Memory

Memory

1. Short term

   • Capacity- 7 + or - 2 chunks.
     • Millers Magic 7 using digit span technique. Lab- lacks ecological validity due to demand characteristics. No the same effort as real life & meaningless numbers.
   • Duration- 18-20 seconds. STM is an active process that stops if not rehearsed
     • Peterson&Peterson- 24 students 8 trials. consonant syllables and 3 digit numbers. Recall after intervals. 90% correct after 3 seconds, 2% correct after 18 seconds. Short verbal duration. Lab exp. = cause & effect & high internal validity. BUT artificial
   • Encoding- Acoustic. some semantically and visually
     • Baddeley- word lists semanticallyl similar words difficult but acoustic easier. ( cap, can, map). One to recall immediately and one after 20 mins. STM less acoustically similar, LTM less semantically similar. Lab study & lack ecological validity. Other studies show that visual coding may be substituted.
   • Long term
     • Capacity- unlimited
       • Infinity cannot be measured. LTM is never full. may deliberately remove info
     • Duration- mins-lifetime
       • Clive wearing- remembers piano but not wedding day. Skills last a lifetime but knowledge does not
     • Encoding- semantic (meanings) and visual (very well).
       • Remember meaning of convos but not details.

2. Multi-store model

   • Sensory register- where info is held at each of the senses. Capacity is large. Receives constant info but most receives no attention.
   • Attention- data is transferred into STM if attention is focused on it. First step in remembering
   • STM- info held here so it can be used for immediate tasks. New info can displace the old
   • Maintenance Rehearsal- repetition will keep info in STM then transfer to LTM. More times rehearsed, better it is remembered
   • LTM- potentially unlimited.
   • Retrieval- getting info from LTM, must pass back through STM
   • Baddeley, peterson & peterson show separate stores
   • Clive wearing- amnesia showed difference between STM and LTM. lived in 10-20 second world with 7+- 2 capacity. LTM worked for memories before illness e.g. piano.
   • More than one STM store. KF remembered non-verbal sounds but not verbal ones. More than one LTM store. Procedural, semantic and episodic. e.g. Clive had selective LTM
   • Rehearsal is not essential for LTM. some have no STM require LTM of after their brain damage. Too simplistic- cannot explain why we remember some things better or why recognition is better than recall even though rehearsal isn't used.

3. Working memory model

   • Baddley & Hitch (1974). Active model that explains how STM works (unitary)
   • Central executive- controls three slave systems. Decides what needs to be done and when. It has limited capacity and can choose to present or past input in LTM. It recalls info from LTM and starts rehearsal
   • Phonological loop- auditory store holds auditory info. Rehearses info to prevent loss and decay. 2 parts, phonological store--inner ear (hold words you hear) and articulatory--inner voice can rehearse sounds of up to 2 secs (maintenance rehearsal)
   • Visuo-spatial sketchpad- organises info visually. Visual and spatial info is temporarily stored here & divided into visual cache (items e.g. shapes) and inner scribe (what an object is and how much space is around it).
   • Episodic buffer- visual & acoustic with limited capacity. Integrates info from all over storages and records event. Sends info to LTM and explains how we remember coherent words better than random ones as we require info from LTM to process them
   • Baddley dual tasks- showed if we do two tasks at the same time that both use the same system then the performance will be low. Ppts 1 had to follow a moving light with a pointer and describe angles of the letter F and puts 2 followed the light and did a verbal task. Group 1 was difficult- shows separate stores for Visual and Verbal. But artificial.
   • Better than MSM as it describes what our brain does BUT does not say how it does it. e.g. little is said about hoe the central executive works. We know we can choose to attend to thing but doesn't say how we choose.
   • Brain scans- show different parts of the brain active. Evidence for the different components.
   • Relationship between WM and LTM is not clear. Not explain how memory is communicated with, draws info from and sends info to LTM.

4. Types of LTM

   • Procedural- knowing how. Not conscious recollection but shown through skills. Automatic as a result of practice e.g. piano
     • Cerebellum
   • Episodic- personal event. Specifics details, contextual details (weather) and emotions- conscious.
     • Hippocampus
   • Semantic- worldly & abstract shared knowledge. Relate to certain things e.g. social norms.
     • Temporal lobe
   • Tulving & brain scans- distinction between 3 types as different areas of the brain are active.
   • Distinction between procedural and declarative. HM brain damage after removing hippocampus to reduce epilepsy. Still form new procedural memories but nt declarative. e.g. learn raw figure but had no memory of learning this.
   • Weaknesses of case studies
   • It made be that episodic memories require greater processing and can be the gateway to semantic ones. Alzheimer patients can form new episodic but not semantic could be why. the knowledge can remembering your first swimming lesson could led to remembering knowing how to swim.

5. Exp. of forgetting: interference

   • Forgetting happens when a memory has disappeared or it unable to be retrieved.
   • Proactive interference- OLD disrupt NEW. Keppel & Underwood (1962) used Peterson & Peterson-- there was little or no forgetting of trigrams from the start of the procedure so can be explained in terms of PI. e.g. earlier memory of consonants was in LTM and interfering with memory for new consonants.
   • Retroactive interference- NEW disrupts OLD. Lap exp, group 1had 2 lists whereas group 2 had 1 list of paid words. All asked to recall first list & control group more accurate. Second list interfered with first.
   • Real world- Baddley & Hitch rugby players. Asked to recall names of teams played- some games missed due to injuries. Last game may have been last week or last month. Recall was equally good- shows incorrect recall was not due to decay but number of intervening games.
   • Adverts- both recall and recognition of adverts were impaired when ppts were exposed to 2 competing ads in the same week. = waste of money. Enhance memory by running multiple in one day = reduce interference.
   • Peterson & Peterson
   • Lab studies

6. Exp. of forgetting: retrieval failure

   • Where info exists in LTM but cannot be retrieved because of cues.
   • Encoding principle (ESP) Tulving & Pearlstone (1966).associate cues (mnemonics) are stored and retrieved at the same time as memories. Asked ppts to remember list of words belonging to different categories e.g. names of animals. Group 1 did free recall (40% recall), 2 given cues as category names (60% recall).
   • Context-dependent Godden & Baddley (1975). Deep sea divers.
   • State-dependent Goodwin (1969). Drunk or Sober 24hrs later.
   • Application – improves recall when you need to, eg. Exams – revise in a room where you will be taking your exams. Just thinking of the room where you originally learned was as effective as being in same room. Cognitive interview is effective – see evidence (recreating context).
   • Too simplistic – may be other reasons why forgetting occurs – eg. Interference theory (add evidence) and theory is difficult to disprove as if recall does not occur is it because the information is not stored or because you are not providing the right cue? (circular argument).

7. EWT: misleading info

   • Loftus and Palmer (1974) car crash & follow up. Lab exp 45 students. 'how fast when they crashed...smashed...bumped etc.' severe words led to faster estimates. 9mph difference.
     • 150 students 3 groups. critical question & week last asked if they saw smashed glass. faster they thought more likely to have seen smashed glass. = invert memory
       • Memories may have been contaminated through discussions. Study done in pairs watched same event with different details- more likely to incorrectly recall.
   • Lab pros & cons
   • Demand characteristics
   • Generalising (US students)
   • Loftus & Zanni (1975) difference between THE broken headlight and A broken headlight. supporting evidence, leading questions only have effect on more minor parts.

8. EWT: anxiety

   • Weapon focus effect theory- weapon distracts from criminal due to weapon anxiety. Johnson & Scott (1976) pen & knife lab. ppts to sit outside room & listen, one saw grease hand with pen (low anxiety) and the other saw gun (high anxiety). Identify man from 50 photos. group 1 49% accuracy, 2 was 33% accuracy.
     • Lab exp.
   • Christianson and Hubinette- robbery. Natural exp. testimonies from 58 out of 110 EW's to 22 bank robberies in Stockholm & interviewed 4-15 months after event. High accuracy of most EWT over time & better recall from closer witnesses (more anxious) shows anxiety gave better EWT and negative emotions last longer than neutral events.
     • natural exp. high ecological validity.
   • Supporting evidence- Yuille & Cutshall armed robbery Canada. Natural exp.
   • Real world applications- cognitive interview.

9. Cognitive interview

   • Fisher & Geiseln (1992) to get better quality of info & avoiding leading questions.
   • CR –Context Reinstatement Mentally- reinstate the context of the target event, RE - Report Everything Report every detail you can recall. Reconstructive memory applied. The theory is that reconstruction involves following retrieval paths to recall events. Repeating reconstructions and following different paths will produce new “memories”. Two cognitive interview techniques use these ideas: CP – Changed Perspective . RO – Recall in reverse order. Report the episode in reverse order
   • Made clear interviewer does not know anything of the event to reduce anxiety felt by witness, minimise distractions and allow to take time and not interrupt with leading questions.
   • Evidence from retrieval cues (to think about context and emotions)
   • Kohnken (1999) meta analysis 53 studies. 81% increase info but 61% inaccurate- more info but less accurate. but this done with uni students.
   • Time consuming & expensive so not common BUT Mermon found increased recall after 4hrs training
   • Geiselman (1999) children under 8 recall less with CI. some use only some of techniques so difficult to control variables

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