Memory

Memory

1. STM/LTM

   • Capacity
     • LTM: Potentially infinite
     • STM: Can be assessed using digit span, Jacobs: average space for digits is 9.3 and for letters is 7.3, Millers magic number =7±2, chunking ↑ digit span
       • Miller's original findings haven't been replicated, Cowan discovered STM is limited to 4 chunks, Miller's range extensive
       • Size of chunks has an influence, shorter memory san for larger chunks, supports idea that STM has limited capacity
       • STM capacity isn't the same for everyone, Jacobs found recall increased with age, 8 yr old = 6.6 digits but 19 yr olds = 8.6 due to brain capacity or chunking, STM capacity not fixed and role of individual differences
   • Duration
     • LTM: Bahrick et al. tested 400 people on ability to remember classmates, photo recognition task, within 15yrs = 90% accurate, within 50yrs =70%
     • STM: Peterson & Peterson, Trigram and 3 digit number, retention interval, 90% correct over 3s RI, 20% over 9s, 2% over 18s, suggests STM duration is less than 18s as long as rehearsal prevented
       • Artificial because don't remember letter and symbols in everyday life, but do need to remember phone numbers or postcodes, some relevance
       • P&P didn't measure what it aimed to, asked participants to count numbers in STM which displaces syllables to be remembered, Reitman used auditory tones, shows forgetfulness in P&P due to displacement
   • Coding
     • Acoustic, visual or semantic
       • Visual codes used in STM, Brnadimonte found participants used visual in STM if visual task and prevented from rehearsal in retention interval, suggests STM is not exclusively acoustic
     • Baddeley used word lists to test acoustic and semantic in STM & LTM, struggled to remember acoustically similar words in STM, but semantically similar easier in STM, suggests STM coded acoustically and LT, coded semantically
       • LTM appears to be semantic but not always, Frost showed long-term recall not related to visual or sematic, Nelson and Rothbart found evidence of acoustic coding in LTM, shows coding in LTM varies
       • Baddeley's methodology criticised as STM tested by asking participants to recall word list immediately after compared to 20mins to test LTM, questioned if this is LTM, questions validity

2. The Multi-store Model of Memory

   • 1)Senses enter sensory input where it stays for >1s unless... 2)You pay attention, then transferred to STM and stored for >18s unless.. 3)It s rehearsed, then enters LTM where it stays for an unlimited amount of time unless.. 4)It is rehearsed, then sent back to STM
     • Psychologists proved that different areas of brain involved in STM/LTM, HM had hippocampus removed and could remember everything before but couldn't make new LTM, supports separate stores
     • MSM suggests LTM &STM unitary stores, research shows different stores in LTM e.g. maintenance rehearsal explains semantic LTM not episodic, MSM too simple
   • SUPPORTING EVIDENCE: Glanzer & Cunitz (list of words, immediate memory recall and delayed recall, recency and primacy effect) and Clive Wearing (could remember wife's name and how to play piano suggests stores are separate
     • Lab studies support LTM & STM being in separate stores, brain scans showed when LTM engaged hippocampus was active, supports MSM
     • Criticised for emphasis on maintenance rehearsal, suggested that enduring memories created by processing not maintenance rehearsal, remembered more words in task that involved deep processing rather than shallow, suggest rehearsal on its own not enough to explain creating LTM
     • MSM suggests STM before LTM, Logie suggests STM relies on LTM so can't come first e.g. chunking, suggests that STM part of LTM

3. The Working Memory Model

   • PHONOLOGICAL LOOP: Auditory info, phonological store - inner ear, articulatory processes - words seen or heard silently repeated
     • WMM accounts for dual-task performance, Baddeley and Hitch supported using T/F statements and articulatory loop and central executive, demonstrated dual-task performance and showed central executive a main component
     • Case studies support, KF short term forgetting greater than visual stimuli, shows brain damage restricted to articulatory loop, supports idea of separate visual and spatial system
     • Problem using case studies, process of getting brain injury traumatic and may change behaviour, perform worse on tasks and of unique individuals so can't be generalised, issue for WMM and supporting research
   • CENTRAL EXECUTIVE: Sends info to slave systems, limited capacity
   • VISUO-SPATIAL SKETCHPAD: Visual info, visual cache - stores info about visual items, inner store - stores arrangement of objects in visual cache
     • Strength of WMM is phonological loop and explanation of word length effect, explains people cope better with short words in LTM, phonological loop holds info for 2s, hard to rehearse words in this time, word length effect disappears when given a repetitive task, provides evidence for articulatory process
     • Central executive too vague, suggest only allocates resources and is essentially same as attention but others suggest more than one component, therefore WMM explanation not complex enough
   • EPISODIC BUFFER: Integrates info from 3 other stores and send it to LTM, limited capacity

4. Types of LTM

   • Episodic Memory: personal experiences e.g. memories
   • Semantic Memory: knowledge of the world shared by everyone e.g. pub quiz
     • Supported by brain scan research, episodic = hippocampus, semantic = temporal lobe procedural = cerebellum, supports separate stores
     • Support from case studies, HM couldn't form new LTM but retained old procedural ones, supports difference between types of LTM
     • Hard to reach conclusions studying brain damaged patients, process traumatic and can't generalise, hard to know what areas damaged until after death, can't establish a causal relationship between exact brain region and type of LTM
     • Support from Alzheimer's patients, found they retain ability to form new semantic memories but not episodic, another psychologist found the opposite, suggests episodic and sematic memories separate and that episodic memories may lead to semantic, but semantic may form on own
   • Procedural Memory: skils accquired through repetition and practise e.g. tying shoelace

5. Explanations for Forgetting: Interference

   • Retroactive Interference: NEW memory interferes with OLD, first discovered by Miller using nonsense syllables and a retention interval
     • Methodology a disadvantage, most used artificial word lists so irrelevant to everyday life, low in ecological validity even though interference supported by Baddeley & Hitch
     • Interference effects don't occur often in everyday life, two memories need to be similar so therefore interference irrelevant explanation for everyday forgetting, other theories needed for complete explanation
   • Proactive Interference: OLD memory interferes with NEW, Underwood 2 lists
   • Baddeley and Hitch, Rugby players: whole team asked to recall teams they played against, uninjured players had more games to interfere compared to uninjured
     • Question if interference effects are permanent or temp, discovered it occurs due to memories being temporarily inaccessible, supports view that interference effects availablity

6. Explanations for Forgetting: Retrieval Failure

   • Encoding Specificity Principle (ESP)
     • Tulving&Thomson: said memory more effective if info present at encoding is also present at retrieval, Tulving & Pearlstone: words grouped into catgories, free recall and cued recall of category name, free recall = 40% right, cued recall =60%
   • Context-Dependent Forgetting
     • Godden & Baddeley: Underwater vs on ground, found familiar things act as memory cues
       • Lots of research strengthens explanation, Tulving & Pearlstone and Baddeley, relevant to everyday life, high ecological validity
       • Can apply research to improve recall ie in exams, having exam in the same room in which you learnt info inproves recall, imagine being in classroom, research helps improve recall in rela life setiings
       • Retrieval cues don't always work, learnt info relates to more than just cues, e.g. learning word list involves simple associations which can be triggered by one cue, but when learning about Milgram there are complex associations that would need more complex cues
   • State-Dependent Frogetting
     • Goodwin: male students, tested recall when drunk vs sober, information easier to remember if in same mental state

7. Accuracy of EWT: Misleading Information

   • Leading Questions
     • A questions that suggests to the witness what answer is desired or leads them to the desired answer
     • Loftus & Palmer 1) 45 students shown films of RTA, given questionaire with one leading questions (speed) used different verbs FOUND: more impact suggested by verb higher the estimated speed
       • Lots of research into leading questions, Bugs Bunny, supported Loftus and Palmer study, shows effect misleading info has on creating inaccurate memories
     • Loftus & Palmer 2) participants in 3 groups shown film of RTA, returned week later and answered questionaire, critical question about broken glass FOUND: more people said broken glass, especially if violent verb used
       • Strength of EWT is application to criminal justice system, warned of problems, but DNA helped show weaknessed in testimonies, shows importance of EWT in making sure innocent are convicted
   • Post-Event Discussion
     • Conversation between interviewer and eyewitness after crime has taken place which may contaminate witness' memory of event
     • Conformity Effect: Co-witnesses reach consesnus view of what has happen, recall different or untrue things
     • Repeat Interviewing: Risk that comments from interviewer will become incorporated into recollection of events, leading questions may be used, serious when interviewing children
       • Criticism of EWT research is individual differences, elderly people find it hard to remember source of info so more prone to effect of misleading information, suggests individual diff should be considered when looking at reliability
   • Bugs Bunny: Loftus, tried to get them to remember meeting Bugs Bunny at Disneyland, they recalled touching tail and shaking hand, shows you can manufacture memory

8. Accuracy of EWT: Anxiety

   • Effects
     • Johnson & Scott: sat in waiting room 1) heard argument and man walking through with pen in grease (low anxiety) 2) heard argument, man walking through with paper knife covered in blood (high anxiety), asked to identify man. FOUND: 1)49% correct identification 2) 33% correct, anxiety focuses attention on central features of crime and away from physical features
       • Weapon focus effect criticised as reduced accuracy could be due to surprise, raw chicken study (scissors, gun, wallet and raw chicken), supports idea that WFE due to surprise not anxiety
     • Christianson & Hubinette: questioned witnesses to real bank robbery in Sweeden, witnesses were either high anxiety (close to action) or low anxiety (bystanders), interviews conducted 4-15mths later. FOUND: Better than 75% accuracy overall, high anxiety witnesses had best recall, showed anxiety doesn't reduce accuracy of recall
       • Strength was that it's a natural study, but contradicts J&S , could be because its a lab study or not enough anxiety created, Deffenbacher found in lab anxiety decreases accuracy, real-life show loss of accuracy, doesn't agree with C&H but suggests lab results still valid due to real-life support
       • Violence of crimes could affect recall, C&H involved real-life crime but, most others don't, Halford and Milne found victims of violent crimes more accurate than their recall of crime scene info, shows isn't simple rule of effect of anxiety on EWT
     • Deffenbacher reviewed 21 studies of anxiety on EWT, 10 showed high anxiety = high EWT accuracy, suggested Yerkes-Dodson effect (anxiety/arousal only moderate when EWT accuracy is enhanced, when anxiety extreme, accuracy reduced)
       • Individual differences, some more sensitive than others, tested and labelled participants as 'neurotic' or 'stable', found stable participants more accurate as stress increased, opposite for neurotic, individual differences should be considered for accuracy of EWT

9. The Cognitive Interview

   • Geiselman et al: 1) Mental reinstatement of context 2) Report everything 3) Change order 4) Change perspective
     • Weakness is amount of time and training needed, police officers suggest takes too much time and instead they use other strategies to get info, CI isn't used in police interviews
     • Problem evaluating CI as its used in collection of related techniques, Thames Valley Police use similar version but not changing perspectives, others have used just reinstate context and report everything, hard establish overall effectiveness of CI
     • Strength of CI is supporting evidence, meta-analysis found increase of 34% in amount of correct information gained from CI but done in lab, effectiveness could be due to individual elements rather than all elements combined, CI is effective technique for increasing accessibility of stored info
     • Criticism is that used for quantity of info over quality, designed to increase quantity without compromising quality, found increase of 8% in correct information but also 6% increase in incorrect info when CI was used, means police should question info gained from using CI