Memory

• Coding


  The format in which information is stored in the various memory stores.
• Capacity


  The amount of information that can be held in memory
• Duration


  the length of time information can be held in memory
• Short term memory


  a limited-capacity memory store
• What is the coding of STM?


  acoustic
• What is the capacity of STM?


  5-9 items
• What is the duration of STM?


  18-30 seconds
• Long term memory


  the permanent memory store
• What is the coding of LTM?


  Mainly semantic
• What is the capacity of the LTM?


  unlimited
• Baddeley research on coding


  -Gave diff lists of words to 4 groups of ppts (acosutically/semantically similar or dissimilar)

  -Found that when told to recall immediately, they did worse on acoustically similar words and when recalled 20 minutes after, they did worse on semantically similar words

  - this shows information is coded semantically in the LTM
• Joseph Jacob digit span


  - the researcher gives e.g 4 digits, and the participant is asked to recall these in the correct order out loud.

  - if this is correct the researcher reads out 5 digits and so on until the pp cant recall correctly.

  - this determines the individuals digit span
• What mean digit span did Joseph Jacobs find?


  9.3 items
• What is chunking?


  grouping pieces of info together to improve encoding
• What did George Miller observe?


  - he noted that things come in sevens: 7 notes on the piano, 7 deadly sins

  and so on

  - this suggests that the span (or capacity) is STM is about 7 items
• Duration of STM - Margaret and Lloyd Peterson procedure


  - tested 24 undergraduate students with each taking part in 8 trials

  - on each trial the student was given a consonant syllable (or trigram) to remember and a 3 digit number

  - the student was then asked to count back from this number until told to stop to prevent any mental rehearsal of the consonant syllable

  - on each trial they were told to stop after a different amount of time: 3,6,9,12,15 or 18 seconds (called the retention interval)
• Duration of STM - Margaret and Lloyd Peterson results


  Their findings suggest that STM may have a very short duration unless we repeat something over and over again (verbal rehearsal)
• Duration of LTM (Bahrick et al) procedure


  - studied 392 pps from Ohio who were aged between 17 and 74

  - Their high school yearbooks we're obtained and recall was tested in various ways:

  1) photo recognition test consisting of 50 photos, some from the pps high school yearbook

  2) free recall test where pps recalled all the names of their graduating class
• Duration of LTM (Bahrick et al) results


  - pps tested the within 15 years of graduation were about 90% accurate in photo recognition

  - After 48 years, recall declined to about 70% for photo recognition

  - free recall was less good than recognition

  - after 15 years this was about 60% accurate, dropping to 30% after 48 years

  - this shows that LTM can last a long time
• Evaluation


  of coding, capacity and duration of memory-artificial stimuli

  -lacking validity

  - limitation of Miller's research is that we may have overestimated capacity of STM

  - meaningless stimuli in STM study:
• Evaluation


  of coding, capacity and duration of memory -artificial stimuli- Baddeley's study was quite artificial stimuli as the word lists had no personal meaning to pps.

  - This means we should be cautious about generalising the findings to different kinds of memory task.
• Evaluation


  of coding, capacity and duration of memory - lacking validity- limitation of Jacob's study is that it was conducted a long time ago and early research in psychology often lacks adequate control.

  - This would mean that results might not be valid because there were confounding variables not controlled
• Evaluation


  of coding, capacity and duration of memory - limitation of Miller's research is that we may have overestimated capacity of STM- limitation of Miller's research is that he may have overestimated the capacity of STM.

  - This suggests were the lower end of Miller's estimate is more appropriate than seven items
• Evaluation


  of coding, capacity and duration of memory - meaningless stimuli in STM study- in Petersons study the stimulus material was artificial and trying to memorise consonant syllables does not reflect most real life memory activities so this study has low external validity
• Multi store model


  - A representation of how memory works in terms of three stores called sensory register, short-term memory and long-term memory.

  - It also describes how information is transferred from one store to another, how it is remembered and how it is forgotten.
• Sensory register


  - The memory stores for each of our five senses, such as vision (iconic store) and hearing (echoic store).

  - Coding in the iconic sensory register is visual and in the echoic sensory register it is acoustic.

  - The capacity of sensory registers is huge (millions of receptors) and information lasts for a very short time (less than half a second).
• Who developed the multi store model?

  Atkinson and Shiffrin (1968)
• What does the multi store model describe?


  how information flows through the memory system
• What does the multi store model look like?


  - Information goes into our sensory register, if we pay attention it is transferred to our short-term memory.

  - In order to keep it here we have to rehearse it, if not it is forgotten.

  - If we elaborate on the information it can transfer to the long-term memory.

  
• What are the two main stores of the sensory register?


  iconic and echoic
• How is information coded in the iconic memory store?


  visual information is coded visually
• How is information coded in the echoic memory store?


  - sound/auditory information is coded acoustically
• What is the duration of the sensory register?


  Less than half a second
• What is the capacity of the sensory register?


  very high
• What is the short term memory known as?


  limited capacity store
• How does information have to be recalled from the LTM?


  - it has to be transferred back into STM by w process called retrieval

  - according to the MSM, This is true of all our memories
• Strengths of the multi-store memory model


  - research support from Baddeley

  
  

  - case study of HM
• Strengths of the multi store model - research support from Baddeley


  research support from Baddeley, that the STM and LTM are different and coded differently, they are clearly separate memory stores
• Strengths of the multi store model - HM


  - case study of HM, had his hippocampus removed which is the central memory function;

  - he could not form new long term memories, but he did have a strong STM

  - supporting how the LTM and STM are completely separate stores (must consider methodological issues of case studies)
• Limitations of the multi-store model


  -more than one type of STM

  
  

  - more than one type of LTM

  
  

  - artificial materials

  
  

  - Craik and Watkins