Models of Memory

Models of Memory

1. STM

   • Limited duration - 18 to 30 seconds unless maintenance rehearsal takes place
     • Peterson& Peterson
   • Limited capacity - 7 +/- 2 items. Can be increased by chunking
     • Jacobs
   • Acoustic encoding (sounds)
     • Baddeley

2. Multi - store model (Atkinson and Shiffrin 1968)

   • Information enters sensory Memory - there is a different sensory store for each sense (visual, hearing etc)
     • Only information attended to enters STM
   • Information is transferred from STM to LTM through rehearsal. Without rehearsal it is lost and the more rehearsed something is the stronger the memory trace
   • This model emphasises structures (the three stores) and processes (attention and rehearsal)
   • Positive evaluation
     • Differences in encoding (Baddeley) capacity (Jacobs) and duration(Peterson&Peterson for STM, Bahrick for LTM)
     • Recency effects (Glanzer and Cunitz's 1966) P's were presented with a lost of 18 words, they tend to remember the last few words because they are stored in their STM
     • Case studies of brain damaged patients
       • HM- Operation to remove the Hippocampus in the brain to relive his epilepsy which it did, but after the operation although his STM was still intact it affected the transfer from STM to LTM
       • *KF- Brain damage following a motorcycle accident, his STM digit span was still intact.
     • Interaction between STM and LTM is the chess player study - when pieces were arranged at random on the board there was no/little difference in pieces recalled between experts and novices however when arranged in set positions the experts recalled more than novices as their past experience of playing chess stored in their LTM
   • Negative evaluation
     • Rehearsal is not essential for the transfer to the LTM, emphasis on this may be due to artificiality of memory experiments. Highly emotive memory's seem to pass from the sensory memory to the LTM without rehearsal
     • STM and LTM are not single stores and its questionable whether they're separate. LTM is subdivided into episodic, declarative and procedural.
     • Active not a passive process. In order to chunk items in the STM it must use information from past experiences stored in our LTM
     • Over simplification suggesting STM and LTM stores may overlap
     • MSM doesn't take into account that memories are linked to emotions

3. Working memory model (Baddeley and Hitch 1974)

   • STM is an active store made up of three components
     • Articulatory phonological loop (acoustic memories)
     • Visuo spatial-sketchpad (visual memories)
     • Central executive (controls slave systems and categorises information into the right sub-store in the STM)
   • Positive evaluation
     • Hitch and baddeley (1976) - devised the dual task technique, the assumption being that if you can perform two tasks as well together as when you do them apart they must be using two different slave systems
     • Evidence for phonological loop - word length effect - P's were presented with two lists of words, in list one there were mono-syllable words and in list two there were poly - syllable. Its a repeated measures design where counter balancing was used. DV- number of words you recall IV- syllables in a word
     • Evidence for visuo - spatial sketchpad - P's were given a visual tracking task which involves keeping a pointer in contact with a moving dot of light. At the same time P's were asked to visualise the letter F and describe how to draw it to someone else
     • Evidence for central executive - inhibitory function e.g. stroop test. Central executive stops you reading the actual word
     • Practical application- research on working memory model can be applied to dyslexia - articulatory loop damaged, unable to sound out words so use visual techniques
     • WMM provides an advanced account of memory than the MSM because it explains better real life abilities- Baddeley started with asking 'what do we use our memory for' relating to everyday activities (KF case study*)
     • Ecological validity - applies to real life tasks
   • Negative evaluation
     • Lack understanding of key concepts (e.g. central executive) - main part of WMM yet we know least about it so more research needed
     • WMM is an over simplified account of memory as there is still much to be explained about the functioning of working memory
     • Does not fully explain how information transfers from working memory to long term memory

4. LTM

   • Encodes semantically
     • Baddeley (pen, pencil, notebook)
   • Unlimited capacity - 10 ish gigabytes information available but not always accessible
   • Duration - lifetime
     • Bahrick - high school recognition test

5. Encoding - way in which information is stored in your brain whether it is acoustic, visual, or semantic

6. Duration - How long information can we stored in your brain

7. Capacity - How much information can be stored in your brain