memory Flashcards
what are the 3 processes that memory uses
- aquiring information
- storing information over time
- retrieving information
what does the term capacity refer to
the amount of information that can be stored in the memory at any one time
what does the term duration refer to
the length of time that information can be stored for
what does the term encoding mean
the way that information is stored (how it is represented)
eg. visual, acoustic, semantic
sensory memory:
1. capacity
2. duration
3. encoding
- very large
- milliseconds
- mainly visual, can be sound and touch
what is the sensory memory
a storage system that holds information in a relatively unprocessed form for fractions of a second after the physical stimulus is no longer available
it allows information from successive eye fixations to last for long enough to become integrated and make a continuous image of our environment
what did atkinson and shriffin propose about the sensory memory
they proposed that there are 3 separate sensory stores to accommodate different inputs
what are the 3 sensory stores
iconic, echoic and haptic
what is the iconic sensory store relating to the sensory memory
visual images kept for a short period of time, important as it helps integrate visual experience
what is the echoic sensory store relating to the sensory memory
auditory senses kept for a short period of time. duration = 250 milliseconds to a few seconds
what is the haptic sensory store relating to the sensory memory
sensory memory retains physical senses of touch and internal muscle tensions
who conducted research into the sensory memory
Sperling (1960)
what was sperlings research into the sensory memory
studied the sensory memory for vision (iconic store) by using a device that can flash pictoral stimuli onto a blank screen for very brief instances.
using this device, he was able to ask subjects to remember as many letters as they could from a grid of 12 symbols that was displayed for 50 milliseconds
he found that they could only recall around 4 of the symbols before the grid faded from sensory memory
how did sperling investigate the duration of the sensory memory
if there was a delay between presentation of grid and sounding of tone, more information was lost (0.3 second delay = 50% lost, 1 second delay = 66% lost)
how did sperling investigate the capacity of the sensory memory
‘partial report’ technique
Ps had to distinguish between 3 tones
grid displayed for 50 ms
each tone referred to a row of 4 letters in the grid
high tone = top row, mid tone = middle row, low tone = bottom row
on average, Ps could recall 3/4 symbols from any row
they were not aware of the tone before the grid was displayed
suggests iconic store can retain approx 76% of data received
what does miller say the capacity of the short term memory is
7 +/- 2
this became known as millers magic number 7
what method did miller use to research the capacity of the short term memory
he used digit span experiments
what is a digit span experiment in researching the capacity of the short term memory
reading out a list of random digits and requiring Ps to repeat them back in the correct order
begin at 3 digits and steadily increases
the sequence length as which the Ps are correct 50% of the time is their digit span
what are the strategies for increasing the capacity of the short term memory
chunking
rhythmic grouping
reheasal
what is chunking in increasing capacity of the STM
grouping the numbers so you can remember 7 +/- 2 chunks of numbers
typically used in remembering phone numbers/bank details
what is rhythmic grouping in increasing capacity/affecting capacity of the STM
remembering numbers with a certain rhythm
typically used in remembering phone numbers
what is rehearsal in increasing capacity of the STM
repeating the information over and over again
what factors affect the capacity of the STM
what is already in your long term memory
reading aloud
rhythmic grouping
pronunciation time
short term memory
1. capacity
2, duration
3. encoding
- 7+/- 2
- 15-30 seconds
- acoustically
Conrad - encoding in stm
- looked at if people use acoustic coding in stm even when information is presented visually
- Ps shown a random sequence of 6 consonants on a screen in rapid succession
- consonants were acoustically similar or dissimilar
- Ps had to write them down in order
- most errors occured with acoustically similar consonants
- concluded that info is stored acoustically in the stm
Brandimonte
- visual coding can be superior in stm
- Ps presented with 6 line drawings and asked to memories them
- then form mental image and subtract a specified part from each one
- asked the name the resulting image
- 2.7/6 items on average
- another group had the same task but couldn’t turn image into verbal code
- 3.8/6 on average
long term memory
1. capacity
2. duration
3. encoding
- huge capacity with no upper limit
- a lifetime
- semantically
evaluating the multi-store memory model - case study HM
- brain surgery removing hippocampus
- normal stm
- unable to transfer new info into his ltm
- proves there are different stores
evaluating the multi-store memory model - case study CW
- impaired stm - 7 sec duration
- unable to transfer new info into ltm + difficulty retrieving from ltm
- remember procedural memories - piano
- proves separate stores
evaluating the multi-store memory model - case study SB
- retrograde amnesia
- brain scan showed almost no blood flow in right temporal lobe
- can make new memories
- suggests ltm is in right temporal so multiple stores
AO3 for case studies evaluating the multi store model
- often only one type of memory is damaged which suggests multiple stores
- also suggests different types of ltm (CW - procedural)
- suggests memories are more complex than msm
- case studies have high validity but low reliability
general evaluation of the multi store model of memory
- too simplistic
- suggests rehearsal is the only way to transfer thoughts from stm to ltm
- only focuses on the process of remembering things not what is being remembered
who created the multi-store model of the memory
Atkinson and Shiffrin
who created the working memory model
Baddeley
what is the central executive
- supervisory system
- controls flow of information, problem solving, decision making and attention
- limited storage capacity
what is the phonological loop
- stores limited number of speech based sounds for brief periods
- made up of two parts:
phonological loop (inner ear) = allows acoustically coded items to be stored
articulatory control system (inner voice) = allows subvocal repetition of items to be stored
what is the visuo-spatial scratchpad
- stored visual and spatial information
- inner eye
- responsible for setting up and manipulating mental images
- limited capacity
what is the episodic buffer
- function is to retrieve material from the ltm to meet requirements of working memory
- combines material in ltm when the working memory needs it - integrates materials from different sources
- limited capacity
what are the strengths of the working memory model
- explains more than the msm
- applies to real life tasks (reading = phonological loop, problem solving = central executive, navigation = visuo-spatial scratchpad)
- supported by dual task studies (Baddeley and Hitch)
- does not overemphasise the important of rehearsal for stm retention
what are the limitation of the working memory model
- Leiberman
- little direct evidence for how the central executive works and what it does - capacity never been measured
- only involved stm so is not a comprehensive model of the memory
Leiberman
- criticises the wmm as the visuo-spatial scratchpad implies that all spatial information was first visual
- points out that blind people have excellent spatial awareness although never having any visual information
- argues the visuo-spatial scratchpad should have separate components for visual and spatial information
what are the different types of long term memory
procedural
episodic
semantic
types of long term memory:
1. procedural
2. episodic
3. semantic
- skills, not time stamped, unconscious
- events, time stamped, conscious
- facts/knowledge, not time stamped, conscious
how do the case studies HM + CW prove the existence of multiple types of long term memory
- episodic memory was severely impaired for both (difficulty recalling events)
- semantic memories relatively unaffected (knew meaning of words)
- procedural memories intact (could walk + talk, CW could play piano)
how do brain scans prove the existence of multiple types of long term memory
- evidence from brain scanning studies that different types of memories are stored in different parts of the brain
Tulving
- Ps performed various tasks whilst brains were scanned with PET scanner
- found that episodic + semantic both recalled from the pre-frontal cortex
from which parts of the brain are the different types of long term memory stored
semantic = left pre-frontal cortex
episodic = right pre-frontal cortex
procedural = cerebellum + basal ganglia
evaluation of the different types of long term memory (AO3)
- HM + CW - high validity but can’t control variables (unreliable), can’t generalise
- conflicting neuroimagery as some studies find episodic on right pfc and semantic on left whilst others that left pfc does encoding for episodic and right does retrieval of episodic
- real world application as it helps use to explain memory problems, can help develop treatments linked to different types of memory
what are the explanations for forgetting things
- interference
- retrieval failure
what is interference
- when two pieces of information disrupt each other causing forgetting or distortion in memory
- forgetting of ltm is more likely because we can’t access them even though they are available
- it makes memories harder to locate and we experience this as forgetting
name the different types of interference
- proactive interference
- retroactive interference
explain the different types of interference
1. proactive
2. retroactive
- when an older memory interferes with a new memory (P = past affects recent)
- when a newer memory interferes with an older memory (R = recent affects past)
research on interference - Chandler
- found that students who study similar subjects at the same time often experience interference
- if the languages are similar, interference is more likely
research on interference - Postman
- lab experiment
- Ps split into 2 groups
- both had to remember a list of paired words (eg. cat-glass)
- control group only had one list
- second group also had to learn a second list where the first word was the same but second paired word was different
- Ps asked to recall the words on list one
- control group was more accurate
- suggests retroactive interference
research on interference - Baddeley + Hitch
- asked rugby players to try and recall the names of the teams they played so far that season
- results showed that accurate recall did not depend on time since the match
- the number of games played in the mean time was more influential
- validity as it showed real life interference
what is meant by retrieval failure
this is where information is available in the ltm but cannot be recalled because of the absence of appropriate cues
what is the encoding specificity principle
Tulving
a cue has to be:
1. present at encoding
2. present at retrieval
in order for information to be recalled
retrieval failure
1. context dependent
2. state dependent
3. organisation dependent
- recall depends on external/environmental cues (time, weather)
- recall depends on an internal cue (mood, sobriety, caffeine)
- recall is improved if the organisation gives a structure that provides triggers (consistent routine)
research on retrieval failure - Baddeley
- asked deep sea divers to memorise a list of words
- one group on beach, other underwater
- when asked to recall, half of the beach learners went underwater + vise versa
- results showed those who learnt + recalled in the same environment recalled 40% more than those who switched
research on retrieval failure - Goodwin
- investigated the effect of alcohol on state dependent retrieval
- when people encoded info drunk, more likely to recall it in the same state
- hid objects when drunk, unlikely to find when sober, found when drunk again
research on retrieval failure - Carter + Cassidy
- gave antihistamines to Ps
- drugs made them drowsy and changed ‘internal state’
- Ps had to learn and recall a list of words either on or off drugs
- when mismatched, harder to recall
- supports state dependent forgetting
what is an eyewitness testimony
evidence given by a witness to a significant events such as a crime, usually a verbal account, based on memory and not always accurate
Yerkes-Dodson inverted U hypothesis
anxiety affecting EWT
- theorised an optimum level of anxiety to improve/increase accuracy of recall
- deffenbacher used this to explain how the presence of anxiety affects recall accuracy
Loftus and the WFE
anxiety affecting EWT: weapon focus effect
- Loftus found that is a person is carrying a weapon, witnesses tend to focus on that instead of the offender
- negatively affects the ability to recall identifying features of criminals
- shows anxiety can divert attention
Christiansen + Hubinette
anxiety affecting EWT
- studied recall of witnesses to a real bank robbery
- contradicts inverted U hypothesis as they found that heightened levels of anxiety improved recall
Yuille + Cutshall
anxiety affecting EWT
- studied a real life shooting in a gun shop
- 21 witnesses, 13 took part in the study
- witnesses interviewed 5 months after the event, compared results to the original police interviews
- accuracy of recall remained, witnesses that reported the highest stress levels were the most accurate
Clifford + Scott
anxiety affecting EWT
- found that Ps who saw a film including a violent attack remembers less than the control group who saw a less stressful one
- witnessing real life crime is stressful therefore memory accuracy is negatively affected
what is a schema
knowledge packets/templates which are built up through experiences, they enable us to make sense of a familiar situation and aid the interpretation of new information
Cohen
role of schemas in EWT
- 5 ways that schemas might lead to reconstructed/distorted memory
- ignore - people ignore aspects that do not fit into their schema of the event
- storage - we can store central features without storing the exact details
- fill in - people try and make sense of a situation by filling in missing information
- distortion - people distort memories to fit their expectations
- guessing - people use schemas to provide a basis for guessing
Brewer + Treyens
role of schemas in EWT
- investigated the effect of schemas on visual memory
- 30 Ps, wait in a room for 35 seconds (one at a time)
- room designed to look like an office with 61 items
- some objects compatible with office schema, some were not
- Ps more likely to recall compatible objects, 8 Ps recalled the really incompatible object
- most errors were substitutions of objects compatible with schema, some errors were placement
- study shows people remember what is consistent with schema and filter out other things
List
role of schemas in EWT
- asked people to rate events in terms of their probability in a shoplifting scenario
- compiled a video of 8 different shoplifting acts which were rated into high and low probability
- shows the video to new Ps, recall tested after 1 week
- more likely to recall high probability events
Bransford + Johnson
role of schemas in EWT
- studied how schemas affect our ability to store information
- constructed prose passages that would be difficult to understand without context
- compared recall between groups with and without context
- they were asked to rate understanding
without = 2.3/5 understanding, 3/18 points recalled
with = 4.5/5 understanding, 6/18 points recalled
evaluation on the role of schemas affecting EWT
- schema theories criticised on several accounts
- a schema is a rather vague concept and the schema theory offers no explanation as to how they are acquired in the first place
Ceci + Bruck - factors
age of witness in EWT
factors they believed affecting childrens EWT:
- interviewer bias
- repeated questions
- stereotype induction
- encouragement to imagine and visualise
- peer pressure
- authority figures
Thomson
age of witness in EWT
- as the time between encoding and retrieval increases, recall declines in adults + children
- thomson suggests childrens EWT is likely to suffer more than adults from this
Lietchman + Ceci
age of witness in EWT
- effect of misleading information when questioning children
- they found that if 3-6 year old children were given repeated misleading information in questions, they eventually incorporated it into their memory
Ceci + Bruck - encoding
age of witness affecting EWT
- children lack an appropriate schema for the event witnessed
- makes it difficult for them to encode the event properly
- however, it can make children more accurate as adults schemas (expectations) may cause distortion in memory
Kent + Yuille
age of witness in EWT
- younger children were more likely than older children to select someone in a photo display that they had seen earlier even if the person was not in the display
- young children are able to correctly identify someone but will often choose someone anyway if the person is not there
what is meant by post event discussion
- possible source of misinformation
- after discussion with co witness or other person who has a different account of the event, they may distort their own story
- leads to contamination of memory
impact of post event discussion
- can lead to false arrests
- inaccuracy of EWT
why does post event discussion affect EWT
- conformity - social pressure/ feeling that co witnesses know something you don’t
- being unable to differentiate from what you see and what others tell you
who developed the cognitive interview
Geiselman + Fisher
what are the techniques used in the cognitive interview
- context reinstatement - visualising yourself back in the environment
- report everything - recall all details, even if they seem irrelevant
- changing perspective - recall the incident from someone else viewpoint
- reverse order - report the event in different temporal orders
how does context reinstatement improve EWT (CI)
- memory heavily influenced by external environment
- provides retrieval cues
how does report everything improve EWT (CI)
- we often summarise events
- small details may trigger more information to be remembered
- retrieval cues
how does changing perspective improve EWT (CI)
- memories can be retrieved through different routes
- retrieval cues
how does changing narrative order improve EWT (CI)
- discourages confabulations
- retrieval cues
Geiselman et al
- compared CI to SPI
- showed police training videos of violent crime to 89 students
- 48 hours later, interviewed with either CI or SPI
- tested for number of correct items + errors recalled
- error rates similar, CI recalled more details
Geiselman + Fisher
- found that CI words best when conducted within a short time following the incident/crime
Milne + Bull
- found that ‘report everything’ and ‘context reinstatement’ components were the key techniques in accurate recall
features of the enhanced cognitive interview (ECI)
- open ended questions
- context reinstatement
- free recall of events
- witness concentration of mental images
Fisher
- assessed police officers gathering facts when using ECI compared to SPI
- found ECI to be superior
Coker
- found that an ECI that stressed use of focused mental imagery increased accuracy compared to CI
- greater effect if conduced 1 week after the event, not immediately
what is the modified cognitive interview (MCI)
- modified version of CI + ECI to suit different purposes
- many are shortened versions as CI + ECI can be time consuming
Holliday
- showed children aged 4-5 + 9-10 a 5 minute video of a child birthday party
- interviewed the next day using SPI or MCI for children
- MCI more accurate
Verkampt + Ginet
- interviewed 229 children with CI, SPI or MCI
- found CI + MCI superior in providing accurate detail, especially versions of MCI without ‘change narrative order’
Memon, Meissner + Fraser
- meta analysis of 57 studies comparing CI, ECI, MCI + SPI
- involved children, elderly, young adults + people with learning disabilities
- CI = more accurate than non-CI techniques
- effect less evident with children, more with elderly
- MCI = more confabulations + inaccurate detail than CI + ECI
weaknesses of the cognitive interview
- time consuming
- confabulations
- not effective with suspect recognition
strengths of the cognitive interview
- widely used by police + other organisations
- development of MCIs means groups of witnesses can be interviewed effectively (eg. 45% of MCIs designed for children)
