Memory

Memory - the mental processses involved in registering, storing and retrieving information.

Encoding - changing sensory input into a form that can be processed by the memory system.

Capacity - the amount of information that can be stored in memory at any particular time.

Duration - the length of time that information can be kept in memory.

Short-term Memory:

• Encoding - acoustic.
• Capacity - 7±2 items.
• Duration - 18seconds.

Long-term Memory:

• Encoding - semantic.
• Capacity - unlimited.
• Duration - up to a lifetime.

• Information is encoded visually into the sensory memory, which has a duration of 1-2 seconds and a capacity of 3-5items.  
• By paying attention to the information in the sensory memory, it is transferred to short-term memory.
• Information is encoded acoustically into short-term memory, which has a finite duration of 18seconds and a finite capacity of 7±2 items.
• Through rehearsal, information is transferred to long-term memory.
• If information is not rehearsed then it is likely that it will be lost through decay.
• Information is encoded semantically into long-term memory, which has an infinite duration and a capacity of up to a lifetime. 

Evaluation:

• Suggests that information has to rehearsed in order for in to be transferred into the long-term memory (LTM), however. people don't always rehearse information in real life situations and it is still processed into the LTM.
  • Rehearsal isn't always needed.
  • Some items can't be rehearsed.
    • Smells.
• The model is too simplistic.
  • Suggests that there is only one store short-term memory (STM) and LTM. However, braincase studies prove differently, showing that there are in fact multiple stores in the STM.
    • KF study - could process visual information but not verbal information.
  • Doesn't give an explanation as to how information from the LTM is used in the STM.
    • WMM explains this with the episodic buffer.
• Supporting studies:
  • Free recall; Glanzer and Cunitz (1996).
  • Encoding in LTM; Baddeley (1996) - primacy and regency effect.
  • Duration of LTM; Bahrick.
  • HM brain damage case study.

Central Executive:

• Controls attention.
• Controls subsidary systems.

Visual-spatial scratchpad:

• Holds information on form & colour.
• Deals with spatial and movement information.
• 'Inner eye'.

Phonological loop:

• Rehearses verbal inpit to prevent it from decaying (inner voice).
• Store fo accoustically encoded items (inner ear).

Episodic buffer:

• Temporary storage system.
• Allows information from the subsidary systems to combine with information from the LTM.

Evaluation:

• Explains our ability to carry out tasks by storing information briefly, ehilst actively processing it.
• Dual task technique; Baddeley and Hitch (1974).
  • When participants performed two tasks that used different subsidary systems, they could carry them both out easily.
  • When participants preformed two tasks that used the same subsidary system, they found it difficult to carry out both of the tasks and were slowed down.
  • Evidence of different components in the STM.
• KF brain damage study.
  • Could process visual information and meaningful sounds (visuo-spatial sratchpad intact).
  • Struggled with processing verbal information (phonological loop damaged).
• Central executive is an abstract concept that lacks proof of existence.
  • Capacity is unknown; we only know that it is limited.
  • Richardson (1984) argues that there are problems specifying the precise function of the central executive.
• WMM is limited to just the STM and doesn't say anything about LTM.

Misleading Information:

• Loftus and Palmer (1974).
  • Procedure:
    • Participants were shown a film of a car accident.
    • The participants were then asked "How fast were the cars going when they hit/collided/ smashed/bumped/contacted each other?
    • One week later, the participants were asked whether they had seen broken glass or not.
  • Findings:
    • Hit = 34miles.
    • Smashed = 41miles.
    • Word used to describe the accident affected the estimated speed.
    • "Smashed" group were more likely to say yes to broken glass, even though there was none.
  • Conclusion:
    • Leading questions can affect the accuracy of EWT and it has an influence on the person's repsonse.

• Evaluation:
  • Lab experiment.
    • Low ecological validity, as it cannot be generalised to the ouside world due to it being carried out in an artificial setting.
    • Watching a video is not as emotionally arrousing as a real life event. 
      • A later study found that partcipants gave a more accurate description of a robber when put in a robbery unware that it was staged.
    • High demand characteristics as the particpants may have become aware of the fact that the experiment was about leading questions, so they could have changed their behaviour.

Age of the Witness:

• Valentine and Coxon (1997).
  • Method:
    • 3 groups of participants (children, young adults and elderly people).
    • Watched a video of a kidnapping.
    • Then asked a series of leading and non-leading questions.
  • Findings:
    • Children and elderly were more likely to give incorrect answers to non-leading questions
    • Children were more likely to be misled by leading questions than adults or elderly.
  • Conclusion:
    • Age has an effect on the accuracy of EWT.
  • Evaluation:
    • Lacks ecological validity, as it was set in an artificial setting and wasn't as emotionally arousing as a real-life situation.

Cognitive interview:

• Geiselman et al (1986).
  • 89 students.
  • Participants were shown police training videos of violent crimes.
  • 48hours later, the students were interviewed individually by American law enforcement officers.
  • Interviewers either carried out standard or cognitive interviews.
  • Interviews were recorded and analysed for accuracy of recall.