Memory

• Multi-store model of memory

  An information processing model of memory created by Atkinson and Shiffrin in 1968
• Multi-store model of memory

  • It is a linear model - information passes through it in one direction and has to go through each stage in order
  • It is a passive model - the stores simply hold information before passing it on or forgetting it
• Stores in the multi-store model

  • Sensory memory
  • Short-term memory (STM)
  • Long-term memory (LTM)
• Coding


  The format that information is held in
• Capacity


  How much information a store can hold
• Duration


  How long information is held in a store
• Information flow in the multi-store model

  1. Received from environment by senses

  2. Enters sensory memory

  3. Attention paid to information

  4. Moves to short-term memory

  5. Rehearsal to transfer to long-term memory
• Sensory memory


  • Modality specific - codes by sense organ
  • Huge capacity
  • Very short duration (0.25 seconds)
• Short-term memory (STM)


  • Acoustically coded
  • Capacity of 7 +/- 2 items
  • Duration of 18-30 seconds without rehearsal
• Long-term memory (LTM)


  • Semantically coded
  • Potentially unlimited capacity
  • Potentially unlimited duration
• Maintenance rehearsal


  Keeping information in STM while needed
• Elaborative rehearsal


  Linking new information to existing knowledge in LTM to transfer it
• The multi-store model is a relatively simple model of memory
• Research supporting the multi-store model

  • Glanzer and Cunitz's primacy-recency effect
  • Baddeley's acoustic vs semantic similarity studies
  • Jacobs' study on STM capacity
  • Peterson and Peterson's study on STM duration
• There is less research on the capacity and duration of LTM as it is difficult to test
• Artificial, unnatural tasks used in research

  Lack of ecological validity - findings may not apply to real-world memory use
• Artificial, unnatural tasks used in research

  Lack of mundane realism - participants may not be motivated like in real life
• The multi-store model is overly simplistic and does not fully capture the complexity of human memory
• The concept of rehearsal in the multi-store model is oversimplified
• Semantic memory


  Memory for facts and meanings, can be put into words
• Episodic memory


  Memory for personal experiences and events, can be put into words
• Procedural memory


  Memory for skills and actions, cannot be easily put into words
• Types of long-term memory

  • Semantic
  • Episodic
  • Procedural
• Semantic and episodic memories are declarative (can be put into words), procedural memory is non-declarative (cannot be easily put into words)
• Recalling semantic and episodic memories


  Requires conscious effort
• Recalling procedural memories


  Happens reflexively, without conscious effort
• Procedural memories


  • Highly resistant to forgetting
  • Almost impossible to forget
• Episodic memories


  • Somewhat easy to forget, especially if not emotionally important
• Semantic memories


  • More resistant to forgetting than episodic, but can still be forgotten
• Episodic memories are first coded in the prefrontal cortex and stored across the brain connected by the hippocampus
• Semantic memories are associated with the parahippocampal cortex and the temporal lobe
• Procedural memories involve the motor cortex and the cerebellum
• Case study of Clive Wearing


  • After brain damage, he retained semantic memories (knew he was married) but lost episodic memories (couldn't remember his wedding day), and retained procedural memories (could still play the piano)
• Amnesiac patients can improve on procedural skills like touch typing, but don't remember the episode or semantic memory associated with the skill
• Case studies and brain imaging research support the idea of distinct types of long-term memory
• There is some debate about whether the three types of long-term memory are truly distinct, as episodic and semantic memories are both declarative, and procedural memories may be connected to semantic memories