psychology-memory

• Multistore model of memory


  Atkinson and Shiffrin 1968, a theoretical cognitive model of how the memory system processes information
• Sensory register


  1. Receives raw sense impressions

  2. Attention passes info to short-term memory

  3. Coding is modality specific

  4. Capacity is very large

  5. Duration is very short (250 milliseconds)
• Short-term memory


  1. Receives info from sensory register by paying attention or from long-term memory by retrieval

  2. Keeps information by repeating maintenance rehearsal or passing to long-term memory

  3. Coding is acoustic

  4. Duration is approximately 18 seconds

  5. Capacity is 7 plus/minus 2 items
• Long-term memory


  1. Very long duration, permanent memory storage

  2. Theoretically unlimited capacity

  3. Coded semantically in the form of meaning

  4. Information must be passed back to short-term memory to be used
• Words at the start and end of word lists were more easily recalled (Primacy and recency effect)
• Recall of a random row of a 12x12 grid flashed for 1/120th of a second was 75%, suggesting all rows were stored in sensory register but forgotten too quickly
• Immediate recall was worse for acoustically similar words and recall after 20 minutes was worse for semantically similar words, suggesting short-term memory is coded acoustically and long-term memory is coded semantically
• Capacity of short-term memory

  Average 7 items for letters, 9 for numbers (Jacobs)
• Duration of short-term memory

  Less than 10% recall of a 3-letter trigram after 18 seconds with an interference task (Peterson and Peterson)
• Capacity of long-term memory

  75% recall of critical details after 1 year, 45% after 5 years (Wagner's diary study)
• Duration of long-term memory

  90% recall of school friends' names after 15 years, 80% after 48 years (Bahrick)
• Cognitive tests of memory like the multistore model are often highly artificial, low in mundane realism, and conducted in lab environments, so findings may not generalise to real-world memory use
• Types of long-term memory

  • Declarative (explicit, conscious)
  • Non-declarative (implicit, unconscious)
  • Episodic (experiences and events)
  • Semantic (facts and knowledge)
  • Procedural (skills and habits)
• Patients with hippocampal damage had episodic amnesia but intact semantic memory, suggesting they use different brain regions (Vargha-Khadem)
• Clive Wearing had retrograde amnesia for episodic and semantic memories, but could gain new procedural memories through repetition, suggesting the memory types use different brain areas
• Generalizing findings from idiographic case studies to explain memory in the wider population is problematic, as unique individual factors may explain the behaviour
• Working memory model


  Baddeley and Hitch 1974, a theoretical counter model of information processing that replaced the short-term memory store in the multistore model
• Working memory model components

  1. Central executive (controls attention and filters information)

  2. Phonological loop (processes sound information)

  3. Visuospatial sketchpad (processes visual and spatial information)

  4. Episodic buffer (general store to hold and combine information)
• Performing two visual tasks or a visual and verbal task simultaneously is better when they use separate processing, suggesting the phonological loop and visuospatial sketchpad are separate systems (Baddeley)
• Brain injury patient KF had selective impairment to verbal short-term memory but not visual functioning, suggesting the phonological loop and visuospatial sketchpad are separate processes in the brain (Shallice and Warrington)
• The working memory model seems more accurate than the short-term memory component of the multistore model in describing how memory is used as an active processor
• Memory tasks used in research often lack mundane realism and may not generalise to real-world memory use
• The central executive concept in the working memory model needs further development, and the inclusion of the episodic buffer is part of this
• It is impossible to directly observe the memory processes described in models like the working memory model, so inferences and assumptions must be made that could be incorrect
• Interference theory


  We forget because long-term memories become confused or disrupted by other information
• Types of interference


  • Proactive interference (old information disrupts new)
  • Retroactive interference (new information disrupts old)
  • Similarity interference (more likely with similar information)
  • Time sensitivity interference (less likely with longer time gaps)
• Retrieval failure due to absence of cues


  Information is in long-term memory but forgotten due to lack of appropriate prompts or context
• Encoding specificity principle


  Context-dependent cues (external environment) and state-dependent cues (internal state) act as prompts to retrieve memories
• Retroactive interference


  New information disrupts old information
• Proactive interference


  Previously learned information disrupts the learning of new information
• Interference only explains forgetting when two sets of information are similar and one learned closer together in time
• Context dependent cues


  Aspects of our external environment that work as cues to memory, such as sight, sound, and smells
• State dependent cues


  Aspects of our internal environment that work as cues to memory, such as emotions, drugs, and states of arousal
• Category or organizational dependent cues


  Providing cues that relate to the organization or category of memories
• The most effective cues have fewer things associated with them, and the lack of organization cues inhibits memory
• Retroactive interference


  • Smith sent a questionnaire to 11 to 79 year olds, including a map of the area around their school without street names, and found that the more times an individual moved home, the fewer street names could be recalled, suggesting adding new street names to memory makes recalling old street names harder
• Proactive interference


  • Greenberg and Underwood found that the number of correctly recalled word pairs decreased the more word pairs had been learned previously, suggesting the previously learned word combinations cause confusion in the coding of the later word lists
• Interference may only explain a temporary loss of information, not a permanent loss, and may not be a valid explanation for forgetting
• Reconstructive memory


  • Memory is not an accurate recording of events, it's reconstructed in recalling, and may produce errors and confabulations
• Schemas


  Influence how memory is recalled, either due to an actual change to the memory (substitution bias) or due to an emotional pressure to give a particular response (response bias)