Memory

• Multi-Store Model of Memory

  Proposed by Atkinson and Shiffrin (1968), describes how information flows through the memory system
• The Multi-Store Model (MSM) suggests that memory is made up of the sensory register (S), short-term memory (STM) and long-term memory (LTM)
• Formation of memories


  Information passes from one component to the next in a linear fashion
• Components of the MSM

  • Each component has specific type of coding, capacity and duration
• Coding


  The way in which information is encoded and stored in memory
• Duration


  The length of time that information is held in the memory store
• Capacity


  The amount of information that can be stored
• Sensory register


  • All stimuli from the environment pass into the sensory register, which comprises several modality-specific stores (e.g. iconic memory for visual, echoic memory for auditory)
• Duration of sensory register

  • Very brief, less than half a second (approximately 250 milliseconds)
• Capacity of sensory register

  • Very high, e.g. over one hundred million cells in one eye
• Attention


  Key process that determines whether information passes from the sensory register to short-term memory
• Short-term memory (STM)


  • Information is coded mainly acoustically, has limited duration of around 20 seconds, and limited capacity of 5-9 items
• Maintenance rehearsal


  Repeating material to oneself to keep it in STM
• Long-term memory (LTM)


  • Potentially permanent memory store for information that has been rehearsed for a prolonged period, information is coded semantically (in terms of meaning), and has unlimited capacity
• Retrieval from LTM


  Information has to be transferred back to STM before it can be recalled
• Research has provided support for the different components of the MSM
• Working Memory Model (WMM)

  Explanation of how short-term memory is organised and functions, proposed by Baddeley and Hitch (1974)
• Components of the WMM

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


  Supervisory system that monitors and allocates resources, has limited processing capacity
• Phonological loop


  • Deals with auditory information, has a capacity of about 2 seconds of speech
• Visuo-spatial sketchpad


  • Stores visual and spatial information, capacity of about 3-4 objects
• Episodic buffer


  • Temporary store that integrates information from other components, capacity of about 4 chunks, links working memory to long-term memory