Memory

• Multistore model of memory


  Atkinson and Shiffrin 1968, a theoretical cognitive model of how the memory system processes information
• Short-term memory


  1. Receives info from the 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 seven plus or minus 2 items
• Long-term memory


  1. Very long duration, permanent memory storage

  2. Theoretically unlimited capacity

  3. Forgotten information appears to just be inaccessible

  4. Coded semantically in the form of meaning

  5. Must be passed back to short-term memory to use the information
• 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 the rows were stored in sensory register
• 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 for critical details after 1 year, 45% after 5 years (Wagner)
• Duration of long-term memory

  90% recall of school friends' names from photographs after 15 years, 80% after 48 years (Bahrick)
• Cognitive tests of models of memory like the multistore model are often highly artificial, low in mundane realism, and conducted in lab environments, so the findings may not generalize 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)
• Children with damage to the hippocampus but not the parahippocampal cortex had episodic amnesia but attended school, spoke, and learned facts (semantic memory), suggesting semantic and episodic memory use different brain regions
• Clive Wearing has retrograde amnesia for episodic memories but can still remember facts about his life (semantic memory) and gain new procedural memories, suggesting the different types of long-term memory are separate and use different brain areas
• Generalizing the findings of idiographic clinical case studies to explain how memory works in the wider population is problematic, as other unknown issues could be unique to that individual
• 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 much better when the tasks do not use the same processing, suggesting the phonological loop and visuospatial sketchpad are separate systems
• 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 located in separate brain regions
• 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 studies often lack mundane realism and may not generalize to how we use memory in day-to-day life
• 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 processes of memory described in models like the working memory model, so inferences and assumptions must be made that could be incorrect
• Interference theory of forgetting

  • Proactive interference (old information disrupts new)
  • Retroactive interference (new information disrupts old)
  • Similarity interference (more likely when information is similar)
  • Time sensitivity interference (less likely with larger gaps between learning and retrieval)
• Retrieval failure due to absence of cues

  • Q-dependent forgetting (information is in long-term memory but forgotten due to lack of appropriate cues)
  • Context-dependent cues (aspects of external environment act as cues)
  • State-dependent cues (aspects of internal environment act as cues)
• 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
• State dependent cues


  Aspects of our internal environment that work as cues to memory
• 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, the lack of organization cues inhibits memory
• Retroactive interference


  • Adding new street names to memory makes recalling old street names harder
• Proactive interference


  • Previously learned word combinations cause confusion in the coding of later word lists
• Interference may only explain a temporary loss of information, not a permanent loss
• Memory is not an accurate recording of events, it's reconstructed in recalling
• Schemas influence leading questions that imply a particular answer, this can influence how memory is recalled
• The recall of events by one witness alters the accuracy of another witness's recollection
• High anxiety levels may decrease recall due to weapons effect focus, but may also increase recall by improving alertness and awareness
• Leading questions influence recall, the more extreme the verb the faster the estimation of speed