Psychology - Memory

short term memory

a temporary store where small amounts of information can be kept for brief periods

long term memory

a permanent store where limitless amounts of information can be stored for long periods of time

capacity

the amount of information that can be held in a memory store

duration

the length of time information can be held in memory

coding

the format in which information is stored in the various memory stores

Jacobs (research into capacity of STM)

digit span technique - presenting participants with sequences of letters or digits at half second intervals which then was recalled in right order

AVG SPAN FOR DIGITS = 9.3 and LETTERS = 7.3

Miller (evaluation for research into capacity of STM - STRENGTH)

replicated Jacob’s study - ‘7 plus or minus 2’ and found chunking helps e.g. 1 9 8 8 - 1988

LIMITATION of Jacob’s study

artificial task - lacks ecological validity

Peterson + Peterson (research into duration of the STM)

participants shown a trigram and then had an interference task of different lengths (count down from specific number in 3s) to prevent rehearsal - 80% after 3 seconds and decreased as time increased

trigram

three letter nonsense word

STRENGTH of Peterson + Peterson’s study (duration of STM)

high levels of control of extraneous variables

LIMITATION of Peterson + Peterson’s study (duration of STM)

artificial task - lacks ecological validity

Bahrick et al (research into duration of LTM)

400 participants aged 17 to 74 asked to remember names, faces + free recall of classmates from yearbook → after 15 years = 90% faces, 60% free recall → after 48 years = 70% faces, 38% free recall

STRENGTH of Bahrick et al (duration of LTM)

high ecological validity as real life task of remembering faces etc.

LIMITATION of Bahrick et al (duration of LTM)

lack of control over extraneous variables e.g. how often looked at yearbook

Baddeley (research into coding of STM and LTM)

participants asked to recall four sets of words (acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar) → straight away = more mistakes in A, later = more mistakes in C

STRENGTH of Baddeley’s research (coding of STM and LTM)

standardised procedure so can replicate the study

LIMITATION of Baddeley’s research (coding of STM and LTM)

artificial task - lack of ecological validity

Multi-store model of memory

linear/sequential as unitary stores that are not sub-divided

sensory register

incoming information from the senses is received in the sensory store

capacity = unlimited

duration = 0.5-3secs

coding = any modality

forgetting = decay

short-term memory info

capacity = 5-9 items

duration = 15-30secs

coding = acoustic (sound)

forgetting = displacement

long-term memory info

capacity = unlimited

duration = up to a lifetime

coding = semantic (meaning)

forgetting = interference and decay

Glanzer and Cunitz (STRENGTH of MSM)

free recall memory tests showed people more likely to remember words from beginning (primacy effect - rehearsed + enter LTM) and end (recency effect - remain in STM for recall) but not middle as displaced

HM (STRENGTH of MSM)

surgery to cure his epilepsy caused damage to his hippocampus and so couldn’t lay down new LTM but STM intact e.g. repeatedly read same articles and never recognised his psychologists

Peterson + Peterson (STRENGTH of MSM)

supports role of rehearsal as forgetting occurs when rehearsal is prevented from the interference task

LIMITATION of MSM

role of rehearsal not important as may remember details from an article despite no rehearsal

research - TULVING + BADDELEY AND HITCH (LIMITATION of MSM)

TULVING - different types of LTM

BADDELEY + HITCH - several different components that work independently in STM

episodic memory

personal experiences e.g. first day of school

• linked to time + place

• conscious recall needed

• declarative (can be put into words)

semantic memory

knowledge of the world e.g. remebering WW1 started in 1914 or rules of football

• begin as episodic but lose association

• conscious recall needed

• declarative (can be put into words)

procedural memory

motor or action based on muscle memory e.g. tying a shoelace

• repetition and practice

• unconscious recall

• non-declarative (cannot be put into words)

HM (STRENGTH of types of LTM)

could still form procedural memories but no episodic or semantic ones e.g. could draw figure in reflection of mirror but can’t remember learning it

Clive Wearing (STRENGTH of types of LTM)

musician suffered rare brain infection - had procedural memories like playing piano but if asked would say no as damaged episodic memories

Research support (STRENGTH of types of LTM)

brain scanning techniques - different areas of brain active when different kinds of LTM are active

• episodic = hippocampus + frontal lobe

• semantic = temporal lobe

• procedural = cerebellum + motor cortex

Cohen + Squire (LIMITATION of types of LTM)

accept procedural memories but argue semantic + episodic are the same store as they call them declarative memories

Working Memory Model

Baddeley + Hitch

central executive

pays attention to incoming information and directs it to the other ‘slave’ systems for further processing - involved in decision making and has a very limited capacity whilst being modality free

phonological loop

1) phonological store - acoustically coded information for a limited amount of time

2) articulatory process - deals with speech production as acts as a verbal rehearsal loop when preparing to speech - 2 secs worth of speech capacity

visual spatial sketchpad

processes visual and spatial information, dealing with movement and action as well as still images - limited capacity

• Logos proposed could be subdivided into visual cache and inner scribe

episodic buffer

a general storage facility, holding and combining information from the other systems but also the LTM - maintains sense of time and is limited to 4 chunks of info

Shallice + Warrington (STRENGTH of WMM)

studied KF who was in a motorcycle accident where by his long-term memories were intact but had partial difficulties with STM - process visual info like letters but no verbal material

Baddeley + Hitch (STRENGTH of WMM)

dual-task studies - participants asked to recite aloud a list of six digits while simultaneously checking sentences - could do both as different components (phonological + visuo-spatial)

BUT, when both visuo-spatial, they can’t do it e.g. couldn’t track a light whilst describing letter F

PET scans (STRENGTH of WMM)

different brain areas activated when doing verbal and visual tasks

LIMITATIONS of WMM (x2)

1. not comprehensive as focuses on STM and doesn’t explain how info passed on (MSM > WMM)

2. insufficient info about central executive despite most important as limits understanding

forgetting

the failure to retrieve memories

interference

when similar material is confused causing problems with recall from the LTM

proactive interference

forget new info e.g. the memory of an old phone number disrupts attempts of recall of a new one

Keppel and Underwood (research into proactive interference)

recall of consonant trigrams after interference tasks - found the trigrams at the start were almost always remembered which could suggest they had entered the LTM and interfering with memory of later trigrams

retroactive interference

forget old information e.g. the memory of a new car registration prevents recall of a previous one

Schmidt (research into retroactive interference)

participants who grew up in the same area completed questionnaire with map of the area and had to name street names + the number of times they’d moved - never moved = 23 streets, 8+ = 10 streets

Baddeley + Hitch (STRENGTH of proactive and retroactive interference)

rugby players asked to recall the names of the teams they had played that season, week by week, and showed accurate recall did not depend on how long ago the matches took place but number of games in the meantime

methodological criticisms (LIMITATION of research into proactive and retroactive interference)

• Keppel and Underwood - artificial task so may lack motivation and so hard to generalise

• Schmidt - lack control of extraneous variables e.g. practice of street names

individual differences (LIMITATION of research into proactive and retroactive interference)

some people less affected by proactive interference

• Kane and Eagle - greater working memory span were less susceptible to proactive interference

LIMITATION of research into proactive and retroactive interference (x2)

1. only explains some situations for forgetting

2. better explanation = absence of cues

Tulving + Pearlstone (no meaningful link)

participants given 48 words to learn belonging to 12 categories then asked to free recall without cues where 40% correct or with cues where 60% were correct

Godden + Baddeley (lack of environmental cues - context dependent forgetting)

researchers recruited scuba divers as participants and arranged for them to learn a set of words either on land or water in 4 categories

1. learn on land, recall on land

2. learn on land, recall underwater

3. learn underwater, recall on land

4. learn underwater, recall underwater

highest recall (40% more words) = initial context matched recall environment

Carter + Cassaday (lack of internal cues - context dependent forgetting)

gave anti-histamine drugs to participants which made slightly drowsy - internal physiological state different from normal state of being awake and alert

1. learn on drug, recall on drug

2. learn on drug, recall off drug

3. learn off drug, recall on drug

4. learn off drug, recall off drug

complete memory test - higher score when no mismatch between internal state

application (STRENGTH of research on retrieval failure)

applied to the cognitive interview technique as context reinstatement is used to improve memory of eyewitness (asked to recall environment)

LIMITATION of research on retrieval failure

lab based and not everyday memory tasks meaning they cannot explain all occurrences of forgetting e.g. ability to ride a bike

Godden + Baddeley (LIMITATION on research on retrieval failure)

replicated underwater experiment but used recognition not recall and made no effect

misleading information

incorrect info given to the eyewitness usually after the event e.g. leading questions and post event discussion

leading questions

one phrased in such a way that it suggests a particular answer to the witness

Loftus + Palmer (leading questions)

45 students shown 7 films of different traffic accidents then given a questionnaire asking them to describe the accident - estimate speed either when they ‘contacted’, ‘collided’, ‘smashed’ or ‘bumped’

1. highest estimate = 41mph = smashed

2. lowest estimate = 32mph = contacted

Loftus + Zanni (leading questions)

showed 100 participants a film of a car crash and then asked either ‘Did you see the broken headlight?’ or ‘Did you see a broken headlight?’ - 7% of the ‘a’ participants said yes vs 15% of ‘the’

positive application (STRENGTH of research on leading questions)

police officers now careful on how they phrase their questions when interviewing eyewitness in order to improve recall and reduce false convictions

low mundane realism (LIMITATION of research on leading questions)

uses artifical stimuli and so results may be differnt in real-life scenarios

Yuille + Catshall (LIMITATION of research on leading questions)

real life shooting in Canada where shop owner shot dead a thief and of 21 witnesses, 13 were studied - interviewed 4-5 months after shooting including two leading questions BUT maintained accuracy

post event discussion

when co-witnesses to a crime discuss it with each other their eye witness testimonies may become contaminated as they combine mis-infprmation from other witnesses with their own memories

Gabbert et al (research on post-event discussion)

eyewitnesses watched a short film of a girl stealing money from a wallet either in pairs or individually - those in pairs watched different videos but didn’t know and then discussed

• 0% error in control group

• 71% error in pairs when recalling stuff they didn’t see

Goodwin et al (research on post-event discussion)

shown slideshow of a crime committed in a college bookshop with a co-witness who was a confederate and deliberately provided misleading info

• public report =recalled incorrect info

• private report = no incorrect info

social pressures play a factor

LIMITATION of research on post event discussion

lacks ecological validity so may not take it seriously

Gabbert’s study (LIMITATION of research on post event discussion)

not entirely clear whether distortions obtained reflect problems with memory or reflect social pressures

real life support (STRENGTH of research on post event discussion)

Oklahoma bombing - one witness claimed to have seen the murderer with an accomplice but initially no one agreed - then others began to recall the same but eventually the first witness remembered there was no accomplice

Deffenbaucher (anxiety affecting accuracy of EWT)

meta-analysis of 21 studies on anxiety and accuracy of recall and found that stress performance relationship followed an inverted ‘U’ shape

Loftus et al (anxiety affecting accuracy of EWT)

showed participants a series of slides of a customer in a restaurant and in one version the customer pulled out a cheque and in the other they pulled out a gun - participants then given a line-up - technology measured eye fixation

• 39% of people correctly identified the suspect in the cheque condition

• 11% for the gun condition (significantly longer eye fixation time on gun)

Loftus + Burns (STRENGTH of research on anxiety)

supports Deffenbacher’s research as showed participants a violent version of a crime in which a boy was shot in the face and had significantly impaired recall

methodological criticisms (LIMITATION of research on anxiety)

1. Loftus - artificial so may lack motivation

2. Yuille + Cutshall - lack control of extraneous variables e.g. how often talk about crime

3. Deffenbaucher - too simplistic and subjective

Yuille + Cutshall (LIMITATION of research on anxiety)

rated how anxious participants felt after incident and those most stressed were most accurate (88% vs 75%) as may be more serious or could be closer etc.

Geiselman et al (Cognitive interview)

created the technique which is considered more effective than standard police interview

Cognitive interview order

1. context reinstatement - recall both environmental and emotional context of event e.g. weather and what you were thinking/feeling as act as cues

2. report everything - every detail as may not realise importance and may help recall significant info

3. recall from a changed perspective - encourages many retrieval paths meaning brain more active

4. recall in reverse order - prevent schema filling in gaps/reconstructing memories

Fisher (STRENGTH of research on CI)

used real police officers who were either trained on CI techniques or standard technique - interviews conducted using CI technique obtained 47% more info

Kohnken et al (LIMITATION of research on CI)

81% increase of correct info but also 61% increase in incorrect info compared to standard police interview

Milne + Bull (LIMITATION of research on CI)

combination of report everything and context reinstatement produced better recall so some more effective

LIMITATION of research on CI (x2)

1. takes more time and so not practical

2. generally less effective at enhancing recall when using at longer intervals of time after crime