cognitive: MSM AND WMM

• Sensory memory can hold information for about 0.5 seconds before it decays
• Short-term memory


  • Capacity is between 3 and 7 items
  • Information can be held for up to 30 seconds
  • Information is transferred to long-term memory through rehearsal
• Information in long-term memory does not affect short-term memory, information flows one direction only from short-term to long-term memory
• Long-term memory

  • Encodes information semantically and temporally
  • Has a potentially unlimited capacity
• Information can be forgotten from long-term memory due to interference or failure to retrieve it
• Research on short-term memory

  1. Peterson and Peterson (1959) used an interference task to stop rehearsal

  2. Recall dropped rapidly after 15-18 seconds, suggesting decay in short-term store
• Atkinson & Schiffrin's Multistore Model of Memory

  • Supported by case studies of brain damaged patients
  • Supported by primacy-recency effect
  • Weakened by research showing rehearsal does not necessarily transfer to long-term memory
  • Weakened by research showing long-term memory can influence short-term memory
• Laboratory experiments are often used to provide supporting evidence for the multistore model, but this can be a weakness due to the artificial nature of the tasks
• The multistore model has practical applications in education, such as the use of rehearsal in revision
• Working memory


  Different systems for different types of information
• Components of the working memory model


  • Central executive
  • Phonological loop
  • Visuospatial sketchpad
• Central executive


  • Deals with the running of the memory system, decides what information to pay attention to and what to ignore, allocates information to the slave systems, deals with cognitive tasks such as problem solving, relates information to long term memory
• Phonological loop


  Stores and processes spoken and written information, has a phonological store (inner ear) that holds temporary sound information, and an articulatory rehearsal system (inner voice) that rehearses and stores verbal information
• Visuospatial sketchpad (VSSP)

  Stores and processes visual and spatial information, plays a role in navigation and avoiding obstacles, displays and manipulates visual and spatial information from long-term memory
• Evidence from case studies supports the WMM. This is shown in the case study of K.F. (Shalice & Warrington, 1974). KF, suffered impaired STM after a motorcycle accident which damaged his parietal lobe. He had a digit span of 1[suggesting impairment to phonological store), but he had an intact visual store. This supports the theory that WM has separate subsystems.
• Laboratory experiments


  • Standardised procedures which means that they can be replicated in different circumstances
  • Researcher is able to manipulate the independent variable and seeing how it impacts on the dependent variable, allowing us to infer cause and effect
  • Increases the scientific credibility of the theory
• Baddeley's research


  • Investigates the effect of acoustic and semantic similarity on memory for word sequences
• Use of laboratory experiments to investigate working memory model


  Can also be viewed as a weakness
• Artificial tasks (tracing a letter F while tracking a moving light)

  Weakness because due to the artificial nature of the task and the setting, it may not reflect how memory works in everyday life
• Reductionist


  Gives a limited understanding of memory
• Criticisms of the working memory model

  • Incomplete - little evidence for how the central executive works
  • Does not explain sensory or long-term memory
  • The original 1974 model also did not explain how the working memory communicated with long-term memory-the episodic buffer was added in 2000 to explain this
• All of this means the validity of the original model may be reduced.
• Working memory model


  • Suggests strategies to improve memory, such as not attempting to do two tasks that use the same slave system simultaneously
• There are practical applications for the working memory model.
• Procedure

  1. Testing STM

  2. There were 15 participants in condition A, 20 in condition B, 16 in condition C and 21 in condition D

  3. For each condition, the 10 words were presented to participants on a projector for 3 seconds each (with a 2 second side changeover time between)

  4. Then there was a task involving STM for six sequences of eight digits (six tasks)

  5. They were then allowed 1 minute to write out the 10-word list in order - this was the test of memory

  6. After doing the above three bullet points four times, participants completed a task involving 15 minutes of copying eight-digit sequences at their own pace - this was an interference task put between the encoding and retrieval of the words

  7. Testing LTM - Then they attempted to recall the word list in order, which was a surprise retest
• Word lists

  • A) acoustically similar words - man, cab, can, cod, cap, mad, max, mat, cat, map
  • B) acoustically dissimilar words - pit, few, cow, pen, sup, bar, day, hot, rig, bun
  • C) semantically similar words - great, large, big, huge, broad, long, tall, fat, wide, high
  • D) semantically dissimilar words - good, huge, hot, safe, thin, deep, strong, foul, old, late
• In all groups, what was learned was retained for at least 15 minutes
• The results suggest that LTM may be based on either the meanings of the words (semantic) in the message or else on the sound of the words (acoustic)
• STM has an influence on the acoustic encoding which was shown by the difficulty of learning the list of acoustically similar words
• Whereas STM relies very largely on acoustic encoding and is relatively unaffected by the semantic content of the message, LTM uses semantic coding extensively, only being vulnerable to the effects of acoustic similarity in the learning stage where STM is involved, not with forgetting
• Baddeley's study

  • Lab experiment - very well controlled, could control extraneous variables and isolate the variable he wanted to measure
  • Standardised procedures - same word lists, equipment, timings for each participant in each condition
  • Overall, the experiment is very high in scientific credibility
• Baddeley said that although the study shows that in STM acoustic cues are important whereas in LTM semantic cues may be used instead, this difference between the two stores needs further research
• Cause and effect link between the IV of type of word list (acoustically similar/dissimilar or semantically similar/dissimilar) and the DV of correct sequential order of the word lists

  Increases the internal validity of the experiment
• Standardised procedures

  Increases reliability, meaning that the procedure can be replicated and produce consistent results