Memory Flashcards
Capacity
= the no. items a memory store can hold at any one time.
STM Study: Jacobs (1887) & Miller (1956) - study of immediate digit span.
-Participants recall random lists of digits/no. in correct order.
-List increases by one digit/no. each time.
-Digit span measured at the point where participants can no longer recall the digits in the correct sequence.
STM Findings: STM capacity limited to 5-9 items (7 items of info +/- 2)
LTM Study: N/A
LTM Findings: unlimited.
Duration
= the length of time a memory store can store/remember an item for.
STM Study: Peterson & Peterson (1959) trigram retention study.
-Participants briefly presented with a consonant trigram (e.g. WGP)
-They were asked to count backwards in 3s from a random no. (to prevent rehearsal).
-Participants were asked to recall trigrams at different time intervals ranging from 3-18 seconds.
STM Findings: STM duration is brief wen rehearsal is prevented - up to 30 seconds.
Participants could recall 80% trigrams correctly after 3 seconds but fewer than 10% after 18 seconds.
LTM study: Bahrick et al (1975) - high school yearbook study.
-Tested nearly 400 American high-school graduates on their memory of former school mates.
-Used a variety of recognition and name-matching tasks.
LTM Findings: 30 seconds-lifetime.
-Memory better on recognition than recall.
-Memory began to decline after 47 years.
Coding
= the form in which the store remembers the item e.g. visually, acoustically or semantically.
STM Study: Conrad (1964) study of acoustic confusion.
-Participants were shown a random sequence of 6 consonants briefly on a screen.
-Some sounded similar.
-Some sounded different.
-Participants were then asked to write down the consonants in the correct order.
STM Findings: Mainly acoustic.
Participants found it more difficult to recall & made more errors on the lists of similar sounding consonants.
LTM Study: Baddeley (1966) Acoustic/Semantic encoding.
-Participants presented with 10 words from each of 4 categories:
1.Words that sound similar
2.Do not sound similar
3.Mean the same
4.Do not mean the same
-Rehearsal was prevented (counting) & recall tested after 20 mins.
LTM Findings: Mainly semantic
-Participants performed well on words with similar meaning.
-Baddeley concluded that this was because LTM codes for meaning.
Multi-store model
Proposed by Atkinson & Schiffrin (1968) consisting of 3 main stores: Sensory, STM & LTM.
Explains how info flows from one storage system to another:
-Info received through senses enters sensory store, constantly receive info, most receives no attention.
-If attention is paid to it it is transferred & processed by STM, if not attended to it is forgotten.
-If rehearsed efficiently it is transferred to LTM.
Sensory register
Particular registers for different senses:
-Iconic (vision)
-Echoic (sound)
-Haptic (touch)
= passive stores -> cannot control what enters & its functioning.
Constantly bombarded with info, so has mechanism for selecting relevant & discarding rest.
Capacity: Very large
Duration: Limited
-iconic = 500 milliseconds
-echoic = 2 seconds
Coding:
-iconic = visually
-echoic = acoustically
Evaluation points for multi-store model
+ Supporting case studies:
-Clive Wearing contracted viral infection & left with brain damage & major memory disruption.
-Episodic severely impaired, had difficulty recalling events from past e.g. wedding day.
-Basic semantic memory = relatively unaffected e.g. meanings of words.
-Displayed procedural memories e.g. tie shoelaces, walking, talking, complex piano pieces
->Points to clear distinction between LTM & STM, supporting proposal they are separate stores. Clear that virus just attacked STM.
+ Support from Serial Position Effect:
-Murdock (1962) presented participants with list of words to recall any order.
-Found that words at beginning & end of list recalled better than middle = serial position effect.
-Words at beginning = primary effect - rehearsed - LTM.
-Words at end = recency effect - STM (can stay up to 30 seconds without rehearsal).
->Provides existence for separate stores.
x Mere rehearsal doesn’t ensure transfer from STM to LTM:
-Bekerian & Baddeley (1980) found people didn’t know of changes to BBC radio wavelengths despite hearing info on average over 1000 times.
->Questions role of transferring info from STM to LTM - according to MSM info should have been rehearsed sufficiently.
x Info which isn’t rehearsed can be stored in LTM:
-Jenkins (1974) demonstrated some info can be retained in LTM even when participants not warned about recalling = incidental learning.
-Occurs due to interest, funniness, or personal relevance.
-> MSM cannot account for recall of this info, proposes that STM must rehearse in order for transfer, may not always be true.
Types of LTM
Endel Tulving (1985) one of first cognitive psychologists to realise MSM view of LTM = too simplistic & inflexible & thus proposed 3 LTM stores.
Can be divided into 2 main types:
-Declarative = ‘knowing that’ e.g. facts, details, events.
-Procedural = ‘knowing how’ e.g. how to do things.
Episodic memory
= refers to our ability to recall events from our lives.
WWW criteria:
-What happened
-Where it happened
-When it happened
Likened to a diary - memories of a single episode will include several elements e.g. people, places, objects, behaviours - all interwoven to produce a single memory.
Time-stamped: Yes (can remember when happened)
Awareness: Conscious effort to recall memories.
Brain localisation:
Initial coding - prefrontal cortex
Consolidation & storage - neocortex.
Memories of different parts of events - different visual, auditory & olfactory areas but connected in hippocampus to create memory of event rather than collection of separate memories.
Semantic memory
= contains general knowledge - our knowledge of the world.
Includes facts but in broadest possible sense.
Likened to an encyclopaedia & dictionary.
Time-stamped: No - less personal knowledge & more facts we all share.
Awareness: Conscious effort to access.
Brain localisation: some disagreement:
-some evidence of involvement of hippocampus & related areas.
-usage of several areas.
-coding mainly associated with frontal & temporal lobes.
Procedural memory
= memory for actions, skills or how we do things.
e.g. driving a car - (eventually) change gear without realising.
Time-stamped: No - we don’t often recall when we learnt.
Awareness: Without conscious awareness or great deal of effort.
Brain localisation:
Motor skills - prefrontal cortex, parietal cortex & cerebellum all engaged.
-Cerebellum = coordinate flow & timing of movements.
-Damage to cerebellum & basal ganglia = affect on procedural.
-> 1977 study of Alzheimer patients - discovered procedural memory functions better than declarative as it is less dependent on affected regions of brain (cerebellum & basal ganglia).
Evaluation of types of LTM
+ Research from Clinical Case Studies:
-Patient HM & Clive Wearing - both episodic severely impaired from amnesia - difficulty recalling events from past.
-Semantic relatively unaffected e.g. meaning of words.
-Procedural intact - how to tie shoelaces, Clive could still read music and play piano (professional musician).
-> Supports Tulving’s view that there are many different stores in LTM - one store can be damaged but others remain unaffected - clear evidence of different types of memory & stored in different parts in brain.
+ Support from neuroimaging evidence:
-Brain scan studies for different stores in brain e.g. Tulving et al (1994) got participants to perform various memory tasks while scanned (PET).
-Found episodic & semantic both recalled from prefrontal cortex - area is divided one on each hemisphere of brain. (Left for semantic, right for episodic).
-> Supports view that there is physical reality to different types of LTM within brain.
+ Real-life applications:
-Being able to identify different aspects of LTM allows psychologists to target certain types of memory in order to better people’s lives.
-Belleville (2006) demonstrated episodic memories could be improved in older people who had a mild cognitive impairment.
-Trained participants performed better on test of episodic after training control group.
-> Episodic most affected by mild cognitive impairment highlighting benefit of being able to distinguish between types of LTM - enables specific treatments to be developed.
Explanations for forgetting:
Interference
= occurs when 2 pieces of info conflict with each other - results in forgetting of one or both items, or some distortion.
Proposed mainly as explanation in LTM - once memory reaches LTM its more or less permanent, therefore any forgetting is most likely because we can’t get access even though available.
-> Interference between memories makes it harder for us to locate them, and this is experienced as ‘forgetting’.
Types of interference:
Proactive = when older memory interferes with a newer one
e.g. teacher learned many names in past - difficulty remembering new ones.
Retroactive = when a newer memory interferes with a older one
e.g. teacher learned so many new names - cannot remember old names.
Evaluation for inference as an explanation for forgetting
+ Research Support:
-Interference is worse when the memories (or learning) are similar - McGeoch & McDonald (1931)
-Studied retroactive by changing amount of similarity between 2 sets of materials.
-Participants had to learn a new list of 10 words until they could remember with 100% accuracy. They then learnt a new list.
-6 groups of participants who had to learn different types of lists: synonyms, antonyms, unrelated words, nonsense syllables, 3-digit no. & no new list (rested).
-When recalling original list again, synonyms produced worst recall.
-> Shows interference is strongest wen materials are similar.
+ Evidence from lab studies:
-Most consistently demonstrated findings in psychology. 1000s lab experiments carried out e.g. McGeoch & McDonald.
-Most studies show both types are likely to be common ways of forgetting LTM.
-> Lab experiments control effects of irrelevant influences & thus give confidence that interference is a valid explanation for some forgetting.
x Problems using lab studies to test:
-Much greater chance interference demonstrated in lab than real-life situations for 1 good reason.
-Stimulus materials in most studies are list of words - completely different to learning things in everyday life e.g. faces, birthdays.
-> Use of artificial tasks makes interference much more likely in the lab. Interference may not be as likely as explanation for forgetting in everyday life as it is in lab.
Explanations for forgetting:
Retrieval failure
-Insufficient cues - when info is initially placed in memory, associated cues are stored at same time.
If cues are not available at time of recall, it may make it appear you have forgotten when really due to retrieval failure - not able to access memories there.
Two types:
Context-dependent forgetting:
-occurs with external retrieval cues - forgetting when external environment is different at recall from how it was at coding.
Research - Godden & Baddeley (1975):
-carried out study using deep-sea divers as participants.
-divers learnt list of words either underwater or on land then asked to recall in either environment - 4 conditions.
-when learning in different environment to recall = 40% lower recall than others.
-external cues at learning different from ones at recall - retrieval failure.
State-dependent forgetting:
-occurs when internal retrieval cues - forgetting occurs when internal environment is dissimilar to when coded i.e. mental state (e.g. recall drunk, learned sober).
Research - Goodwin et al (1969)
-asked male volunteers to remember list of words when either sober or drunk (those in drunk condition 3x over UK drink driving limit).
-participants asked to recall lists after 24hrs.
Evaluation for Retrieval Failure as an explanation for forgetting
+ Applications in real-life:
-Cognitive Interview uses research findings from retrieval failure to improve recall from witnesses.
-Aims to recreate conditions in which individual first seen event e.g. weather, time, mood = context reinstatement.
-thought that this increases number of cues available & helps to access info from variety of different sources.
-Found to have improved recall by 34% over standard interview technique.
-> Supports as when we increase number of cues then our memory will improve as a result.
x Questioning context effects:
-Baddeley (1977) argues context effects are not actually very strong, esp in real-life
e.g. hard to find an environment as different from land as underwater.
-in contrast learning something in one room & recalling in another is unlikely to result in much forgetting as environments are generally not different enough.
-> Limitation as means real-life applications of retrieval failure due to contextual cues don’t actually explain much forgetting.
Working model
Baddeley & Hitch questioned existence of single STM store - argued that STM was far more complex than a mere ‘stopping off’ point - saw more as an ‘active store’ holding several pieces of info consciously thought about.
Compared to a computer screen where several operations are performed on current data.
They thought this because:
-If you do 2 things at once & are both visual tasks, you perform less well than if you do them separately.
-If you do 2 things at once & 1 is visual & 1 involves sound, there is no interference.
Central executive
Most important component in model - responsible for range of imp control processes:
-setting goals
-attention
-correcting errors
-switching attention between tasks
-retrieving info from LTM
-coordinating activity needed to carry out more than one processing task at a time.
Most important role = monitoring and coordinating the operation of the slave systems.
It is flexible - can process info from any modality & has some storage capacity (limited).
Phonological loop
Limited capacity.
Deals with auditory info & preserves order of info.
Loop - based on sub-vocal repetition - info goes round in a loop (i.e. repeating info in head)
Baddeley (1986) further sub-divided loop:
-phonological store = holds words you hear - like an ‘inner ear’
-articulatory process = used for words that are seen or heard - silently repeated (looped) - like an ‘inner voice’
Appears that phonological loop used for learning new words.
Phonological store ‘simply’ holds auditory data.
Visuo-spatial sketchpad
Referred to as ‘inner eye’
Visual and/or spatial info is temporarily stored here.
Visual = what things look like.
Spatial = relationship between things.
Sketchpad used when you have to plan a spatial task.
Also used when engaged in visual task e.g. working out how many windows in your house - most people create a visual image of their house in working memory.
Logie (1995) suggested sub-dividing store into:
-visual cache = stores visual material about form & colour.
-inner scribe = handles spatial relationships & rehearses & transfers info in visual cache to Central Executive.
Episodic buffer
Baddeley (2000) added 3rd slave system - needed a general store.
Slave systems = deal with processing & temp storage of specific kinds of info.
Central executive has no storage capacity - nowhere to hold info relating to both visual & acoustic info.
Episodic buffer = extra storage system - limited capacity.
-Integrates info from central executive, phonological loop & visuo-spatial sketchpad.
-Maintains sense of time-sequencing - basically recording events happening.
-Sends info to LTM.
Evaluation for working model
+ Research support: Dual-task studies:
-Dual-task performance (i.e. doing 2 things at once) supports existence of visuo-spatial sketchpad.
-Baddeley et al (1975) showed participants had more difficulty doing 2 visual tasks than both visual & verbal task at same time.
-Increased difficulty is because both visual tasks compete for same slave system.
-> Means there must be a separate slave system (V.S.S) that processes visual input and has a limited capacity.
+ Research support: word length effect:
-Describes the fact that people cope better with short words in working memory (STM) than long words.
-Seems PL holds amount of info you can say in 2 seconds (Baddeley et al 1975).
-Makes it hard to remember a list of long words compared to short.
-Longer words can’t be rehearsed on phonological loop because they don’t fit in.
-> Supports idea that capacity of PL is set by length of time it takes to say words rather than actual no. of words said.
+ Support from brain damaged patients:
-Patient KF - poor STM ability for verbal info but could process visual info i.e. difficulty with sounds but could recall letters & digits.
-> Suggests that just PL was damaged leaving other areas of his memory intact. Supports existence of a separate visual & acoustic store.
x Function of CE = unknown:
-Cognitive psychologists suggests CE = unsatisfactory & doesn’t explain anything.
-Baddeley recognised and said: ‘most imp but least understood component’.
-CE needs to be more clearly specified than it just being simply ‘attention’ e.g. some psychologists believe it to be more than 1 system with separate stores.
-The way in which it functions such as allocating resources is not clearly understood.
-> WMM cannot fully explain memory until we know more about its most vital store.
EWT: Misleading Info & Post-event discussion
Loftus showed eyewitness memories can be affected by leading questions.
Leading Q = Q that, either by its form or content, suggests to the witness what answer is desired or leads them to desired answer.
->Serious implications for judicial system, since jurors seem to be particularly convinced by EWT.
Study: Loftus & Palmer (1974) ‘Smashed/contacted’ car speed
Aims: investigated accuracy of memory after witnessing car accident, in particular if leading questions distort accuracy of immediate recall - people notoriously poor at estimating speed of car - likely to look for hints.
Experiment 1: effect of leading Q:
-lab experiment involving 45 students.
-shown seven short films of different traffic accidents.
-after each film given questionnaire to describe accident.
-one group given ‘hit’ question, other 4 given ‘smashed’, ‘bumped, & ‘contacted’.
Findings = estimated speed determined by verb:
-smashed - 41mph
-contacted - only 32 mph
Experiment 2: effect of post-event info:
-150 participants split into 3 groups.
-one given ‘smashed’, another ‘hit’, 3rd given no indication.
-week later asked if they saw any broken glass (there was not any)
Findings:
-smashed - 32% claimed to see glass
-control group - only 12%
Conclusion = memory recall can be distorted by language used.
-Participants had different interpretations due to use of verb -unclear whether due to demand characteristics or genuine change in memory.
-Leading Q can be part of post-event discussion - when more than 1 witness to event, may discuss what they saw -> may influence accuracy of recall.
Evaluation of Loftus’ research (misleading Q & post-event discussion)
+ Experimental support for post-event discussion:
-Loftus study - 120 college students who’d visited disneyland in childhood asked to evaluate advertising material, fill out questionnaires & answer questions about trip.
-Group 1 read fake ad with no cartoon characters, group 2 read fake ad with no cartoon & exposed to cardboard cut-out of bugs bunny in room, group 3 read fake ad featuring bugs bunny, group 4 read fake ad featuring bugs bunny & saw cardboard cut-out.
-Group 1 = control, other groups contained some post-event info.
-30% group 3 & 40% group 4 claimed to have met bugs bunny at disneyland (not true).
->Shows how post-event info can create inaccurate memory, demonstrating memory is changeable & vulnerable to inaccuracy.
+ Applications of findings:
-Important contribution in understanding the unreliability of EWT.
-Seems clear from research that memory for events can be distorted in light of misleading-info.
-Important implications in way police question witnesses & questioning in court - urged to use as few leading Q as possible.
-Based on evidence, the Devlin Report (1976) recommended trial judge be required to instruct jury that it is not safe to convict on a single EWT alone except in exceptional circumstances or when substantial evidence.
-> Research into EWT is one area in which psychologists believe they can make an important positive difference to lives of real people.
x Lacks ecological validity:
-Lab experiment may not represent real life as people don’t take experiment seriously and/or they are not emotionally aroused as they would be in a real accident.
-Witnessing genuine accident = alarming, stressful & emotional experience - may alter memory in ways that don’t happen in safe lab experiment.
-e.g. Forster et al (1994) found if participants thought they were watching real-life robbery & responses would influence trial, identification of robber would be more accurate.
-> Studies using artificial tasks may tell us very little about how leading questions affect EWT in real-life accidents or crimes.
x Lacks population validity:
-Use of students as participants = not representative of general population in a no. of ways.
-Importantly they may be way less experienced drivers so less confident in ability to estimate speeds.
-> May have influenced them to be more swayed by the verb in the Q & in turn reduces validity of findings.
EWT: Anxiety
Jurors often place considerable importance on evidence provided by EW (i.e. eyewitness memory).
Baddeley (1997) has reported that 74% suspects were convicted in 300 cases where EW identification was only evidence against them.
Numerous research studies have identified several problems with EWT, including anxiety at time of incident, that is, during encoding stage of memory process.
When considering reliability of EWT it is important to bear in mind the type of crime being recalled - some involving violence are associated with high levels of anxiety in victims or bystanders.
Whether such anxiety leads to unreliable remembering depends on no. factors.
