Cognitive Revision 2

Cognitive Revision 2

1. Atkinson & Shiffrin 1968: Modal Model of Memory

   • Sensory Stores
     • Iconic sensory store decays within 0.5 seconds
     • Echoic sensory store decays within 2-4 seconds and has a playback facility
   • STM
     • Internally represented info that is in a state of activation and can be accessed immediately
     • 7+/-2 capacity
     • Activated info in LTM is held in STM, but decay of activation causes info to leave STM
     • Rehearsal causes info to be retained in STM and therefore more likely to transfer to LTM
   • Displacement
     • Takes place if too much info is in the STM and additional items displace current items
     • Can be improved with chunking
   • Strengths
     • Stores differ in duration, capacity, forgetting mechanisms and effects of brain damage
   • Weaknesses
     • STM not only route to LTM
       • Unconscious learning occurs without ever occupying STM and neuropsychological evidence suggests it's more complex

2. Postman & Phillips 1965: Serial Position Curve

   • Primacy effect
     • The first few items on a list have a recall advantage due to being rehearsed
   • Recency effect
     • The last few items on a list are recalled due to being recent and are eliminated by a distractor task

3. Neuropsychological Evidence

   • Clive Wearing
     • Viral infection damaged medial temporal lobes
       • Unable to form new LTM, aware of memories for 30 seconds, H/E could remember words of songs
   • KF
     • Stroke leading to damage to left parietal lobe
       • Unable to store new STM, digit/letter span = two items or fewer, H/E LTM was normal
   • Independence of STM & LTM
     • Neuropsychological Double-Dissociations
       • Clive Wearing = impaired LTM but intact STM
       • KF = intact LTM but impaired STM for letters, words & digits
     • Prefrontal cortex necessary for control processes that contribute to STM & LTM performance

4. Baddeley & Hitch 1976: Working Memory Model

   • Experiment
     • Digit span task and verbal reasoning task
       • Task difficulty manipulated
         • Pts took longer to answer reasoning questions but no increase in errors
     • Hypothesis = verbal reasoning task uses central executive and digit span task uses phonological loop
   • Phonological Loop
     • Articulatory Suppression
       • Murrary 1967
         • Visual presentation of a sequence of digits, prevented sub-vocal rehearsal by uttering 'the' at audible level
           • Found performance poor
             • Prevents verbal re-coding of visually presented material into phonological store
     • Similarity Effect
       • Larsen, Baddeley & Andrade 2000
         • Recall 25% worse with a phonologically similar list compared to a dissimilar list
           • Confusion in phonological store
     • Neural basis: Henson, Burgess & Firth 2000
       • Phonological Store
         • Left inferior parietal cortex activity associated with phonological store
       • Articulatory Process
         • Left inferior frontal cortex activity associated with verbal rehearsal
   • Irrelevant Speech Effect
     • Salame & Baddeley 1982
       • Sequential visual presentation of 9 digits with condition 1 (spoken words) and condition 2 (nonsense syllables) and condition 3 (silent control)
         • Errors 40% higher in 1 and 2
           • Visual presentation requires verbal recoding, interference from concurrent speech
   • Word Length Effect
     • Retrieval worse for long words
       • Digit span greater in languages where digits are faster to articulate
         • Phonological loop with capacity of approx 1.5 seconds
   • Visuo-spatial Sketchpad
     • Temporary storage of spatial & visual info
     • Visual cashe stores visual form & colour info
     • Inner scribe processes spatial & movement info
     • Strengths
       • Supported by research showing independence in spatial & visual tasks
       • Support from studies of brain damaged patients
     • Weaknesses
       • Many tasks require both components
       • Not clear how info is combined
   • Central Executive
     • Focused attention
       • Ignore irrelevant info
     • Divided attention
       • Between two messages
     • Switching attention
       • Random generation of digits, switch between generating and checking randomness
   • Episodic Buffer
     • Limited capacity temporary storage system that is capable of intergrating info from variety of sources
   • Coding in LTM
     • Word list presented: acoustically similar, semantically similar and vice versa
       • Semantically similar = impaired LTM but acoustically similar had no affect
     • Nickerson 1965
       • Tested visual LTM using 600 pictures, tested recognition 1 day/1 year later
         • 1 day = 92%, 1 year 63%
   • Retrieval from LTM
     • Cue Dependency
       • Retrieval requires correct internal or external cue
     • Context Dependency
       • Retrieval better if environment at retrieval and encoding match
     • Dual process theory
       • Recollection (slower & requires attention), Familiarity (faster)

5. Declarative Memory

   • Episodic Memory
     • Storage & retrieval of specific events
   • Semantic Memory
     • General knowledge of objects, word meanings, facts and people
   • Explicit
     • LTM for facts and events that can be declared
     • Involves conscious recollection
   • Implicit
     • Reflected through changes in behaviour and procedural memory eg how to ride a bike
     • Doesn't involve conscious recollection
   • Tulving, Schacter & Stark 1982
     • List of multi-syllabled rare words eg toboggan
       • Tested implicit memory, 1 hour or 1 week later using 'Fragment Completion Task' - pts were unaware answers to 50% of the completions were in list 1
         • Repetition priming effect as there were more correct answers for items in list 1
           • Recognition was worse after 1 week than 1 hour
   • Cohen & Squire 1980
     • Reading mirror reversed script, text was reflected into a mirror
       • Improved with practice and there was increased reading speed
   • Graf, Squire & Mandler 1984
     • Part 1
       • Rate how much you liked words on word list
     • Part 2
       • Memory test
         • 3 explicit memory tests - free recall, recognition memory and cued recall
           • 1 implicit memory test - fragment completion
             • Amnesic pts worse on explicit but not implicit