work best?

• Context-dependent memory
• Improved ability to remember if tested in the
  same environment as the initial learning
  environment
• Better recall if tested in classroom where you
  initially learned info than if moved to a new
  classroom
• If learning room smells of chocolate or
  mothballs, people will recall more info if tested
  in room with the same smell
• compared to different smell or no smell at all

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Context dependent effects

• Time of day is also important

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Context-dependent effects

• Words heard underwater are best recalled
  underwater
• Words heard on land are best recalled on land
• Godden Baddeley (1975)

recall
Water/ land
Land/ water
Water/ water
Land/ land
Different contexts for hearing and recall
Same contexts for hearing and recall
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State-dependent effects

• Recall improved if internal physiological or
  emotional state is the same during testing and
  initial encoding
• Context-dependent - external, environmental
  factors
• State-dependent - internal, physiological factors

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State-dependent effects

• Mood or emotions also a factor
• Bipolar depressives
• Info learned in manic state, recall more if
  testing done during manic state
• Info learned in depressed state, recall more if
  testing done during depressed state (Reus
  Weingartner 1979)

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State dependent effects
Performance better if Happy during recall/
Unhappy during learning
Happy during learning
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Consolidation

• Long-term memory (LTM) includes both recent
  information, which can be fragile, and
  information that has been consolidated and in
  store for some time.

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Consolidation

• Consolidation is a process lasting for
  several hours or possible even days which fixes
  information in LTM
• The process of consolidation involves a
  rapidly formed and relative long-lasting increase
  in the probability that postsynaptic neurons in
  the hippocampus will fire in response to
  neurotransmitters released from pre-synaptic
  neurons.
• A key assumption is that recently formed
  memory still being consolidates are especially
  vulnerable to interference and forgetting.
• New memories are clear but fragile and old
  ones are faded but robust
• Dsupports by Aeb curve that the rste of forgettin
  decreases as the length of time after learning
  increases