Memory

• Process of remembering

  1. Coding (or encoding)
  2. Storage
  3. Retrieval
• LTM and STM differ in terms of capacity, duration, and coding
• What is the capacity of STM?


  7 +/- 2 items
• What is the duration of STM?

  18-30 seconds
• How is STM coded?


  Acoustically
• What is the capacity of LTM?

  Unlimited
• What is the duration of LTM?

  Up to a lifetime
• How is LTM coded?

  Semantically
• What part of memory did Jacobs (1887) research?

  Capacity of STM
• Jacobs (1887)


  STM has a capacity of 9.3 digits and 7.3 letters

  There is a difference due to there only being 10 numbers while there are 26 letters so it’s more information to remember
• What part of memory did Miller (1956) study?

  Capacity of STM
• Miller (1956)


  People can remember 7 +/- 2 chunks of information. Capacity is 5-9 bits of information with an average of 7
• What part of memory did Peterson and Peterson (1959) study?

  Duration of STM
• What part of memory did Bahrick et al (1975) study?

  Duration of LTM
• Peterson and Peterson (1959)

  • 24 students were tested over 8 trails
  • They were given a consonant syllable and a three-digit number (e.g. THX 512)
  • They were asked to recall the consonant syllable after different intervals of time. During the intervals they had to count backwards from their 3-digit number
  • On average, 90% of participants were right after 3 seconds, 20% after 9, and 2% after 18
• Peterson and Peterson (1959) results

  After 3 seconds of counting backwards from their three-digit number, participants were right 90% of the time. After 9 seconds there were 20% of the time. After 18 seconds it was 2%.

  This suggestd that STM has a very short duration
• Bahrick et al (1975)

  • Tested 400 people of various ages (17-74) on their memory of classmates
  • A photo-recognition test consisted of 50 photos, some from the participants‘ high school yearbooks and they were asked to list the names they could remember
  • Participants who were tested within 15 years of graduation were 90% accurate. After 48 years they were 70% accurate. Free recall was about 60% accurate after 15 years, dropping to 30% after 48 years
• Bahrick et al (1975) findings


  Face recognition

  • 90% accurate 15 years after graduation
  • 70% accurate 48 years after graduation

  Free recall

  • 60% accurate 15 years after graduation
  • 30% accurate 48 years after graduation
• Coding


  The way information is changed so that it can be stored. Can be visual, semantic, or acoustic
• What part of memory did Baddely (1966) study?

  Coding
• Baddeley (1966)

  Argued coding of STM is mainly acoustic and coding of LTM is mainly semantic
• Evaluate research into STM

  • Capacity may be more limited than 7 +/- 2 - Cowan (2001) reviewed different studied and concluded that STM has a capacity of about 4 chunks
  • Artificial testing methods. May lack ecological validity
  • STM may not be exclusively acoustic - when presented with a visual task and prevented from verbally rehearsing, participants used visual coding in STM
• Research into LTM evaluation

  • May not be exclusively semantic - Frost (1972): long-term recall is linked to visual as well as semantic categories & some research has shown evidence of acoustic coding in LTM
• Atkinson and Shiffrin (1968)


  Multi-store model of memory
• Who proposed the multi-store model of memory?

  Atkinson and Shiffrin (1968)
• Multi-store model

  1. Sensory register
  2. Short-term memory
  3. Long-term memory
• What is the duration of the sensory register?

  Milliseconds
• How is information transferred from the environnement to the sensory register?

  Encoding
• How is information transferred from the sensory register to the STM?

  Attention
• How is information transferred from STM to LTM?

  Rehearsal
• How is information transferred from LTM to STM?

  Retrieval
• Why is information lost through the sensory register?

  If not attended to
• How is information lost through STM?

  Through decay and displacement if not rehearsed
• Multi-store model evaluation

  • Supporting evidence about the separation of STM and LTM from lab studies
  • Supporting case studies - Scoville and Milner (1985): H.M. had his hippocampus removed and after the surgery, he couldn’t form new memories
  • Criticised for being simplistic - WMM
  • LTM involves more than just maintenance rehearsal - Craik and Lockhart: long-term memories are created by the level of processing, not rehearsal
• Tulving (1985) argued that the multi-store model’s view of LTM was too simplistic
• Who suggested different type of LTM?

  Tulving (1985)
• Types of LTM

  Episodic, Semantic, and Procedural
• Categories of LTM, suggested by Tulving (1985)


  Explicit (knowing something) and implicit (knowing how to do something)
• Explicit memory


  Knowing something
• Implicit memory


  Knowing how to do something