memory

• Memory stores


  • Long term memory
  • Short term memory
• Coding


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


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


  Length of time information can be held in memory
• Short term memory


  • Limited capacity memory store
  • Coding is mainly acoustic
  • Capacity = 5-9 items on average
  • Duration = 18 - 30 seconds
• Long term memory


  • Permanent memory store
  • Coding is mainly semantic
  • Capacity = unlimited
  • Duration = up to a lifetime
• Memory stores


  • Long term memory
  • Short term memory
• Coding


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


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


  Length of time information can be held in memory
• Short term memory


  • Limited capacity memory store
  • Coding is mainly acoustic
  • Capacity = 5-9 items on average
  • Duration = 18 - 30 seconds
• Long term memory


  • Permanent memory store
  • Coding is mainly semantic
  • Capacity = unlimited
  • Duration = up to a lifetime
• 4 conditions


  • Group 1 - Acoustically similar
  • Group 2 - Acoustically dissimilar
  • Group 3 - Semantically similar
  • Group 4 - Semantically dissimilar
• Participants were shown original words

  Asked to recall in correct order
• Immediate recall (STM recall)


  Did worse with words that were acoustically similar
• Repeating back with 20 minute intervals (LTM recall)


  Did worse with words that were semantically similar
• Capacity


  Limit to the amount of information that our STM can contain at any one time
• Jacobs (1887) digit span


  • On average, could immediately recall 9.3 numbers and 7.3 letters in the correct order
• Duration


  The defining feature of STM
• Peterson and Peterson (1959)


  24 students given a constant syllable (PRX) and a 3 digit number to count backward for 3,6,9,12,15 or 18 seconds to prevent rehearsal
• 3 second interval


  80% correct recall
• 18 seconds


  3% recall
• Bahrick et al (1975)


  1. 392 americans aged between 17 and 74

  2. Recognition test from their high school yearbook photo

  3. Free recall from name of their graduation class
• Photobook recognition recall after 15 years


  90% accurate
• Photobook recognition recall after 48 years

  70% accurate
• Free recall after 15 years


  60% accurate
• Free recall after 48 years


  30% accurate
• Evaluations


  • Limitation of Baddeley's study - Didn't use meaningful material
  • Limitation of Jacobs study - Constructed a long time ago, poor control of extraneous variables
  • Limitation of Miller's research - May have overestimated the capacity of STM
  • Limitation of Peterson and Peterson - Artificial stimulus, random consonant syllables so external validity is low
  • Strength of Bahrick et al study - High external validity
• Sensory Register (SR)


  Sensory information coming from the senses is detected and recorded automatically. All information in STM and LTM were initially gathered by the SR. Information is passed on by paying attention.
• Sensory Register


  • Store depends on the sense organ that the information comes from (modality specific)
  • Very large capacity to contain all the sense impressions for all the senses in the moment
  • Only what is paid attention to is passed to the STM
  • Very short duration, as low as 250 milliseconds
• Short Term Memory (STM)

  Information in short term memory is stored acoustically (in the form of sound / spoken words)
• Short Term Memory


  • Miller suggested this is small, approximately 7 items plus or minus 2 items (5-9)
  • Can be improved by chunking, making small sets / groups of items
  • Short duration, 18-30 seconds
  • Duration of information can be extended by verbal rehearsal (rehearsal loop)
• Short Term Memory (STM)

  Through rehearsal passes information to the LTM. This is either maintenance rehearsal (repeating) or elaborative rehearsal (linking to information already in the LTM). Information is passed back from LTM with retrieval, and information can be lost via displacement (new info) or decay (lost over time).
• Short Term Memory (STM) Capacity

  • No limit has been found. Information can be lost, but this doesn't seem to be because it is "out of room" the information may still be in LTM but not accessible.
• Short Term Memory (STM) Duration


  • Is potentially unlimited as recall of childhood events is normal even for the oldest people.
• Cognitive experiments testing aspects of the MSM are often highly artificial, lacking in external validity
• There is low ecological validity, results collected in lab experiments may not be generalisable to other more naturalistic situations like school and work
• There is a lack of mundane realism, the experimental tasks testing the MSM are unlike how people use their memory in real life scenarios
• Procedural memory


  Part of the implicit long-term memory responsible for knowing how to do things, i.e. memory of motor skills
• Procedural memory does not involve conscious (i.e. it's unconscious - automatic) thought and is not declarative