Memory

• The multi-store model (MSM) was proposed by Atkinson & Shiffrin (1968)
• Multi-store model


  Characterises memory as the flow of information through a system of three stores: the sensory register, short-term memory, and long-term memory
• Sensory register, short-term memory, long-term memory

  • Each store differs in terms of coding, capacity, and duration
• Sensory register (SR)


  Information gathered by the senses enters the SR
• Sensory stores in the SR


  • Iconic store (visual information)
  • Echoic store (auditory information)
• Information that is paid attention to passes on to short-term memory
• Coding in SR


  Information is in a raw and unprocessed form, not coded
• Capacity of SR


  Large, constantly bombarded with information
• Duration of SR


  Limited, information fades away after a few seconds if not paid attention to
• Short-term memory (STM)


  Stores information received from the SR
• Coding in STM


  Mainly coded acoustically, information tends to be stored and represented through sound
• Research into coding in STM

  Baddeley (1966) divided participants into two groups, one heard acoustically similar words and the other heard acoustically dissimilar words, participants found it more difficult to recall the acoustically similar words, Baddeley concluded that STM codes acoustically
• Capacity of STM


  Limited, information can be forgotten through displacement (old information pushed out by new)
• Chunking


  Grouping information into larger meaningful units to increase the capacity of STM
• Research into the capacity of STM


  Miller (1956) used the serial digit span method, found most participants could recall 7 +/- 2 chunks of information
• Duration of STM


  Limited, information can be forgotten through decay (fading away over time)
• Maintenance rehearsal


  Repeating information to increase the duration of STM, largely verbal as STM is coded acoustically
• Research into the duration of STM

  Peterson & Peterson (1959) presented nonsense trigrams, found 90% recalled correctly after 3 seconds but only 5% after 18 seconds, concluded STM duration is 20-30 seconds
• Long-term memory (LTM)


  Stores information received from STM, information is retrieved from LTM back to STM for use
• Coding in LTM


  Mainly coded semantically, information tends to be stored and represented through meaning
• Research into coding in LTM

  Baddeley (1966) divided participants into groups, one heard semantically similar words and the other semantically dissimilar, participants found it more difficult to recall semantically similar words, Baddeley concluded LTM codes semantically
• Capacity of LTM


  Potentially unlimited
• Research into the capacity of LTM

  Wagenar (1986) created a diary of over 2400 events over 6 years and had excellent recall, concluded LTM capacity is potentially unlimited
• Duration of LTM


  Potentially unlimited, information does not need continuous rehearsal to be maintained, but can still be forgotten through decay
• Research into the duration of LTM

  Bahrick et al. (1975) found participants could identify faces from their high school yearbook with 70% accuracy 48 years later, concluded LTM duration is potentially unlimited
• The serial position effect supports the idea that STM and LTM are separate stores
• Case studies of brain-damaged patients like HM support the idea that STM and LTM are separate stores
• The role of maintenance rehearsal in transferring information from STM to LTM has been criticised, as long-term memories can form without rehearsal (e.g. flashbulb memories)
• Evidence suggests STM is not a unitary store, it has visual and auditory components (e.g. case of KF)
• The working memory model (WMM) was proposed by Baddeley & Hitch (1974)
• Working memory model


  Suggests information in STM is processed (worked on) whilst being stored, and replaces the idea of a unitary STM with multiple components
• Components of the WMM

  • Central executive, phonological loop, visuo-spatial sketchpad, episodic buffer
• Central executive


  • Supervisory function in overall control of working memory, limited capacity, can process information from any sensory system
• Phonological loop


  Temporarily stores and processes auditory information, divided into phonological store and articulatory control process
• Visuo-spatial sketchpad


  Temporarily stores and processes visual and spatial information, divided into visual cache and inner scribe
• Episodic buffer


  Extra storage system that integrates information from the other components
• Evidence for the WMM from dual task studies

  Baddeley et al. (1975) found participants could complete visual and verbal tasks simultaneously, supporting separate visual and auditory components
• Evidence for the WMM from case studies

  Case of KF supports separate visual and auditory components as his verbal STM was impaired but visual STM was intact
• Dual task studies lack ecological validity as the tasks are often artificial
• Case studies lack generalisability as each case is unique