types of memory

• there are three types of memory:

  • sensory register
  • short term memory
  • Long term memory
• Sensory register - temporarily stores information From our senses,

  disappears quickly unless pay attention to it through process of 'spontaneous decay'

  limited capacity and duration

  coded - depending on sense that it bring up
• The three types of memory all have differing:

  • duration - how long memory lasts
  • capacity - how much can be held in memory
  • coding - how information is stored
• short-term memory - limited capacity and duration

  coding is acoustic (sounds)
• Long-term memory - unlimited capacity and coding is semantic (by meaning)

  3 types of LTM:

  • Episodic memory - stores information about events that actually experienced
  • Semantic memory - stores facts and knowledge
  • procedural memory - stores knowledge of how to do things (walking)
• Capacity STM, Jacobs : method - participants given string of letters or digits had to memorise and repeat back same order. number of digits or letters increased until participant failed repeat correctly
• Capacity STM, Jacobs: results - participants able to recall 9 digits and 7 letters. increased with age

  Conclusion - STM capacity is between 7 and 9
• Capacity STM: Miller, created 7 +- 2 for capacity
• STM duration, Peterson and Peterson: Method - participants shown a trigram (BJQ) and asked them to recall after 3,6,9,12,15,18 seconds. During time they were asked to count back from a number as a 'interference task'
• STM duration, Peterson and Perterson: results - after 3 seconds participants recalled 80% of trigrams

  after 18 seconds participants recalled 10% of trigrams

  Findings - STM is 18 seconds unless repeat information
• Capacity LTM Bahrick et al (1975): method - studied 392 American participants of age 17-74. used yearbook photos from participants year in high school of real test

  tested 2 ways:

  • photo recognition - 50 photos some from participants high school
  • free recall test - recall all names off their graduating class
• Capacity LTM Barrack et al : findings - test 1 photo recall, 15 years of graduating 90% accurate, after 48 years or graduation recall 70% accurate

  test 2 free recall - 15 years of graduation 60% accurate, 48 year after graduation 30% accurate
• Capacity LTM Bahrick - duration of long-term memory lasts up to a lifetime
• Coding STM, Baddeley (1966): method - participants given 4 sets of words that were either:

  • acoustically similar (man, mad, mat)
  • acoustically dissimilar (pit cow bar)
  • semantically similar (big, large, huge,)
  • semantically dissimilar (good, hot, pig)

  used independent group design

  asked to recall the word either straight away or following a 20 minuet task
• Coding STM: results - participant had problems recalling acoustically similar words straight away (from STM)

  had problems with semantically similar word after break (LTM)
• Coding Baddely: results - STM acoustic coding

  LTM semantic coding