Memory

• Memory systems

  A cognitive approach to explaining how our memory works
• STM and LTM

  • Differ in function, capacity, duration, encoding, and forgetting
• LTM capacity


  Potentially unlimited
• STM duration


  Roughly 30 seconds
• LTM duration


  Potentially unlimited
• Retention interval

  The time between which you learn information and have to then recall it
• Encoding

  The form in which information is stored and transmitted
• Jacobs' study into capacity of STM


  1. Presented participants with a string of letters or numbers

  2. Had them repeat them back in the same order

  3. Increased the number of letters or numbers until the participant failed

  4. Average is 7+/- 2, slightly more for numbers than letters
• Peterson and Peterson's study into duration of STM


  1. Took 24 undergrad students

  2. Gave them a nonsense trigram to remember

  3. Told them to count backwards for 3, 6, 9, 12, 15, or 18 seconds to prevent rehearsal

  4. Found 80% accuracy at 3 seconds, 5% at 18 seconds
• Peterson and Peterson's study lacked realism as nonsense trigrams are unlike info we typically deal with
• The use of interference tasks in Peterson and Peterson's study proves to be an issue as we cannot be sure if information has decayed or just been displaced
• Baddeley's study into coding in STM and LTM


  1. Gave different lists of 4 words for participants to remember

  2. Lists were either acoustically similar, acoustically dissimilar, semantically similar, or semantically dissimilar

  3. Participants did worse on acoustically similar words when recalled immediately, but worse on semantically similar words after 20 minutes
• Baddeley's study into coding lacked ecological validity due to the artificial nature, so it may not be generalisable to all types of memory tasks
• Baddeley's study into coding has limited application
• Bahrick et al's study into duration of LTM


  1. Tested 392 US participants who had left high school 1-48 years prior

  2. Had to recall as many classmates as possible using free recall, recognition of photos, or name recognition and photo matching

  3. Recall was very high with 80% accuracy for name recognition at 48 years and 30% accuracy for free recall at 30 years
• Classmates in Bahrick et al's study have high emotional significance, so there is no control over rehearsal
• Conclusion from Bahrick et al's study into duration of LTM may not be generalisable into other types of information
• MSM of Memory


  Developed by Atkinson and Shiffrin, saw memory as a flow of information through an information processing system divided into 3 stages: sensory registers, STM, and LTM
• Sensory registers


  • Take in information from all senses, mainly echoic and iconic
  • Have very high capacity but very short duration
  • Attention is used to choose important information
• Rehearsal


  • Maintenance rehearsal in STM keeps info fresh by repeating it
  • Elaborative rehearsal moves info into LTM
• Recall

  Memories have to be moved from LTM into STM, none can come directly from LTM
• Positives of the MSM


  • Makes good intuitive sense and gave a good "starting point" for research
  • Plenty of research shows STM and LTM are qualitatively different
• Negatives of the MSM


  • Oversimplifies as there is more than one type of STM and LTM
  • STM is not a unitary store as patients with amnesia have poor STM for read aloud info but better for seen info
  • Suggests memory happens through rehearsal but further research shows type of rehearsal is more important
• Positives of Tulving's theory of 3 types of LTM


  • Clive Wearing's case shows how episodic memory can be severely impaired without the other two types being affected
  • Tulving got participants to perform memory tasks during a pet scan and while episodic and semantic memory were both recalled from the prefrontal cortex, opposite sides were used for either type
  • His research has led to developments in treatments - episodic memories can be improved in patients with mild cognitive impairments
• WMM


  An active system concerned with STM, or the part of the mind that is being used while temporarily storing information. It was developed by Baddeley and Hitch in 1974.
• WMM


  • It is a complex yet flexible system that accesses info from the LTM
  • It is limited and can only cope with a small amount of information at once - it is also easily interrupted
• Central Executive

  The master system and acts like attention - it has overall control. It has limited capacity but can process from any sense. It will direct the most important information and is responsible for controlling the other two slave systems. It is the most flexible component in the WMM, but its complexity makes it difficult to research.
• Phonological Loop

  The first slave system and it deals with auditory information. It is split into the Phonological Store (the inner ear) which stores words as they are heard and the Articulatory Process (the inner voice) which allows maintenance rehearsal. The Phonological Loop lasts about 2 seconds.
• Visuo-Spatial Sketchpad

  Another slave system and it deals with visual and spatial information. It is a temporary store for what items are and where they are located. It has a limited capacity of about 3 or 4 items and helps us navigate the world around us with a "mental picture"
• Episodic Buffer

  The third slave system and was added to the WMM in 2000. It is a temporary general store, combining information from the Phonological Loop, Visuo-Spatial Sketchpad and the LTM. It helps create an "episode" in our life and was added to explain certain aspects of memory like the difference in ease of recalling 100 words in continuous prose compared to recalling 100 unrelated words.
• Positives of the WMM


  • Offers an explanation of why we can do different tasks at once but not two of the same vain
  • PET scans indicate different brain areas activated during visual and verbal tasks
  • It is supported by research such as the "Word length effect" research by Baddeley - the idea we can recall more short words than long ones as more can fit into our Phonological Loop
  • It is a more plausible model than the MSM as it explain memory as an active process rather than just passive storage
• Negatives of the WMM


  • The Central Executive is never clearly defined and it's never really clear what it does - it is essentially the same as attention. It cannot be a single component as it is so complex
  • Baddeley suggests that due to the complexity of the model it is "significantly harder to research" and therefore there is less research evidence to support its existence
  • The WMM has also been criticised for failing to consider how it works with LTM and not being a comprehensive enough model
• Interference


  At least some forgetting takes place because of interference. It occurs when two or more pieces of information conflict and compete with each other which results in forgetting or having some distortion in the memory.
• Proactive Interference


  When an older memory interferes with a newer one
• Retroactive Interference


  When a newer memory interferes with an older one
• McGeoch and McDonald's study into interference


  • They gave Participants lists of words to learn to 100% accuracy. They then learned a new list that consisted of either: synonyms, antonyms, unrelated words, nonsense syllables, 3 digit numbers, or no new list. They found that recall was worst with the most similar material - interference is therefore strongest with similar memories
• Positives of interference as an explanation of forgetting


  • Very consistent in terms of findings - 1000s of lab studies with the same results
  • Lab experiments are typically used and are highly controlled so a good sense of cause and effect
• Negatives of interference as an explanation of forgetting


  • There is an element of artificiality into studies of interference
• Baddeley and Hitch's study into interference


  • They asked rugby players to recall the matches they had played that season week by week, in order. Those who had missed matches due to injury could recall far more accurately no matter the time since they last played. This showed that memory was affected not by time but by the amount of similar information stored in between.
• Retrieval Failure


  People forget information because of a lack of sufficient cues. When information is initially placed into memory, associated cues are stored at the same time - if these cues are not available at the time of recall, it may seem like you've forgotten the information but you are actually just suffering from retrieval failure.