Psychology- Memory

• Multi-store model of memory

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


  1. Receives raw sense information

  2. Attention passes information to short-term memory
• Short-term memory


  • Receives information from sensory register or long-term memory
  • Keeps information by maintenance rehearsal or passes to long-term memory
  • Coded acoustically
  • Duration approximately 18 seconds
  • Capacity 7 plus/minus 2 items
• Long-term memory


  • Very long duration, permanent storage
  • Theoretically unlimited capacity
  • Coded semantically
• Immediate recall was worse for acoustically similar words and recall up to 20 minutes was worse with semantically similar words
• Recall of a list of letters averaged 7 items, for numbers 9 items (Jacobs)
• Recall of a 3-letter trigram was less than 10 after 18 seconds with an interference task (Peterson and Peterson)
• Recall of school friends' names from photographs was 90% after 15 years, 80% after 48 years (Bahrick)
• Cognitive tests of models of memory are often highly artificial, low mundane realism, and conducted in lab environments, so findings may not generalise to everyday life
• Types of long-term memory

  • Declarative (explicit, conscious)
  • Non-declarative (implicit, unconscious)
• Episodic memory


  Memories of experiences and events, time-stamped, declarative
• Semantic memory


  Memory of facts, meanings, and knowledge, declarative
• Procedural memory


  Unconscious memories of skills, not declarative
• Patients with hippocampal damage had episodic amnesia but retained semantic memory (Vargha-Khadem)
• Clive Wearing had retrograde amnesia for episodic and semantic memories, but could gain new procedural memories
• Generalizing findings from idiographic case studies to explain memory in the wider population is problematic
• Working memory model


  An active processor made of multiple stores, replacing the short-term memory store in the multi-store model
• Working memory model components

  1. Central executive

  2. Phonological loop

  3. Visuospatial sketchpad

  4. Episodic buffer
• Performing two visual tasks or a visual and verbal task impaired performance, suggesting separate processing systems (Baddeley)
• Patient KF had selective impairment to verbal short-term memory but not visual functioning, suggesting separate subsystems (Shallice and Warrington)
• More prefrontal activation when integrating spatial and verbal information, suggesting the episodic buffer exists in the prefrontal cortex (Prabhakaran)
• Participants could recall more monosyllabic than polysyllabic words, suggesting the capacity of the phonological loop is time-based (Baddeley)
• The working memory model seems more accurate than the short-term memory component of the multi-store model, but issues remain with external validity and lack of mundane realism
• Explanations for forgetting


  • Interference (proactive, retroactive, similarity, time sensitivity)
  • Retrieval failure due to absence of cues (encoding specificity principle, context-dependent cues, state-dependent cues)
• Retroactive interference


  New information disrupts old information already stored
• Proactive interference


  Previously learned information causes confusion in the coding of later information
• Interference only explains forgetting when two sets of information are similar and one learned closer together in time
• Interference may not be a valid explanation for forgetting as it may only explain a temporary loss of information, not a permanent loss
• Post-event contamination


  Recollection of one witness alters the accuracy of another witness's recollection
• Anxiety


  A mental state of arousal that includes feelings of extreme concern and tension and physiological changes
• High anxiety levels


  May decrease recall due to weapons effect focus, but may also increase recall by improving alertness and awareness
• Yerkes-Dodson law of arousal

  Eyewitness testimony accuracy increases as anxiety rises, but a point is reached where too much stress results in lower accuracy
• Misleading information


  Leading questions influence recall
• Post-event discussion


  Witnesses change their eyewitness testimony to match other witnesses' accounts
• Lab-based research in eyewitness testimony that has no emotional impact on the participants can be argued to have low validity when applied to real eyewitness testimony
• Weapon focus


  Participants focus their attention on the weapon rather than the criminal, due to anxiety
• Research on the limitations of eyewitness testimony has led to real-life applications, such as the development of the cognitive interview
• Cognitive interview


  A technique designed to reduce the influence of schemas on the accuracy of recall
• The cognitive interview is time-consuming, requires significant training, and may not be adopted due to limited financial resources
• The cognitive interview is not effective in improving the recognition of suspects in identity parades and from photographs