memory according to atkinson and shiffrin

• define memory

  a store for mental representations of events, images, ideas and information after the original stimuli are no longer present
• what are the three processes involved in making a memory

  encoding

  storage

  retrival
• what is encoding


  transferring information from a sensory form into a form which can be processed

  - this is necessary for storage to occur
• types of encoding


  visual

  acoustic

  semantic

  
  

  (but can be any sense)
• what is storage

  where a memory is stored and retained, ready to be retrived

  - however this is no guarentee of retrival (just because something is stored does not mean it will be remembered)
• what are the two types of retrival

  recognition

  recall
• what is recognition (retrival)

  matching the available information to previously stored information
• what are the 3 types of recall (retrival)


  free recall

  cued recall

  serial recall
• what is free recall

  remembering information without any prompts
• what is cued recall


  remembering information with prompts
• what is serial recall


  no prompts and in the same order as it was learned
• what is the multistore model of memory

  created by atkinson and shiffrin in 1968

  
  

  starts with environmental stimuli

  - which enters the sensory register

  
  

  with attention paid to it

  transferres to the short term memory store

  - maintenance rehersal keeps it in the STMS

  - elabourative rehersal transferres it

  
  

  elab rehersal transferres it to LTM

  -info can be retrived into the STM from LTM
• what is the encoding of the sensory register

  sensory specific data
• what is the capacity of the sensory register

  limitless
• what is the duration of the sensory register

  approx 0.5s
• what is the encoding of the STM

  mainly acoustic
• what is the capacity of the STM

  7 (plus or minus 2) chunks
• what is the duration of the STM

  15-20s
• what is the encoding of the LTM

  mainly semantic
• what is the capacity of the LTM

  potentially unlimited, has been estimated at 1000GB
• what is the duration of the LTM

  up to a life time
• 3 evidences of atkinson and shiffrons version of SHORT TERM memory

  jacobs - capacity of the STM

  peterson and peterson - duration of STM

  baddeley - encoding in STM
• jacobs evidence of capacity in the STM (procedure)

  the capacity was tested by measuring the immediate digit span

  
  

  procedure:

  -list of random digits read out to all participants who had to repeat them back using serial recall

  - the list increased in length (starting at 3 digits) by one digit at a time until they couldnt recall

  -this was repeated a number of times

  -digit span was defined as the length at which participants were correct 50% of the time
• jacobs evidence of capacity in the STM (results and conc)


  he found the avg digit span was 9.3 with numbers and 7.3 for letters

  
  

  conclusion: STM has a limited capacity of around 5-9 items
• what is millers magic number

  7 (plus or minus 2) chunks of information, linking to the 5-9 items of jacobs

  
  

  he also found that chunking info together can increase the ammount of information stored
• peterson and petersons evidence for duration of STM (procedure)

  participants were shown a set of trigrams (combinations of 3 digits eg 4YP)

  
  

  -participants had to recall the trigrams after 3,6,9,12 or 18s

  -was repeated several times for each interval

  - between the presentation of the trigram and recall of it, participants were given a task to do in order to prevent rehearsal, the task was to count backwards from a 3 digit number

  -recall had to be 100% accurate and in correct order, serial recall
• peterson and petersons evidence for duration of STM (results and conc)

  recall was very good after a 3 second delay (80% correct) as the delay increased, correct recall decreased to the point that at 18 seconds there was only 10% correct recall

  
  

  conclusion:

  the duration of the STM is roughly 15-20s when rehearsal is prevented
• baddeleys evidence for encoding in the STM and LTM (procedure)

  participants were given four sets of words to learn

  - set A were acousticaly similar eg man,cap,can,cab,mad

  - set B were acoustically dissimilar eg pit,few,cow

  - set C were semantically similar eg great, large, big

  - set D were semantically dissimilar, good, huge, hot

  
  

  participants were asked to immediately recall the words the words and then asked to recall the words after a delay of 30s
• baddeleys evidence for encoding in the STM and LTM (results and conc)

  immediate recall (stm) showed that participants did less well on words that sounded alike (set A) than those that sounded diff (set B) they performed the same on set C and D

  
  

  conclusion:

  STM was used for recall, the coding is mainly acoustic because acoustically similar words were confused
• eval for jacobs, peterson and peterson, baddeleys experiments

  experiment type: lab (good as it can be controlled and measures what it is designed to measure, validity)

  
  

  experiment design: independant measures

  
  

  Demand characteristics

  P's may have guessed the aim of the experiment and behaved diff eg put more effort into remembering and more focus onto the stimuli material

  - has been replicated many times so it is unlikely

  
  

  low ecological validity

  -task is artificial and has no meaning to particips

  - may not be possible to apply results to real life
• 2 evidences of atkinson and shiffrons version of LONG TERM memory

  baddeley - encoding in LTM

  bahrick et al - duration of LTM
• baddeleys evidence of encoding in LTM (procedure)

  participants were given four sets of words to learn

  - set A were acousticaly similar eg man,cap,can,cab,mad

  - set B were acoustically dissimilar eg pit,few,cow

  - set C were semantically similar eg great, large, big

  - set D were semantically dissimilar, good, huge, hot

  
  

  participants were asked to immediately recall the words the words and then asked to recall the words after a delay of 30s
• baddeleys evidence of encoding in LTM (findings and conc)

  Best delayed recall (30s+): semantically dissimilar, they were distinct in the LTM

  
  

  Struggled with most: semantically similar, because they got muddled in the LTM

  
  

  Conclusion:

  The results suggest that encoding in the LTM is semantic because after a delayed recall, it was the semantically similar words that got confused (we remember things by meaning so if they are similar in meaning, they are easily muddled in the LTM and confused due to lack of different semantics)
• bahrick et als evidence of duration of LTM (procedure)

  participants were 400 ex high school students in the usa of various ages who were asked:

  - to free recall the names of any of those in their graduation class

  - to recognise former classmates from a set of 50 photos, only some of whom were former classmates

  
  

  independant measures design - not all people do all variables eg not waiting for people to age so it is quicker
• bahrick et als evidence of duration of LTM (findings and conc)

  photo recognition:

  - after 15 years, particips were 90% accurate at identifying faces

  - after 48 years, they were 70% accurate at identifying faces

  
  

  free recall of names:

  much less accurate

  - after 15 years, 60% accurate

  - after 48, 30% accurate

  
  

  conclusion:

  recognition is easier than recall, word recognition (from other vers of study) is better than picture recognition, the LTM has a very long potentially lifetime duration
• evaluation of bahrick et als duration of LTM study (negative :c)

  hard to generalise findings:

  -these are college friends who they wouldve had lots of contact with and much more time to 'rehearse' the knowledge of them and would have a greater emotional signitifcance

  -we may not have such long memories for less important info

  
  

  many extraneous variables:

  -they may still keep in contact with their college friends or get anual updates

  - they may have recently looked at an old class photo

  - onne may be famous
• evaluation of bahrick et als duration of LTM study (positive C:)

  high ecological validity:

  -definately testing real life memory as it is not artificial due to the fact that it is personal to the individual