Coding - the format of which inforrmation is stored in the various stores
Research on coding
Baddeley- different lists of words, some that were
acoustically similar , dissilmilar semantically similar
and dissimilar
The participants were asked to immediately repeat the list
of words. - they tend to do worse on acoustically similar
words.
If the participants were asked to recall the list after 20 mins did worse on
semantically similar words
Suggests that info is coded semantically in LTM
Evaluation on research into coding
ARTIFICIAL STIMULI
Baddeley used random used artificial words rather
than meaningful words
Cautious about generalising the
findings to different memory tasks
Capacity - How much
information the memory
stores can hold
Research on Capacity
Span of memory and chunking
Miller - 7+/-2
Capacity of STM
Evaluation of research into capacity
Not so many chunks
Cowan 2001 - concluded that STM was only four chunks
Duration - How long the information is stored for in the memory stores
Research on duration
Duration of STM
Peterson and Peterson - 24
students were given a trigram to
remember. they had to count
backwards from a 3 digit number.
they were stopped at 3,6,9,12,15
and 18 seconds
They found that as the time of the
retention interval increased the
amount of right answers decreased
Suggests that STM has a short Duration
18 - 30 seconds
Duration of LTM
Bahrick - High school yearbook test - photo recognition test and free recall
PPts who were tested within 15 years of
graduation were about 90% accurate in photo
recognition.
free recall - 60% accuracy
After 48 years recall declined to 70% recognition
Free recall - 30% accuracy
Suggests LTM Has a long duration
Evaluation into research for duration
Peterson and Peterson - meaningless stimuli
trying to memorise trigrams
does not reflect real life -
lacked external validity
Bahrick - confounding variables were not controlled
looked in yearbooks which means they could
have rehearsed them over the years
The multistore model
Sensory register
Stimulus from the environment
Two main stores - iconic memory - visual info -
coded visually
echoic memory - auditory info - coded acoustically
Short term memory
7+/-2
coded acoustically
18-30 seconds unless rehearsed
Maintenance rehearsal occurs when we repeat materials to ourselves over and over again it then passes onto the LTM
Long term memory
Unlimited capacity
Memories can last a lifetime
LTM is coded semantically - meaning
Memories are transfered to STM through a process called retrieval
Evaluation of the multistore model
Supporting research evidence -
strength - Baddeley we tend to mix
up words.
There is more than one type of STM -
shallice and warrington KF
There is more than one type of rehearsal -
Craik and Watkins - 2 types of rehearsal -
maintenance rehearsal and elaborative
rehearsal
Types of Long term memory
Episodic memory
Is the ability to recall events (episodes) from our lives
The memories are time stamped
Your memory of a single episode will include several elements such as people, places, objects, and behaviours all woven together to create one memory
You have to make a conscious
effort to recall episodes. you may
be able to do it quickly or it may
take a while but you are aware
you are looking for that memory
Semantic memory
This stores our knowledge of the world - This includes facts
This memory has often been linked
with a dictionary and encyclopedia
These memories are not time stamped
semantic memory is less personal and more about the facts
Procedural memory
This is our memory for actions and skills or
basically how we do things
We can recall these memories without
consciousness. such as driving a car or
riding a bike.
Our ability to do this depends on
the procedural memory
Evaluation of different types of LTM
Clinical evidence - HM and Clive
Wearing - episodic memory effected,
semantic memory unaffected. supports
Tulving's theory
neuroimaging evidence - brian scans
Real life application - allows psychologists
to target certain areas in peoples
memory to improve their lives
The Working Memory Model
The central executive
Co-ordinates the activities of the three slave stores
The central executive has a very limited processing capacity
Phonological loop
one of the slave stores it deals with the audirtory info
subdivided into
phonological store
Stores the words we hear
articulatory process
which allows maintenance rehearsal. the
capacity of the loop is believed to be two
seconds
Visuo-spatial sketchpad
Stores visual and/or spatial info when required
sub divided into
the visual cache - stores visual data
the inner scribe - records the arrangement of objects in the visual field
Episodic buffer
Added to the model by Baddeley in 2000
It is a temporary store for info intergrating
the visual, spatial, and verbal info processed
by other stores and maintaining a sense of
time sequencing
The episodic buffer links working memory to the
LTM and wide cognitive processes such as
perception
Evaluation of the working memory model
Clinical evidence - Shallice and Warrington - KF
Dual task performance - supports the
seperate existancee of the visuo-spatial
sketchpad. BAddeley showed that
people hadmore difficulty doing two
visual tasks at the same time. this is
because visual tasks compete. where as
if they are different tasks there is no
competition
Lack of clarity over the working memory
model - it doesnt really explain anything.
Explanations for forgetting.
Interference
Proactive
old memories get in the way of
recalling new memories
Retroactive
New memories get in the way of
recalling older memories
Study - McGeoch and McDonald -
Retroactive forgetting
PPTS had to learn a list of words. They were split
into six groups. 1. synonyms. 2. antonyms. 3. words
unrelated to the original list. 4. nonsense syllables.
5. three digit numbers. 6. no new list
the most similar material
(synonyms) produced the worst
recall.
This shows that interference
is strongest when the
memories are similar
Evaluation
Evidence form lab studies - This is a strength because lab
experiments control the effects of irrelevant influences and
thus gives us confidence that interference is a valid
explanation for forgetting.
Artificial materials- This is a limitation
because it makes interference much
more likely in a lab. Interference may
not be likely as an explanation for
forgetting in an everyday life as it is in
a lab
Real life studies - This study shows that
interference explanations can apply to at
least some everyday situations
Retreval failure
Encoding specificity principle
if a cue to help us it needs to be
present at encoding and at retreval
If there are no cues or if they are
different forgetting is likely to happen
Context-dependent forgetting
Badeley's divers - learn on land recall
on land or learn in water recall in water
got the best results
State dependent forgetting
Carter and Cassidy study - learn on drugs recall on drugs etc.
learning and recalling in the same state gave better
results that when learning and recalling in different
states
Evaluation
Supporting evidence - this is a strength
because it increases the validity of the
explanation of forgetting
Questioning context effects - this is a limitation because it
means that the real life applications of retreval failure due
to contextual cues don't actually explain much forgetting
Recall vs recognition - this is a limitation because it
means that the presence or absence of a cue only
affects memory when you test it in a certain way
Factors effecting eye witness testimonies
Misleading information
Leading questions
Loftus and Palmer - car accident video, questionnaire, changed
the verb different serverity e.g crash, smash, collided.
findings - the mean estimated of the speed of the car increased with
the serverity of the verb describing the incident
Response bias explanation - suggests that the wording
of the question has no effect on the ppts memory, but
it influences how they decide to answer.
substitution explanation - the wording of
the leading question actually changes the
ppts memory of the incident
post event discussion
Gabbert et al - showed each ppts different angles of the same
crime. Then the ppts discussed what they saw
findings were that 71% of the ppts mistakenly recalled
aspects of the crime that they did not see but had picked
up on in the group discussion.
Evaluation
Useful real life application - it makes a
huge positive impact on peoples lives
The tasks are artificial - it
tells us little about how
people would react if they
witnessed a real crime
individual differences -
younger people seem to give
more detailed accounts of the
crimes etc
The effects of Anxiety
Anxiety has a negative effect on recall
Johnson and Scott - knife with blood or pen with oil
They found that 49% with the pen picked
the man out of pictures
Only 33% with the knife could pick him out
the tunnel theory of memory argues that
witnesses attention narrows to focus on a
weapon because it is the source of the anxiety
Anxiety has a positive effect on recall
Yuille and Cutshall
shop owner shot someone interviewed the witnesses
The witnesses were detailed in their account. little change
after 5 months. the witnesses who claimed to suffer the most
stress were more accurate that the less stressed witnesses
contradictory findings
Yerkes Dodson law
Evaluation
Weapon Focus Effect may not be relevant
- it is due to unusualness rather than
anxiety and therefore tells us nothing
about the effect of anxiety on EWT
Field studies sometimes lack control - the
researchers have no control over what is said in
the post event discussion and it could be because
of extraneous variables that has effect on the
accuracy of EWT
Ethical issues - putting people at risk of
psychological harm
Improving the accuracy of EWT - cognitive interviews
Report everything - encouraged to say
every little detail about the event
Reinstate the context - return to the
original crime scene in their minds
Reverse the order events
should be recalled
chronologically in reverse
Change perspective - recall the
incident from someone else's view
point
Enhanced cognitive interview - focus on the social dynamics of
the interaction e.g eye contact and reducing anxiety
Evaluation
The CI are time consuming - spend more time on these than
standard police interviews
Some elements may be more valuable than
others - using combo of report everything and
context reinstatement they found they got more
information that was accurate from the witness
Supports for the effectiveness of the ECI- more
correct info than standard police interviews