Memory

Memory

1. Multi-Store Model

   • Sensory Register
     • The memory stores for each of the 5 senses such as ionic and echoic. Large capacity but information only lasts less than half a second. Information will only ass into STM if attention is paid to it.
   • LTM
     • A memory has to be transferred back to STM to be recalled and the more a memory is rehearsed the longer it will last.
   • STM
     • Maintenance rehearsal is needed to keep information in STM, if kept long enough it will move to LTM. Fragile store information can be displaced by new information.
   • Strengths - Supporting evidence, Clive Wearing Case study. Weaknesses - More than one STM store (KF), More than one type of rehearsal, More than one type of LTM, too simplistic.

2. Eyewitness Testimony

   • Cognitive Interview
     • Strengths - Some elements more valuable than others means even if not used properly CI can still improve recall, Support Kohnken (1999) combined data from 50 studies. Weaknesses - Time consuming, Kohnken found increase in wrong information as well as correct information.
     • Fisher and Geiselman (1992) - !) Report everything, 2) Reinstate context 3) Reverse order 4) Change perspective.
     • Fisher et al (1987) enhanced cognitive interview, elements that focused on social dynamics such as eye contact.
   • Misleading Information
     • Leading Questions - In which the phrasing of the question implies a certain answer. Loftus and Palmer (1974) Participants watched filmed car accidents they were then asked a leading question in which the verb varied. "How fast were the cars going when they Hit/Collided/Bumped/Smashed/Contacted each other?". The verb Contacted resulted in a mean estimate of 31.8 mph and Smashed 40.5 mph. Also a second experiment was carrie bout in which participants were asked if they saw broken glass even though there wasn't any, those who heard smashed were more likely to say they had seen broken glass than those who heard hit.
     • Post Event Discussion - when two witnesses discuss an event the testimonies will become contaminated because information form other witnesses will get combined. Gabbert et al (2003) participants were placed in pairs and watched the same crime from a different POV, Afterwards they discussed what they had seen before being asked to recall. 71% of participants mistakenly recalled aspects of the event they did not see..
     • Strengths - RLA, investigations and the use of EWT in prosecution. Weaknesses - Artificial tasks, videos do not provide the same experience as real life. Individual differences, some people will go along with the flow more. Demand Characteristics, with yes/no questions people are more likely to say yes as it seems more helpful.
   • Anxiety
     • Yerks and Dodson (1908) described the relationship between anxiety and accurate recall as an inverted U.
     • Weaknesses - Weapon focus may be irrelevant as participants focus on the item our to surprise rather than anxiety, Field studies lack control, Ethical issues with creating anxiety in participants, Inverted U too simplistic as anxiety is difficult to define and measure accurately.
     • Positive Effect - Vuille and Cutshall (1986) study of a real life shooting in which interviews conducted 4-5 months later were compared with the original police interviews, participants were also asked to asses their anxiety at the time. Participants who reported higher anxiety levels were more accurate 88% compared to 75%.
     • Negative Effect - Johnson and Scott (1976) effect of weapons on recall. Led participants to believe they were waiting to take part in a study, they then herd an argument and either saw someone walk out with a pen or heard broken glass and saw someone walk out with a knife covered in blood. When asked to identify the person 49% in the low anxiety condition could compared to 33% in the high anxiety condition.

3. Working Memory Model

   • Central Executive
     • Coordinates Sub-Systems and allocates processing resources.
   • Phonological Loop
     • Processes information in terms of sound, coding is acoustic. Consists of the Phonological Store, which stores the words you hear, and the Articulatory Process, which allows maintenance rehearsal, capacity is believed to be about 2 seconds worth or speech,
   • Visuo-Spatial Sketchpad
     • Processes visual and spatial information, according to Baddeley capacity is 3-4 objects. Logie (1995) subdivided the VSS into Visual Cache, which stores visual data, and the Inner Scribe, which records the arrangement or objects in a visual field.
   • Episodic Buffer
     • Brings together material from other stores into one memory, also provides a bridge to LTM.
   • Strengths - Clinical Evidence by Shallice and Warrington who studied KF, who could process visual information but not verbal. Dual task, Baddeley et al (1975) showed participants had more difficulty carrying out two similar tasks than different ones. Word Length studies support the phonological loop. Weaknesses - Lack of clarity over the CE, doesn't explain anything and is not well understood so WMM is not fully explained.

4. Explanations For Forgetting

   • Interference
     • McGeoch and McDonald (1931) - Studied retroactive interference by giving participants a list of words to remember and then a second list that varied in similarity. Participants who had the most similar second list preformed worse during recall whereas those who had the least similar second list preformed the best.
     • Strengths - Lab evidence, resulting in strong reliability. Real life Study, Rugby player and their games. Weaknesses - Artificial materials, Time between learning and recalling memory is short which is not representative of how memories are really recalled.
     • Retroactive Interference - forgetting occurs when newer memories disrupt the recall of older memories, the degree of forgetting is greater when the memories are similar.
     • Proactive Interference - forgetting occurs when older memories disrupt the recall of newer memories, the degree of forgetting is greater when the memories are similar.
   • Retrieval Failure
     • Context-Dependant Forgetting - Godden and Baddeley (1975) 4 conditions in which participants learnt and recalled a set of words. Words were either learnt on land or underwater and then either recalled on land or underwater. In the conditions that matched recall was 40% better as the external cues matched.
       • Encoding Specificity Principle - Tulving (1983) researched retrieval failure and summarised that if a cue is used to recall information it must be present at encoding and retrieval.
     • State-Dependant Forgetting - Carter and Cassaday (1998) had 4 condition but instead or on land or under water the participants were either on an antihistamine or not. Again in the conditions that matched recall was better as internal cues were the same.
     • Strengths - Supporting evidence which increases validity, RLA basic principle of eyewitness testimony. Weaknesses - Context effects usually not that strong as environments are rarely as different. Underwater test done again but with a recognition test and there was no defence in recall suggesting it depends on the type of memory tested. EPS not testable.

5. Types Of LTM

   • Episodic
     • For personal events, memories from here have to be retrieved consciously and with effort. Complex as they are time stamped and each memory includes several elements.
   • Semantic
     • Knowledge of the world, memories from here also have to be recalled deliberately. Not time stamped and less personal than episodic, however it is constantly being added to.
   • Procedural
     • Knowledge of how to do things, memories of learnedd skills usually recalled without making a conscious effort.
   • Evaluation
     • Strengths - Clinical Evidence from HM and Clive Wearing only damage to episodic memories. Neuroimaging Evidence Tulving et al (1994) Scanned brains while doing various tasks and found episodic and semantic are from the prefrontal cortex, right and left respectively. Real Life Application, allows identification of aspects of LTM and better lives as Belleville et al (2006) showed episodic memories can be improved in older people with mild cognitive impairments.
     • Weaknesses - Clinical Evidence Cannot be Generalised, Cohen and Squire (1980) disagreed with Tulvings findings and argued that episodic and semantic memories were store in the same place as declarative memory.

6. Coding, Capacity & Duration

   • Capacity
     • The amount of information that can be held in a memory store. Digit Span (Jacobs 1887) mean span was 9.3 items and 7.3 letters. Span and chunking (Miller 1956) noted things come in sevens so suggested this was the capacity of STM, also noted that people could remember more if they grouped items.
       • Miller - There is contradicting evidence that suggests he overestimated, Cowan 2001 suggested capacity was only about 4 chunks.
       • Jacobs - Research is old meaning there is uncertainty about the control and thus the validity of the findings. However results have been confirmed in other studies which support the validity.
   • Coding
     • The format in which information is stored in the various memory stores, Baddeley showed different groups lists of words that were with acoustically or semantically similar or dissimilar. It was found that if asked immediately participants did worse with acoustically similar words but if asked 20 minutes later they did worse with semantically similar words. Brandimote (1992) and Frost (1972) also found that visual coding is used in STM and LTM.
       • Baddeley - Artificial materials that had no meaning so therefore means the finings are difficult to generalise.
   • Duration
     • The length of time information can be held in a memory store. STM (Peterson and Peterson 1959) used trigrams and 3 digit numbers that prevent rehearsal, time they had to remember varied, found STM duration was 18-30 seconds. LTM (Bahrick 1975) used school yearbooks to do a photo recognition and free recall test, those tested with 15 years were 90% and 60% accurate in the two tests and after 48 years 70% and 30%. LTM (Shepherd 1967) 612 memorable pictures after an hour almost perfect recognition and after 4 months participants were still able to recognise 50%.
       • Shepherd - Images used were meaningless to the participants so were not representative of real life memories.
       • Bahrick - High external validity as the memories tester were personal and had meaning, However there are CV's as participants are likely to have looked at their yearbooks since getting them.
       • Peterson and Peterson - Meaningless stimuli and artificial material which is not representative of real life memories so lacks external validity.