Capacity

• STM


  Jacobs

  A: to investigate how much information can be held in STM

  P: conducted in a lab

  presented ppts with random sequences of digits or letters

  then asked them to repeat them back in the same order, they were presented in

  started with 3 digits and increased until the ppt faced to reproduce the sequence successfully

  longest sequences length recalled correctly on 50% of trials was taken for the ppts STM span

  F: average STM span was between 5-9 items

  digits (9.3) were recalled better than letters (7.3)

  C: STM has a limited storage capacity

  the capacity of STM is determined by the size of the STM not the nature of the info
• STM Strength - Miller

  great historical importance - first significant findings of the capacity of STM

  practical applications - telephone numbers, post codes

  argued that the capacity of STM 7+-2

  nature of the stimulus presented is irrelevant so long as its chunked

  can use this as support for Jacobs (5-9 items)
• STM Weakness - individual differences

  e.g. IQ, age, profession/experience may have influenced results

  lacks mundane realism

  lab study - not real, an element of bias may exist
• LTM


  Luria reported the case of Solomon Shereshevsky whose memory was so perfect that he could remember virtually every detail of his life in the minutest detail.

  Luria studied him for 30yrs and gave him long lists of numbers, words and nonsense syllables to remember

  Luria found no limit to the capacity of Solomon's memory

  Standing et al - showed ppts 2560 pictures over a number of days

  when they were given a test of LTM they remembered 90% of the pictures
• STM Strengths


  lab - replicable due to controlled lab setting

  high internal validity - can establish cause and effect
• LTM Strengths


  case study - has mundane realism as you can't control the memory of the person

  highly detailed

  can prove ideas wrong - that LTM can last forever/is infinite
• STM Weaknesses


  lab - lacks mundane realism as the remembrance of pictures isn't really something occurring in real life

  lacks ecological validity as it's in a lab

  demand characteristics
• LTM Weaknesses


  case study - lack reliability - SH is a unique individual

  can't be replicated - only 1 person

  researcher bias - could form a relationship with the person