Memory

• 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

  Wagner (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)
• Context-dependent forgetting


  Forgetting due to external cues available at learning not being available at recall
• State-dependent forgetting


  Forgetting due to internal cues available at learning not being available at recall
• Revising in the same room as the exam can help prevent context-dependent forgetting
• Context-dependent forgetting may only occur when the contexts are very different
• Context-dependent forgetting only affects memory when tested in certain ways, such as recall but not recognition
• Eyewitness testimony


  Evidence provided in court by a person who witnessed a crime, to identify the perpetrator
• Misleading information


  Information that alters an eyewitness's memory of a crime
• Leading questions


  Questions phrased in a way that suggests a certain answer
• Leading questions can significantly impact the accuracy of eyewitness testimony
• Post-event discussion


  When multiple eyewitnesses discuss what they saw, which can influence each individual's recall
• Post-event discussion can lead eyewitnesses to recall aspects of the crime they did not actually see
• Research into post-event discussion

  • Gabbert et al. (2003)
  • Studied participants in pairs
  • One participant in each pair watched a film of a crime, the other participant watched the same crime from a different angle
  • Discussion condition: Participants could discuss what they saw before recall test
  • Non-discussion condition: Participants could not discuss before recall test
  • 71% of discussion group recalled aspects they had not seen but picked up in discussion
  • Gabbert et al. concluded post-event discussion can significantly impact accuracy of EWT
• Research on the effect of anxiety on the accuracy of EWT is contradictory
• Evidence anxiety has negative effect on accuracy

  • Johnson & Scott (1976) found lower accuracy in high anxiety condition
  • Suggested weapon focus effect - eyewitnesses concentrate on weapon, not perpetrator
• Evidence anxiety has positive effect on accuracy


  • Christianson & Hubinette (1993) found victims with high anxiety had best recall
• Yerkes-Dodson Law


  Performance improves with anxiety up to an optimal point, then declines with further increases
• The Cognitive Interview 


  • Developed by Geiselman et al. (1984) to improve accuracy of EWT
  • 4 components: mental reinstatement of context, report everything, change order, change perspective
• Who looked into capacity of LTM

  Wagner
• Who looked into capacity of STM

  Miller - serial digit span method - chunking
• Who looked into the duration of STM

  Peterson - nonsense triagrams - X maintainance rehersal
• Primacy effect occurs because first words are rehearsed and transferred to LTM


  Recency effect occurs because last words are still in STM when recalled
• Does the SR have a large or limited capacity

  LARGE
• Central executive (CE)

  ·       The CE has a supervisory function

  ·       It is in overall control of working memory 

  ·       It has a limited capacity

  ·       It can process information from any sensory system

  ·       It directs information to the three slave systems (the phonological loop, the visuo-spatial sketchpad and the episodic buffer) and collects responses from them