Chapter 8: Memory
● memory – cognitive process of encoding, storing and retrieving information
● encoding – process by which sensory information is converted into a form that
can be used by brain's memory system
● storage – process of maintaining information in memory
● retrieval – active process of locating and using stored information
● literal – physiological changes that occur when something is learned
● metaphorical – conceptual information processing models of memory
● learning – tendency for behaviour to change as result of experience, with
performance reflects brain's plasticity
● three forms of memory: sensory memory, short-term memory, and long-term
memory
● sensory memory – memory in which representations of physical features of
stimulus are stored for very brief duration; held long enough to become part of
short-term memory, no analysis takes place but longer than perception
● short-term memory – immediate memory for stimuli that have just been
perceived; limited in capacity (7 + or – 2 chunks of information) and duration
(less than 20 seconds)
● long-term memory – memory in which information is represented on
permanent or near-permanent basis; durable, no limits
Standing – showed people 10,000 colour slides and found they could
recognize them weeks later
occurs due to physical changes that take place in brain
● “modal model” of memory - general conception of memory system
Sensory Memory
● not aware – only when presented briefly
● have sensory memory for every modality – 2 main: iconic (visual) and echoic
(auditory)
Iconic Memory
● iconic memory – sensory memory that holds brief visual image of scene that
has just been perceived; also known as visible persistence
● Sperling – presented visual images through tachistoscope at rate of 9 letters
on screen for 50 milliseconds
on average, person could remember 4 or 5 but insisted that for brief time
could see more but images faded to fast to see all
also used partial report procedure to determine whether capacity of iconic
memory accounted for this limitation
■ asked people to name letters in only one horizontal row indicated by a
tone after letters disappeared
■ able to repeat letters with perfect accuracy – iconic memory had capacity
for all 9
if delay of tone was longer than 1 second people could onyl relay 50%
could not recall all 9 because had faded from memory
Echoic Memory
● echoic memory – sensory memory for sounds that have just been perceived
● necessary for comprehending sound, particularly those that constitute speech – cannot identify word until we have heard whole sound so accoustical
information must be stored temporarliy until all sounds have been received
● evidence from partial reporting shows that it lasts less than 4 seconds
Short-Term or Working Memory
Encoding of Information: Interaction with Long-Term Memory
● information can enter st memory from sensory of lt memory
● working memory – memory for new information and information retrieved
from long-term memory; same as st memory
represents behaviour that takes place inside our head – represents our
ability to remember what we have just perceived and to think about it in
terms of what we already know
Primacy and Recency Effects
● free-recall task – remember what you can of information that was just given to
you
● primacy effect – tendency to remember initial information due to opportunity
for rehearsal which causes them to be stored in lt memory
● recency effect – tendency to remember later information due to fact that
they are last to be rehearsed so are still in st memory
pointed out by Atkinson and Shiffrin
Limits of Working Memory
● Llyod and Margaret Peterson – presented people with stimuli composed of
3 consonants: JRG
people recalled info 30 seconds later
when made to count backwards from 3-4 digit numbers consonants were
only accesible for a few seconds and dropped to zero after 15-18 seconds
● stimuli remain in st memory for 20 seconds unless rehearsed
● Miller – the magical number 7 plus or minu 2: people can retain on average
7+or- 2 pieces of information
chunking – process by which information is simplified by rules, which make
it easily remembered once rules are learned
● can remember more if information can be organized into more meaningful
sequence
● McNamara and Scott – taught people to chain unrelated words together as
they listened to them – imagined story involving those words
Varieties of Working Memory
● Phonological Working Memory:
● phonological short-term memory – short term memory for verbal
information (whether presented visually or accoustically)
● Conrad – showed how quickly visually presented information becomes
encoded acoustically
briefly showed people lists of 6 letters and then asked them to write letters
saw letters visually but when made errors, they were accoustical (V vs. B)
shows that words were encoded acoustically
● phonological memory may be produced by activity in auditory system by
circuits of neurons in auditory association cortex
● subvocal articulation – unvoiced speech utterance
● although no actual movement may occur, is possible activity occurs in neural circuits that control speech
● when we invision something in our minds It is caused by activity in neurons in
visual association cortex
● voice in head is probably from activity of neurons in motor association cortex
● Conrad – attempted to determine whether subvocal articulation played role in
phonological working memory
study on deaf children (could not confuse letters because of their sounds)
children who made accoustical errors were ones who were rated as best
speakers by teachers
deaf children who could speak best encoded letters in terms of movements
they would make to pronounce them
clear evidence for articulatory code in working memory
● people may use acoustical and articulatory coding – simulatenously say word
and feel themselves say it in head
● phonological code stored in lt memory also might help to strengthen rehearsed
information
● conduction aphasia is best evidence for existence of phonoligcal st memory
● conduction aphasia – inability to remember words that are heard, although
they usually can be understood and responded to appropriately; caused by
damage to the connection between Wernicke's and Broca's - deficit in
phonological working memory; might disrupt acoustical st memory by making
such subvocal verbal rehearsal difficult or impossible
● Visual Working Memory:
● possess working memory that contains visual information either obtained from
immediate environment by means of sense organs or retrieved from lt memory
● does not encode all details – find prototype in lt memory
● DeGroot – showed chessboards to expert players and to novices and if
position of pieces represented game in progress, experts could glance at board
for a few seconds and then look away and report position of each piece but
novices could not; experts could also recognize immediately if positions were
placed haphazardly
st memories for positions depended on organizational rules stored in lt
memory as result of years of chess playing
● Gzowski – found similar pattern in Gretzsky's hockey playing
● have ability to manipulate visual information in working memory
● Shepard and Metzler – presented people with pairs of drawings that could be
perceived as 3D constructions of cubes and found people could accurately
judge if pairs were same shape even if rotated; were able to do so in head and
ones that were more rotated, took longer to judge
● Loss of Information from ST Memory:
● st memory information controls behaviour and changes lt memory
● can decay but rehearsal refreshes it – but mostly due to displacement
● Waugh and Norman – heard lists of 16 digits where last digit was
accompanied by tone and called probe digit – when people heard it they had to
think back to last occurence of same digit that tell which digit followed that
one; distance between target and probe was 1-12 items
critical variable was number of items, not time that elapsed – shows that
new information displaces old information in st memory also showed decayed if slow and a lot of digits were in between – but less of
an effect
● St memory is encoded according to previously learned rules and information in
LT memory determines nature of encoding
Learnend Encoding in Long Term Memory
● perceptual memories involve alterations in circuits of neurons in sensory
association cortex of brain, visual memories in visual association cortex,
auditory in auditory association cortex, motor memories in motor association
cortex in frontal lobes
● memories that involve combinations of perceptual information involve
establishment of different connections between different regions of association
cortex
● learning to perform particular behaviour involves establishing connections
between appropriate regions of sensory and motor cortexes
● memory – inovles active and passive processes
The Consolidation Hypothesis
● traditional view of memory is that it consists of 2 stage process: consolidation
● consolidation – process by which information in st memory is transferred to lt
memory, presumably because of physical changes that occur in neurons in
brain
● st memory consists of activity of neurons that encodes information received
from sense organs and once acitibity subsides information is forgotten but
through rehearsal activity can be sustained and if enough time passes activity
causes structural change – permanent and solid; responsible for lt memory
● best evidence for this comes from events that dirsupt brain functioning
● retrograde amnesia – loss of ability to retrieve memories of one's past,
particularly episodic or autobiographical, that occured just before episode
“closed-head injury” - brain bumps on inside of skull
● hypothesis assertions:
st and lt memory are physiologically different
all information gets into lt only after passing through st
most important factor determinig whether paritcular piece of information
reaches lt memory is amount of time it spends in st memory
The Levels of Processing Hypothesis
● Craik and Lockhart – pointed out that act of rehearsal may effectively keep
information in st memory but does not necessarily result in establishment of lt
memories
suggested that people engage in 2 types of rehearsal: maintenace rehearsal
and elaborative rehearsal
● maintenance rehearsal – rote repetition of verbal information; repeating a
given item over and over again; serves to maintain information in st memory
but not necessarily resulting in lasting changes
● elaborate rehearsal – preocessing information on meaningful level, such as
forming associations, attending to meaning of material, thinking about it, etc.
● Craik and Tulving – demonstrated effectiveness of elaboration in
remembering by giving people set of cards containing printed sequence
including missing words denoted by blank line and found that participants were twice as likely to remember sentence if word was of medium or high
complexity
suggest that memory is more effectively established if item is presented in
rich contex
● Craik and Lockhart – proposed framework for understanding process by
which information enters lt memory: suggest that memory is by-product of
perceptual analysis
central processor can analyze sensory information on several different
levels that are hierarchically arranged from shallow (superficial) to deep
(complex)
person can control level of analysis by paying attention to different features
of stimulus
● shallow processing – analysis of superficial characteristics of stimulus, such
as size or shape; example of this processing is maintenance rehearsal
● deep processing – analysis of complex characteristics of stimulus, such as its
meaning or relationship to other stimuli (semantic features); example of this
process is elaborative rehearsal – leads to better retention
Knowledge, Encoding, and Learning
● how we encode information affects our ability to remember it later – paying
attention to it and making it meaningful
● Automatic vs Effortful Processing:
effortful processing - practicing or rehearsing information (deep or
shallow)
automatic processing – formation of memories of events and experiences
with little or no attention or effort
■ information that is automatically processed includes frequency, time and
place
● Encoding Specificity:
encoding specificity – principle that how we encode information
determines our ability to reitve it later
Dooling and Lachman – found that people who were told title of hard to
read passages remembered information much better than if they heard it
after
time to make information meaningful is during encoding
Criticism of Levels of Processing Hypothesis:
● term depth is metaphor, no defined distinction between shallow and deep
processing
● research cannot control depth to which person processes information
● can retain information that relates to shallow processing – answer to question
on page of notes written
Improving Long-Term Memory through Mnemonics
● mnemonic systems – special technique or stratgey consciously employed in
an attempt to improve memory
● Method of Loci:
method of loci – mnemonic system where items to be remembered are
mentally associated with specific physical locations or landmarks
● Peg-Word Method: peg-word method – mnemonic system in which items to be remembered
are associated with set of mental pegs that one already has in memory,
such as key words of a rhyme
● Narrative Stories and Songs:
narrative – mnemonic system in which items to be remembered are linked
together by a story
Bower and Clark – showed people were able to remeber 120 words when
told how to create story from them
Wallace – found people who learned words to sung ballad, rather than
spoken, much more quickly
Kilgour, Jakobson and Cuddy – found that rate of words affected ability
to remember, not whether sung or not
song slows rate so you can remember it better
The Organization of Long-Term Memory
● consolidation is not a simple, passive process – many investigators believe that
lt memory consists of more than pool of information – see it as organized into
different systems where different kinds of information are encoded differently
and stored in different ways, in response to evolutionary pressure
Episodic and Semantic Memory
● lt memory contains more than exact records of sensory information that has
been perceived – also contains information that has been transformed and
organized in terms of meaning
● Sachs – showed that as memory of verbal material gets older, specific sensory
information becomes less important that specific words
had people read passage and then say whether sentence (comparison
sentence) was same sentence (test sentence) – as more syllables passed
people could not remember specific words and sentences but did not get
meaning wrong
form dissapea
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