Memory

what are the two types of memory?

short term memory (STM)

long term memory (LTM)

what is STM?

memory of things that have just happened

what is LTM?

memory of things that happened a while ago

what is capacity?

how much information can be held in memory at any one time

what are the research studies on capacity?

jacobs (1887)

what did jacobs (1887) find?

tested digit span - the number of items an individual can recall correctly

found the average span was 9.3 for digits and 7.3 for numbers

what did miller (1956) find?

suggested STM capacity is 7 items (+/- 2) - known as miller’s magic number

said that 5 words can be recalled as easily as 5 letters due to chunking - grouping sets of digits or letters into units or chunks to aid recall

what is the evaluation of capacity?

capacity of STM - alternative research says capacity is 4 items and the lower end of miller’s range is more appropriate, e.g. cowan (2001) and voget et al (2001)

size of the chunk - simon (1974) said there may be a shorter memory span for larger chunks, e.g. phrases

individual differences - jacobs (1887) said digit span increases with age, could be due to an increase in brain capacity or development of strategies such as chunking

what is coding?

how information is changed and stored in memory - done in different formats

coding for STM is acoustic

coding for LTM is semantic

what are the research studies on coding?

baddeley (1966a, 1966b)

what did baddeley (1966a, 1966b) find?

had four groups of participants with different sets of words:

1) acoustically similar words

2) acoustically dissimilar words

3) semantically similar words

4) semantically dissimilar words

participants were shown the original words and asked to recall them in the same order

when asked to recall immediately, they did worse with acoustically similar words

when asked to recall 20 minutes later, they did worse with semantically similar words

what is the evaluation of coding?

baddeley - may not be testing LTM, as it was performed in a laboratory setting with artificial stimuli

STM may not be exclusively acoustic - brandimok et al (1992) showed that visual coding is used for visual tasks when there was not verbal rehearsal in the retention period

LTM may not be exclusively semantic - frost (1972) showed long-term recall is related to visual categories as well as semantic, nelson and rothbart (1972) found evidence of acoustic coding in LTM

what is duration?

how long information can be stored in memory

duration for STM is around 18-30 seconds

duration for LTM is unlimited

what are the research studies on the duration of LTM?

bahrick (1975)

what did bahrick (1975) find about LTM duration?

tested the duration of LTM

used graduates of a high school aged 17-74 - tested recall using a yearbook

tested 2 types of recall

1. free recall - participants recalled names of individuals in their class, if they had left 15 years ago this had 60% accuracy, if they had left 48 years ago this had 30% accuracy

2. photo recognition - participants recalled the names of individuals whilst looking in their pictures, if they had left 15 years ago this had 90% accuracy, if they had left 48 years ago this had 70% accuracy

showed the length of time since attendance impacted the success of recall

what is the evaluation of the duration of LTM?

external validity - bahrick et al (1975) had high external validity

low levels of control - many variables that could have affected recall, e.g. rehearsal (looking at yearbook) and popularity

what are the research studies on the duration of STM?

peterson and peterson (1959)

what did peterson and peterson (1959) find?

tested duration of STM

participants were given a trigram (3 letters) and then told to count back from a 3 digit number until told to stop - could be for 3, 6, 9, 12, 15 or 18 seconds (retention interval)

they were then told to recall the trigram - recall was best after a retention interval of 3 seconds and worst for 18 seconds

what is the evaluation of the duration of STM?

external validity - low external validity

displacement - may be that the letters are displaced by the counting, rather than forgetting the information

what is the multi store model of memory (MSM)?

made by atkinson and shiffrin (1968, 1971)

describes how information moves through the memory stores

suggests memory is made up of three stores linked by processing

what are the three stores in the MSM?

sensory memory

STM

LTM

what is the sensory memory store?

where information from the environment enters the model from the five senses

has 2 main sensory stores:

1) ionic (visual)

2) echoic (auditory)

what is the coding, capacity and duration of the sensory memory store?

coding depends on the sense it is coming from - e.g. sound is coded acoustically

capacity is very large - the sensory register receives lots of different information, but not all of it receives attention so it doesn’t move to STM

duration is very short (milliseconds)

what does the STM store do in the MSM?

if information receives attention in one of the sensory stores it moves to STM

maintenance is performed to maintain information in STM - information is repeated over and over to remember it

what is the coding, capacity and duration of the STM store?

coding is mostly acoustic

capacity is 7 +/- 2 - miller’s magic number

duration is 18-30 seconds

what does the LTM store do in the MSM?

if information is rehearsed enough it transfers to LTM - prolonged rehearsal

in order to recall something from LTM, information is transferred back to STM - retrieval

what is the coding, capacity and duration of the LTM store?

coding is mainly semantic

capacity is unlimited

duration is unlimited

what is the HM case study?

HM received an operation to cure his severe epilepsy - his hippocampus was removed

following the surgery he lost the last 10 years of his memories, and could no longer make long-term memories - his memory only lasted for the duration of STM

what is the serial position effect?

murdock (1962)

participants were given a list of 20 words and asked to recall them from memory

they remembered the words at the beginning of the list - due to primacy effect (they are able to rehearse these words and transfer them to LTM)

they remembered the words at the end of the list - due to recency effect (words had not yet been lost from STM)

what is the evaluation of the MSM?

HM case study - showed STM and LTM are separate stores, however case studies are idiographic (can’t be generalised), and it is impossible to know if the same would happen to others as it would be unethical to repeat, lack of reliability

serial position effect - primacy and recency effect supports how information moves from sensory register to STM and LTM

model is too simple - defines STM and LTM as single stores, alternative models suggest STM and LTM are divided, model has a limited explanation

maintenance vs elaborative rehearsal - may be more than one type of rehearsal, maintenance keeps information in STM and elaborative is needed to transfer information to LTM (adds information/links it to other information in LTM)

what are the three types of LTM?

episodic

semantic

procedural

what is episodic memory?

ability to recall events from our lives - e.g. last visit to the dentist

memories are ‘time-stamped’ - remember when they happened

memories have multiple elements - e.g. surroundings, objects, people present

context may also be remembered as well as emotions felt

what is semantic memory?

knowledge about the world

memories are not ‘time-stamped’

less personal and easily shared with other people

may start as episodic memories as they are learnt based on personal experiences - as associations with events are lost, they become semantic

what is procedural memory?

memory for actions, skill and how to do things

can be recalled with little effort - many become automatic, e.g. tying a tie or shoelaces

might find these skills difficult to explain to others

what is the evaluation of the types of LTM?

case studies - HM and clive wearing support different LTM stores, but case studies are nomothetic and individual

neuroimaging evidence - different types of memories are stored in different areas of the brain, tulving (1994) PET scans

real life applications - can help people’s lives in a positive way and develop treatments, e.g. belleville (2006) showed episodic memories can be improved in older people with mild cognitive impairments

distinguishing between episodic and semantic - possibility of forming semantic memories without them being episodic first, e.g. hodges and patterson (2007), irish et al (2011)

declarative memory - cohen and squire said episodic and semantic memories are in one store called declarative memory, and procedural memories are non-declarative

what is the working memory model (WMM)?

suggested by baddeley and hitch (1975)

explanation of how STM is organised

concerned with the part of the mind that temporarily stores and manipulates information

what is the central executive (CE)?

attentional process

monitors incoming data, makes decisions, allocates slave systems (3 middle components) to tasks

coding is not limited - different information is coded in different ways

capacity is limited - CE can’t attend to too many things, no capacity for storing data

what is the phonological loop?

one of the three slave systems

deals with auditory information and preserves the order in which information arrives

divided into 2 parts:

1) phonological store - inner ear, stores words you hear

2) articulatory process - inner voice, words that are heard or seen, silently repeated as a form of maintenance rehearsal to keep them in working memory

capacity is 2 seconds

what is the visuo-spatial sketchpad?

second slave system

stores visual and/or spatial information

logie (1999) - can be split into 2 parts:

1) visual cache - stores visual data

2) inner scribe - records arrangement of data in the visual field

capacity is limited - around 3-4 objects

what is the episodic buffer?

third slave system - added later as a general store

temporary store for information - integrates visual, spatial and verbal information

maintains a sense of time sequencing - recording events that are happening

storage component of the CE and links working memory to LTM and wider cognitive processes

capacity is limited - around 4 chunks

what is the evaluation of the WMM?

baddeley and hitch (1976) - tasks requiring different components had better performance that ones requiring the same component, shows each component has limited capacity

brain scans - braver el al (1997), greater activity in the left prefrontal cortex when the CE was engaged

KF case study - poor STM for verbal information, but not for visual information, phonological loop was damaged

unclear about role of CE - may have separate components, EVR case study

unclear link between WMM and LTM - does not specify how information moves to LTM, LTM present but not explained

musical memory - can listen instrumental music and complete acoustic tasks, should not be possible

lab experiments and case studies - artificial stimuli, lack external validity, can’t generalise case studies

what is the comparison of STM in the MSM and WMM?

MSM - shows a unitary short term store that processes all information (sensory memory - pay attention - STM - rehearsal - LTM)

WMM - has many short term stores that process information differently as directed by the CE

what is the comparison of LTM in the MSM and WMM?

MSM - suggests a one way relationship between STM and LTM as information travels to LTM through rehearsal

WMM - suggests previous experiences stored in LTM have an influence on STM

what is the comparison of research support in the MSM and WMM?

MSM - murdock’s serial position effect (primary and recency effects), HM (could not transfer information from STM to LTM)

WMM - baddeley and hitch (1976) said that one store can’t do two tasks, KF had poor STM for verbal but good for visual (only phonological loop was damaged)

what are the two explanations for forgetting?

interference

retrieval failure

what are the two types of interference?

proactive interference - when an older memory interferes with a newer one

retroactive interference - when a newer memory interferes with an older one

what are the research studies on interference?

postman and underwood (1960)

mcgeoch and mcdonald (1931)

baddeley and hitch (1977)

what did postman and underwood (1960) find?

looked at how interference affects learning

participants had to remember a list of paired words from list A and list B

the experimental group were then another list of paired words from list A and list C

the control group were not given this second list

all participants had to recall the words on list A and list B - the recall of the control group was more accurate than the experimental group

showed the words from the second list interfered with the ability to recall the first list

what did mcgeoch and mcdonald (1931) find?

studied retroactive interference - investigated how similarity affected interference

participants learnt a list of 10 words until they were 100% accurate

they then learnt a new list of words - antonyms, synonyms, unrelated words, nonsense syllables, 3 digit numbers or no new list

recall of the first list depended on the second list - the more similar the list, the more interference occurred and worse performance was

what did baddeley and hitch (1977) find?

natural study of real life situation

rugby players were asked which teams they had played so far in the season - some players had missed games

accurate recall depended whether the players had played games since

showed retroactive recall

what is the evaluation of interference?

lab studies - show both types of interference can be replicated and increase validity

artificial materials - greater chance interference will be displayed in a lab, studies have low ecological validity, interference in everyday life may not be as strong as in a lab

interference only explains some situations of forgetting - the two memories need to be similar, anderson (2000) showed the extent of interference in forgetting is unclear

accessibility vs availability - interference could be temporary,

what is retrieval failure?

when information is forgotten due to insufficient cues

what is a cue?

a trigger of information that allows access to a memory

can be meaningful or indirectly linked by being encoded at the time of learning - stored in memory at the same time as information

there are two types of cues:

1) external cues - context dependent learning

2) internal cues - state dependent learning

what is the encoding specificity principle (ESP)?

if a cue is to aid recall, it must be present at encoding and retrieval - learning and recall

if the cues available at encoding and retrieval are different, there will be some forgetting

what are the research studies on retrieval failure?

abernathy (1940)

godden and baddeley (1975)

tulving and posta (1971)

what did abernathy (1940) find?

students were tested in four conditions:

1) in the same room they had learnt the information in with the same instructor

2) in the same room they had learnt the information in with a different instructor

3) in a different room with the same instructor

4) in a different room with a different instructor

found that those tested in the same room with the same instructor performed best

what did godden and baddeley (1975) find?

tested divers on lists of words in 4 conditions:

1) learn on land, recall on land

2) learn on land, recall underwater

3) learn underwater, recall on land

4) learn underwater, recall underwater

accurate recall was 40% lower in the non-matching conditions

what did tulving and posta (1971) find about cues?

participants were given 6 word lists of 24 words in 6 categories

after each list was presented, participants were asked to write down what they remembered, and after all of the lists were presented, there was a final recall of all of them - free recall

they were then given the categories of the lists and asked to recall what they could - cued recall

some participants had more lists than others, and those with more lists had worse performance - retroactive interference

when participants were given cues, effects of interference disappeared - remembered 70% of words regardless of the number of lists

suggested cues are more important than interference in explaining forgetting

what is state dependent forgetting?

forgetting due to a difference in states at the time of encoding and retrieval

research studies:

carter and cassaday (1998) - tested learning and recall using antihistamines, performance was worse when conditions didn’t match

goodwin (1969) - people who drank a lot they forgot where things were when they were sober, but when they drank again they could recall the locations

miles and hardman (1998) - people who learned words on an exercise bike recalled them better when exercising

what is the evaluation of retrieval failure?

tulving and posta (1971) - interference is not as important as retrieval failure, supports the importance of cues in recall

real life applications - smith (1979) said remembering the room the information was learnt in can assist recall

research support for importance of cues in recall - cues could be the biggest factor in forgetting from LTM

recall vs recognition - retrieval failure doesn’t apply to recognition, can’t explain why people forget this type of memory

cues don’t always work - effectiveness depends on the complexity of the memory

environments have to be very different for retrieval failure to have a significant effect

what are the factors affecting the accuracy of eyewitness testimony (EWT)?

misleading information - leading questions, post-event discussion

anxiety

what are leading questions?

questions often used by police after an incident

can affect the accuracy of EWT as information used after an event can have a retroactive interfering effect on recall

what did the first loftus and palmer (1974) experiment find?

looked at if speed estimates of a video of a car crash would be influenced by how the question was phrased

participants watched the video and then answered questions about the speed of the car, with different verbs describing the crash - 'how fast were the cars going when they hit/smashed/collided/bumped/contacted each other?'

estimates varied based on the verb used - estimates were highest for ‘smashed’ and lowest for ‘contacted’

what did the second loftus and palmer experiment (1974) find?

looked at if leading questions just changed responses of whether they actually altered memory

participants watched a video of a car crash and were placed in three groups:

1) were interviewed after and asked a question with the verb 'hit'

2) were interviewed after and asked a question with the verb 'smashed'

3) were not interviewed after

a week later they were asked a question about seeing any broken glass in the video when there had been none - positive answers for broken glass was highest for the 'hit' group and lowest for the control group

what is post-event discussion?

when co-witnesses to a crime discuss it with each other - this can contaminate their EWTs

this is because they combine information and misinformation from other witnesses with their own memories

what is source monitoring theory?

says memories of the event are genuinely distorted

eyewitness can recall information about the event (both accurate and inaccurate) but can’t recall where it came from - source confusion

what is conformity theory?

says eyewitness memories are not distorted by post-event discussion

eyewitness recall only appears to change because they go along with the accounts of co-witnesses - social desirability bias or because they genuinely believe that other witnesses are right and they are wrong

what did gabbert (2003) find about post event discussion?

looked at post event discussion

participants watched videos of the same crime from different points of view - each participant could see elements that others could not

the participants engaged in post-event discussion

found 71% of participants recalled aspects of the video that they didn't see but had picked up in the discussion - a control group with no discussion had 0% in comparison

what is the evaluation of misleading information?

real life applications to legal system - improving eye witness testimonies to crimes

artificial tasks - studies are in lab settings and they only watch a video, lacks ecological validity

response bias - individuals are biased to certain expectations, misleading information can impact bias and affect recall

individual differences - memory is biased towards certain information, misleading information can be quite powerful

what is anxiety?

state of physical and emotional arousal

there is research support for anxiety making eyewitness recall both better and worse

how can anxiety have a negative effect on memory?

causes psychological arousal in the body - prevents people from paying attention to important cues

what did johnson and scott find about weapon anxiety?

investigated the effect of weapon anxiety on recall

participants heard an argument in another room whilst in the waiting room in one of two conditions:

low anxiety condition - participants heard the argument then saw a man holding a pen with grease on his hands

high anxiety condition - participants heard the argument, then heard breaking glass and saw a man holding knife covered in blood

participants later picked the man out of a set of 50 photos - 49% of the low anxiety participants correctly identified him compared to 33% of the high anxiety participants

what is tunnel theory?

in stressful situations, attention narrows to focus on one aspect of the situation, and ignores everything else

how can anxiety have a positive impact on memory?

the stress of witnessing a crime or accident creates physical arousal

fight or flight is triggered - increases alertness and improves memory for the event, creating awareness of cues in the situation

what did yuille and cutshall (1986) find?

real life study of a shooting in a gun shop in vancouver - out of 21 witnesses, 13 agreed to take part

they were interviewed 4-5 months after the incident, and these interviews were compared with the original police interviews

witnesses also rated how stressed they had felt on a 7 point scale

there was little change in levels of accuracy - participants who reported higher stress levels were 88% accurate, compared to 75% for the less stressed group

what is the yerkes-dodson law?

yerkes and dodson (1908)

the relationship between emotional arousal and performance looks like an upside down U

deffenbacher (1983) - applied the yerkes-dodson law to EWT, found as anxiety increases memory becomes more accurate, but there is a point where the optimum level of anxiety is reached, and if an eyewitness experiences more stress than this, recall declines

what is the evaluation of anxiety?

ethical studies - lacks protection from psychological harm, participants may be traumatised, raises the question of whether the evidence gathered is worth it

weapons focus effect - not necessarily anxiety, could be surprise, pickel study, hair salon with raw chicken

alternative model - after the optimum level, anxiety doesn’t decline gradually, but rapidly due to mental effects (catastrophe theory)

lab studies - more vulnerable to demand characteristics, participant changes behaviour after figuring out experiment

neutral/field experiments lack control

what is the cognitive interview?

fisher and geiselman (1992)

said EWT could be improved by better interviewing techniques

based on psychological insights into memory

what are the four main techniques of the cognitive interview?

reinstate the context

order

perspective

everything

(ROPE acronym)

what is ‘reinstate the context’ in the cognitive interview?

the witness is asked to recall the original crime scene

they try to recall the environment and their mood

what is ‘order’ in the cognitive interview?

events are recalled in a different chronological order to the original experience

prevents people reporting expectations of how the events must have happened

what is ‘perspective’ in the cognitive interview?

witnesses recall the incident from other people’s perspective - e.g. other witnesses, the perpetrator

disrupts the effect of expectations and schema on recall

what is ‘everything’ in the cognitive interview?

witnesses are encouraged to report every single detail of the event, including ones that they aren’t sure about or think may be irrelevant

seemingly trivial details may be important or trigger other memories

what are the two reasons for the effectiveness of the cognitive interview?

retrieval - memory is more accurate when a person is in the same state at recall as at learning, asking the witness to recall their mood and the weather cues are provided to aid recall

leading questions - cognitive interview does not use leading questions so recall is improved

what is the enhanced cognitive interview?

fisher (1987) developed additional elements of the cognitive interview - these focus on social dynamics

includes reducing eye witness anxiety, minimising distractions, getting the witness to speak slowly, asking open-ended questions

what is the evaluation of the cognitive interview?

research support - kohnken et al (1999) did a meta analysis of 50 studies, showed cognitive interview is more effective than standard interviews

inaccurate information - increases the amount of inaccurate information (61%) as well as accurate information (81%)

some elements more valuable - reinstate context and report everything are the best combination of techniques

time consuming - requires training and longer interviews