Lecture5:Memory.DrNaif

Chapter 8

Memory

Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

Three Important Distinctions

• Three stages of memory
– Encoding stage – consists of placing a fact in memory
– Storage stage – when the fact is retained in memory
– Retrieval stage – occurs when the fact is recovered
from storage
– Different stages mediated by different brain structures
– most of the regions activated by encoding are in the
left hemisphere while most of the regions activated
during retrieval are in the right hemisphere



• Three memory stores
– Atkinson-Shiffrin theory
• Sensory information enters sensory store which is large, transient
(lasts only few milliseconds), and the small amount of attended to
information is then transferred to short-term memory
• Short-term memory – information you are conscious of, is readily
accessible, subject to decay (over period of around 20 seconds)
unless rehearsed or undergoes other processing (elaborating), in
which case it will move to long-term memory
• Long-term store – unlimited store of the information generally
available to us. Information enters via processes from short-term
memory, and process of retrieval takes information back to short-
term memory to be used for current task



• Different memories for different kinds of
information
– we may use different long-term memory for storing
facts than we do for retaining skills
– Explicit memory – person consciously recollects
previous event, where recollection happens at
particular time and place
– Implicit memory – person unconsciously remembers
information of various kinds


Sensory Memory
• Sperling’s experiments: the partial-report
experiment

– Iconic memory fades away over about a third of a second

Sensory Memory

• Visible persistence: the temporal integration
experiment


Sensory Memory

• Partial report, visible persistence, and a theory
that integrates them

– Two aspects of iconic memory being measured – the part that
allows information to be extracted and part that was visible –
have different characteristics

– The theory which integrates them proposes that briefly
presented visual stimulus triggers a sensory response, the
amount of information acquired from stimulus is related to area
under sensory-response function, and the visibility of stimulus is
related to the rate at which observer acquires information from
the stimulus

Working Memory
• Working memory
– Alternative term for short-term memory to highlight its
role in thinking rather than simply a storage space
• Encoding
– To encode information into working memory, must
attend to it
– Phonological coding – favours phonological code
(sounds of words/digits) to encode information when
keeping it active through rehearsal
– Visual coding – can use visual code for verbal items
but more important for non-verbal items

Working Memory

• Current conceptions of working memory
– Working memory conceptualized as being divided into:
• Phonological loop – for storing & operating on information in an
acoustic code
• Visual-spatial sketchpad – holds & operates visual/spatial
information
• Mediated by different brain structures – phonological loop by
the left hemisphere & visual-spatial sketchpad by the right
• Two systems controlled by the executive – directs attention &
decides what operations performed on the information
• Additional component – episodic buffer which binds or
associates different aspects of a memory


Working Memory

• Storage
– Capacity of working memory limited – for the
phonological loop, memory span is seven items, give
or take two (7 ± 2)
– Chunking – can use long-term memory to perform
chunking – recoding new material into larger, more
meaningful units & storing those in working memory
– Forgetting – occurs either because the items “decay”
over time or are displaced by new items


Working Memory

Retrieval
The more items in working
memory, the slower retrieval
becomes


Working Memory

• Working memory and thought
– When consciously problem-solving, we often use
working memory to store parts of the problem as well as
relevant information accessed from long-term memory
• Transfer from working memory to long-term
memory
– Rehearsal – process of conscious repetition of
information which maintains an item in working memory
(maintenance rehearsal) but can also cause it to be
transferred to long-term memory (elaborative rehearsal)

Working Memory

• Division of brain labor between working memory
and long-term memory
– Working memory and long-term memory
implemented by different brain structures
• Hippocampus – critical for long-term memory
• Regions of frontal cortex – involved in working memory


Long-Term Memory

• Long-term memory
– Involved in storing information from a few minutes to
as long as a lifetime
• Encoding
– Encoding meaning – meaning is the dominant way of
representing verbal material in long-term memory
– Adding meaningful connections – memory can be
improved by creating real or artificial links between
items, e.g. by elaborating on the meaning of material
while encoding it

Long-Term Memory

• Retrieval – poor memory often reflects retrieval failure
rather than storage failure
– Evidence for retrieval failures – unable to recall fact or experience
but recall it later or “tip-of-the-tongue”
– Interference – related information interferes with retrieval process
of target memory. Interference is a major reason why forgetting
from long-term memory increases with time as relevant retrieval
cues become overloaded
– Models of retrieval – some based on the search process whereas
others based on the activation process


Long-Term Memory

• Forgetting: loss of information from storage
– Some forgetting due to retrieval failures but some
information almost certainly forgotten
• Research suggests a function of the hippocampus is to
consolidate relatively new memories
• Interactions between encoding and retrieval
– Organization – more we organize material, easier it is
to retrieve it
– Context – easier to retrieve particular fact/episode if in
the same context as when you encoded it


Long-Term Memory
• Emotional factors in forgetting
– Emotion can influence long-term memory in five ways
• Rehearsal: we think about emotionally-charged situations more
than neutral ones
• Flashbulb memories: vivid & relatively permanent record of
circumstances where one learned of a significant event (e.g.
9/11)
• Retrieval interference via anxiety – anxiety causes/associated
with extraneous thoughts which interfere with memory retrieval
• Context effects – recall best when dominant emotion during
retrieval matches that during encoding
• Repression – ultimate retrieval failure – access to target
memories actively blocked


Implicit Memory
• Implicit memory
– Explicit memory – a matter of consciously recollecting the
past whereas implicit memory is often shown in skills &
involves improvement in perceptual, motor, or cognitive
task without conscious recollection
• Memory in amnesia
– Much of what is known about implicit memory is learned
from people with amnesia (partial loss of memory)
• Anterograde amnesia – inability to acquire new factual information
• Retrograde amnesia – inability to remember events which
occurred prior to injury or disease


Implicit Memory
• ...Memory in amnesia
– Skills and priming – not all kinds of memory disrupted
• Amnesiacs have no difficulty remembering & learning
perceptual and motor skills (explicit & implicit memory different
systems)
• Prior exposure to stimulus facilitates (primes) later processing
of that stimulus – amnesiacs have no difficulty here
– Childhood amnesia – few can recall events from first
years of life
• Probably related to the massive difference in how young
children encode experience & how adults organise memories
• Language development & maturation of hippocampus also
likely to be factors

Implicit Memory

• A variety of memory systems
– Explicit & implicit memory come in various forms
• Implicit memory – perceptual-motor skills & priming involve
different memory stores (based on brain damage research)
• Explicit memory – two kinds – episodic (personal episodes)
and semantic (general truths)
• Implicit memory in normal individuals
– Research again suggests separate systems
• Brain-scanning studies show explicit memory accompanied
by increased neural activity in certain regions while implicit
memory accompanied by decrease in neural activity in
critical regions

Constructive Memory

• Constructive Memory
– Memory is constructive & reconstructive process –
memory for an event can, and does, depart
systematically from the objective reality that gave rise
to it at time of formation and later
• Constructive processes at the time of memory
encoding
– Construction of a false memory can occur at either
initial perception or during transfer from short-term to
long-term memory (or both)

Constructive Memory

• ...Constructive processes at the time of memory
encoding
– Constructive perception – if what is originally perceived
differs from objective world through perceptual errors,
the initial & subsequent memories will be distorted
– Generation of inferences – during transfer from short-
term to long-term memory can draw inferences about
information which is then stored with information – it is
hard to then recall what the original information was
and what was the inference


Constructive Memory

• Post-event memory reconstruction
– Every time we revisit memory it changes in some fashion
– Internally generated inferences – people make inferences
which they incorporate into their memory, e.g. using
schemas, stereotypes etc.
– Externally provided suggestions – information provided
by others may be incorporated into memory, e.g.
suggestive information – can not only distort memories
but can create entirely fictional memories


Constructive Memory

• Constructive memory & the legal system
– Constructive memory particularly important in legal
system due to importance of witness testimony
– Confidence and accuracy
• High confidence is normally predictive of high accuracy in
memory except when circumstances are poor, e.g. an
original event causes poor encoding, post-event
reconstruction takes place or where there is motivation &
opportunity to rehearse reconstructed memory


Constructive Memory

• ...Constructive memory & the legal system
– Suggestive information and children’s memories
• Young children particularly susceptible to suggestive
information, especially during interviews
– Forced confessions
• Interrogation techniques are able to produce genuinely false
memories (& confessions) of crimes that suspects can be
objectively shown not to have committed e.g. by being told
there is evidence, that they were drunk/impaired, that they
have “repressed” memory of crime or told they were suffering
from a personality disorder


Constructive Memory

• Memory errors and normal memory
– Memory illusions – occur when people confidently
“remember” events that never occurred
• Source monitoring – attributing information in memory to its
source. Because it is based on inferences, it sometimes fails
which helps explain some memory illusions, e.g. people may
misattribute the source of post-event information for the
event itself


Improving Memory
Chunking &
memory span

For most capacity of
working memory =
7 ± 2 but can
increase size of
chunk & so increase
number of items in
memory span


Improving Memory

• Imagery & encoding
– Imagery is particularly useful for connecting unrelated
items at the time of encoding & therefore is used in
systems for aiding memory, e.g. mnemonic system, &
key-word method for learning foreign words
• Elaboration & encoding
– The more we elaborate items, the more we can
subsequently recall or recognise them – more
connections, greater the retrieval possibilities


Improving Memory

• Context & retrieval
– Context serves as a cue for retrieval – if it cannot
physically return then can re-create context mentally
• Organization
– Organization during encoding improves subsequent
retrieval – we are capable of storing & retrieving huge
amount of information if we organize it appropriately,
with hierarchical organization preferable


Improving Memory
• Practising retrieval
– Another way to improve retrieval is practice, e.g.
asking yourself questions about what you are learning


Lecture5:Memory.DrNaif

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