Memory

Memory

1. Coding, capacity and duration of memory

   • Coding
     • Alan Baddely: acoustically/ Semantic similar/ dissimilar words
       • LTM = Semantically
       • STM = Acoustically
       • limtiation: Articial stimuli instead of meaningful material = low external validity
   • Capacity
     • Digit Span
       • Joseph Jacobs: digit recalling until failure
         • Lacking validity: temporal validity and low internal validity
       • Mean span = 9.3 items OR 7.3 letters
     • Span on memory and chunking
       • George Miller observed everyday practices
         • capacity of STM is about 7 items (+-2)
         • CHUNKING: 5 words as well as 5 letters by grouping sets of digits or letters into chunks
         • Limitation: may have overestimated the capacity of STM - Cowan found four chunks only
   • Duration
     • STM: Peterson and Peterson tested 24 undergraduates. Trigram experiment
       • Short duration of 3-18 seconds
       • Limitation: material was articifical = low external validity and cannot relate to real world situations
     • LTM: Bahrick studied 392 ppts. High school year book experiment
       • Long time potentially forever
       • Strength: High external validity. Real-life meaningful memories were studied
       • Limitation: confounding vairiable struggle to be controlled

2. Multi-Store Model by Atkinson and Shiffrin

   • • Sensory Register: Senses input. ICONIC= visual. ECHOIC = sounds
     • Short Term Memory: Capcity of 7+-2. Coded acoustically and lasts about 30 seconds unless rehearsed
     • Long Term Memory: Unkown capacity, Lifetime memory and coded semantically
     • Strength: Supporting research evidence
     • Limitation: There is more than one type of STM- MSM is to simplistic
     • Strength: Triggered the start of further research
     • Limitation: Artificial material - supporting research conducted has low external validity

3. Types of long-term memory

   • Episodic memory: Our ability to recall events. 'Time-stamped'. complex single memory
   • Procedural Memory: Memory for actions, or skills. can unconsciously recall these.
   • Semantic Memory: Contains our knowledge of the world (E.G 2+2=4). contain concepts (E.G love)
   • Strength: HM and Clive wearing - both showed difficult recall of events but semantic was fine
   • Limitation: case studies = lack of control (E.G location of brain damage or personality variables) -> not generalisable

4. The Working Memory Model

   • • Central Executive: Monitors incoming data, makes decisions and allocates slave systems. Low storage capacity
     • Phonological loop: deals with auditory info. Divided into --> Phonological store, stores the words you hear & Articulatory process, inner ear
     • Visuo-spatial sketchpad: store visual and/or spatial info when required --> visual cache, visual data & inner scribe, records arrangement of objects
     • Episodic Buffer: Temporary store for information, integrating the visual, spatial and verbal into events (episodes) happening --> four chunk capacity
   • Strength: case studies - KF had brain damage, bad STM for verbal but could process visual = separate visual and acoustic stores
   • Limitation: lack of clarity over the central executive. doesn't explain anything. least understood & and needs to be clearly specified

5. Explanation for Forgetting: Interference

   • Types of interference
     • Proactive interference: Occurs when an older memory interferes with a newer one
     • Retroactive interference: happens when a newer memory interferes with an older one
     • Strength: real-life studies have supported the interference explanation. Rugby players asked to recall the names of teams they played --> Accurate recall didn't depend on how long ago the match was
   • McGeoch and McDonald, Effects of similarity
     • Procedure: ppts asked to remember a list of words, then asked to learn another set. Group 1: Synonyms, Group 2: Antonyms, Group 3: Unrelated, Group 4: Nonsense syllables, Group 5: Three-digit, Group 6: control
       • Findings: performance depended on nature of the second list. Synonyms produced worst recall. Three-digit numbers increased recall
   • Limitation: The artificial tasks makes interference much more likely in the lab. low external validity

6. Explanations for forgetting: Retrieval Failure

   • Encoding Specificity Principle
     • Endel Tulving (1983)
       • If a cue is to help us to recall info it has to be present at encoding and retrieval.
     • Context-dependant Forgetting
       • Godden and Baddley (1975)
         • Divers learning a list of words - underwater and on land
           • Accurate recall was 40% lower in the non-matching conditions.
     • State-dependant forgetting
       • Carter and Cassaday (1998)
         • Ppts learning a list of words - on drug OR of drug
           • Mismatch between internal state at learning and recall was worse
   • Strength: Supporting evidence, goes so far as to as to argue that retrieval failure is perhaps the main reason for forgetting from LTM. + external validity
   • Limitation: Baddeley - context effects are actually not very strong, especially in real life. different contexts have to be very different to see an effect