Memory

• Multi-store model of memory

  Proposed by Atkinson & Shiffrin (1968), suggests memory is made up of 3 components: sensory register, short-term memory, and long-term memory

  
• Sensory register


  • Unlimited capacity, very limited duration (less than 1 second), coding is raw/unprocessed information from 5 senses
• Short-term memory


  • Limited capacity (7 +/- 2 'chunks'), limited duration (20 seconds), coding is acoustic
• Long-term memory


  • Unlimited capacity, lifetime duration, coding is semantic (by meaning)

  
• Formation of memories


  Information passes sequentially from sensory register to short-term memory to long-term memory

  
• Organizing information into 'chunks' can extend the capacity of short-term memory
• If information is not rehearsed, it will not be transferred to long-term memory
• Long-term memory has an unlimited duration
• The multi-store model of memory has been extensively researched and provides support for the different components of the model
• Highly controlled study


  • Took place in a laboratory of Indiana University
  • High degree of control for extraneous variables
  • Procedure easy to replicate to test reliability
• Coding


  The way in which information is changed and stored in memory
• Capacity


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


  The length of time that information can be retained in a memory store
• Features of the multi-store model

  • Capacity: Sensory register - A, Short-term memory - 7 +/- 2, Long-term memory - Unlimited
  • Duration: Sensory register - C, Short-term memory - Approximately 20 seconds, Long-term memory - Lifetime
  • Coding: Sensory register - Raw (Unprocessed) / Modality Specific, Short-term memory - Acoustic, Long-term memory - D

  
• Atkinson & Shiffrin's (1968) multi-store model is often criticised for being too simplistic
• The Working Memory Model (WMM) proposed by Baddeley and Hitch (1974) divided STD into two separate subcomponents: the phonological loop and the visuo-spatial sketchpad

  
• Explicit (declarative) memories


  Include knowledge for events and facts (knowing that)
• Implicit (non-declarative) memories


  Skilled behaviours (knowing how), which are largely unconscious

  
• Episodic memory


  A type of explicit memory, which includes memories of personal experiences (episodes), such as your first day at school or when you last visited the doctor

  
• Episodic memories

  • Have three specific elements: details of the event, the context, and emotions, which are all interwoven to provide a single memory
  • The strength of episodic memories is determined by the strength of the emotions experienced when the memory is coded
  • A conscious effort is required to retrieve them
  • Associated with the hippocampus, although other areas of the brain regions are associated with coding (prefrontal cortex)

  
• Semantic memory


  A type of explicit memory, which includes memory for knowledge, facts, concepts and meaning about the world around us

  
• Semantic memories often start as episodic memories, as we acquire knowledge based on our personal experiences, but they are not 'time-stamped' in the same way nor do they remain closely associated with a particular event (episode)

  
• The strength of semantic memories is determined by the strength of the emotions experienced when the memory is coded, although semantic knowledge is often less personal in its nature and can relate to abstract concepts such as language and maths
• Semantic memories are generally stronger in comparison to episodic and are associated with the temporal lobe

  
• Explicit memory


  Memory for knowledge, facts, concepts and meaning about the world around us

  
• Semantic memories


  Often start as episodic memories, but are not 'time-stamped' and not closely associated with a particular event (episode)

  
• Semantic memories


  • Strength is determined by the strength of the emotions experienced when the memory is coded
  • Often less personal in nature and can relate to abstract concepts such as language and maths
  • Generally stronger in comparison to episodic memories
  • Associated with the temporal lobe

  
• Procedural memory


  Memory of how to perform certain tasks, actions or skills, such as swimming, reading and writing which have become 'automatic'

  
• Procedural memories


  • Implicit and therefore difficult to explain in words
  • Acquired through repetition and practice
  • Many formed early in life, e.g. walking
  • Associated with the cerebellum and motor cortex

  
• Types of long-term memory

  • Episodic
  • Semantic
  • Procedural

  
• Memory types

  • Explicit
  • Implicit
• Episodic memories


  Personal experiences
• Semantic memories

  Knowledge

  
• Procedural memories

  Performed tasks or skills
• Episodic memory

  Associated with the hippocampus
• Semantic memory


  Associated with the temporal lobe
• Procedural memory


  Associated with the cerebellum and motor cortex

  
• Brain scans provide support for the different types of long-term memory

  
• Research has shown that different parts of the brain are active when accessing episodic, semantic and procedural memory

  
• The case study of patient HM supports the distinction between implicit and explicit long-term memory