fractions of a second after the
physical stimulus is no longer there
used for watching a film to make
sense of one still image to the next
short term memory
elements
encoding
the way that sensory input
is represented in STM
factors affecting encoding of STM
sound of words
acoustic is preferred in STM
Brandimonte, 1992
aim
influence of visual
process on encoding
procedure
6 drawings of familiar objects and
asked to removed certain parts
create mental image and
subtract part of it. then rename
findings
could name 2.7 times out of 6
better than those
repeating
meaningless chant
evaluation
lacks eco validity
cant be generalised
for all images
same 6 images
duration
the length of time that
information can be held in STM
factors affecting duration of STM
maintenance rehearsal
deliberate intention to recall
amount of information to be retained
Peterson and Peterson (1959)
aim
to test how long STM lasts
when rehearsal is prevented
procedure
shown a trigram
count backwards in 3s
from specific number
after 3,6,9,12,15 or 18 secs
intervals had to recall
findings
recall 80% of
trigrams after 3 secs
fewer trigrams
as longer time
18 secs less than 10%
conclusion
less items recalled
after longer time
evaluation
trigrams are artificial
don't fully reflect
interferece from previous trigrams after recall not just decay
capacity
the amount of information that can
be stored in STM at any one time
factors affecting capacity of STM
influence of LTM
information stored in the
LTM is helping to increase
STM capacity temporarily
reading aloud
if participant reads the digits aloud before recall,
performance is better than when they simply read
them withoout speaking to themselves
rhythmic grouping
performance improves if the numbers
are grouped together rhythmically
explains why we divide up telephone numbers
pronunciation time
some words are longer
than others
arabic compared to english
Baddeley et al. (1975)
aim
to see if people could remember more short
words than long words in a serial recall test
demonstrate that it is pronunciation
time that determines capacity rather
than number of items
procedure
the reading speed was measured
Ps. were presented with sets of 5 words on a screen
the words were taken from either
one-syllable or poly-syllable sets
Ps. were asked to write down the 5 words in order immediately
after presentaion. they recalled several lists of both sets.
findings
recalled more short
than long words
recall as many words
as could say in 2 secs
strong positive correlation between
reading speed and memory span
conclusion
immediate memory span represents the
number of items of whatever length that
can be articulated in approximately 2
seconds
evaluation
might be that short words are
easier to recall than long words
because they are more familar
used unconnected words so didn't
reflect everyday use of the STM
lab experiment --> high control
length of time each condition was
seen for was able to be kept the same
one-way (linear) flow of
information
unitary, separate stores
long term memory
elements
encoding
Baddeley (1966)
aim
explore the effects
of acoustic or
semantic encoding
procedure
divided into 4 groups each
group shown 10 words from
one of the following lists:
acoustically similiar
acoustically dissimiliar
semantically similiar
semantically dissimiliar
after 20 mins doing another
task Ps. asked to recall in order.
carried out 4 times
findings
recall for semantically
similar than sissimilar
acoustic same for both
conclusion
LTM uses semantic encoding generally
evaluation
duration
factors affecting duration of LTM
childhood amnesia
young children bad at organising
and intergrating memories
how duration is measured
recognition better than free recall
thorough learning
Bahrick et al. (1975)
aim
establish the existence of very long term
memory and see whether there was any
difference between recognition and recall
procedure
investigators tracked down graduates
of a high school over a 50 year period
392 graduates shown
pics from high school
recognition group:
match name with pic
recall group: name
people in pics
findings
recognition
90% -- 14 years
80% -- 25 years
75% -- 34 years
60% -- 47 years
recall
60% -- 7 years
>20% -- 47 years
conclusion
certain types of info
for almost a lifetime
VLTM better in
recognition than recall
evaluation
meaningful stimulus
--> memories of own life
drop at 47 due to general
decline or limit of duration??
strengths
matches with the processes
people experience in real life
explains memory stores in terms
of capacity, duration and encoding
MRI scans of different
tasks back up ideas
brain damage supports
separate memory stores
weaknesses
too simple
brain damage shows that STM can be bypassed
working
memory model
central executive
problem solving and decision making
controls attention
flexible
limited storage capacity
phonological loop
acoustically encoded items
visuo-spatial sketch pad
mental images
episodic buffer
temporary storage system that
allows information from the
slave systems to be combined
with information from the LTM
strengths
explains how we store and
process information unlike
the multi store model
Baddeley has evidence for
the phonological loop (1975)
Baddeley has evidence
for sketch pad (1973)
weaknesses
know very little about central
executive ( most important part)
richardson (1984) argues that
it is difficult to identify the
function f the central executive
EWT
factors affecting EWT
anxiety
Loftus (1979)
aim
to find out if anxiety during a
witnessed incident affects the
accuracy of later identification
procedure
2 situations
1)) low key discussion. person comes
out with a pen and grease on him
2)) heated discussion, breaking glass,
chairs, paper knife covered in blood
Ps. had to identify
the man from photos
findings
1)) 49% accuracy
2)) 33% accuracy
evaluation
lab study
may lack ecological validity
later research supports finding
ethics
deception
upset by seeing bloodstained paperknife
conclusion
concentrates on weapon which distracts from appearance of man.
the anxiety of the weapon narrows attention and gives rise to very
accurate recall of the central details, but less about other things
yerkes - dodson
low anxiety --> low accuracy
middle anx --> high accuracy
high anxiety --> low accuracy
age
koriat (2001)
examined the amount of information
as well as the accuracy given by children
most researchers agree that children are worse than
adults at providing an accurate account of past events
and that the amount of information a child can recall
develops with age. This is due to lack of retrieval
capabilities as well as inferior capacity and duration.
researchers disagree on the accuracy of a child's memory. Studies such as
Geisselman and Padilla found that after being shown a film of a bank robbery,
children aged 7-12 were less accurate at reporting details of the incident.
However, Cassa et al and other studies have failed to find such differences.
misleading questions
Loftus and Pickerell (1995)
aim
to demonstratehow false
memories can be created through
suggestions made to the Ps.
Procedure
4 short narratives of their
childhood, allegedly
provided by family members
one of the Ps. was given false narrative which
was about when they got lost at a supermarket.
The details were from actual family shopping trips
findings
25% able to recall event even
though it never happened
repeated on people of all ages
conclusion
imaging events can
lead to false memories
cognitive interview
recreate context
recall everything
change perspective
change order
Fisher et al. (1989)
detectives in Florida were trained
to use the CI and were asked to use
it in real life interviews. compared
to the standard interview, there
was an information gain of 47%
Geisselman and colleagues (1988)
89 students were shown police training videos
of crime. Later they were interviewed by
American police, some of whom used the CI.
level of information
gained was measured by:
the number of correctly
recalled details
number of incorect
details or errors of things
that weren't in the video
the students interviewed
using CI recalled 41.5% of the
details compared to 29.4%
strategies for
improving memory
loci
involves identifying a set of familiar places and matching each
location to the item you want tot remember. Once you have
done this, you imagine walking through each loaction. The
locations act as retrieval cues because you know them all well.
mnemonics
peg word method
based on same principle as loci except that
the retrieval cues are a set of learned 'pegs'.
after you have learned these, you convert each
item you wish to remember into an image.
example: learning a set of objects that
rhyme with numbers 1-20: 1 - gun, 2 - shoe...
example:shopping list: shooting a loaf of bread, walking on eggs...
organisational charts
create hierarchies to organise
material into meaningful patterns
Bower et al. (1969)
Ps. had to learn a list of words. The experimental
group saw words organised into a hierarchies and
control group saw random words. In total Ps. saw
112 words and the experimental group could
recall 65% on average compared to 19%.
rehearsal
Craik and Watkins (1973) identified
2 different forms of rehearsal
maintenance rehearsal
this is a technique mainly used by children,
which involves repeating things over and over.
elaborative rehearsal
form of rehearsal requires you to make the information you
repeat meaningful in some way. Elaborated memories are easier
to recall, because their meanings will help you to recall them.
spacing
in a review of 63 studies, Donovan and Radosevich
found that people who distributed their studies had
a better learning and recall rate than those who
crammed their studies into a short period of time.