Memory models in general:

• The complex processes in how memory is structured and how it functions
• The effectiveness of each model can be determined by validity, reliability, and empirical evidence.

Multi-store model:

• Atkinson & Shiffirin
•  They proposed that memory consisted of three stores: a sensory register, short-term memory (STM) and long-term memory (LTM).
• Processes: Information is detected by the sense organs and enters the sensory memory. If attended to this information enters the short term memory. Information from the short-term memory is transferred to the long-term memory only if that information is rehearsed (i.e. repeated). If maintenance rehearsal (repetition) does not occur, then information is forgotten, and lost from short term memory through the processes of displacement or decay.

Three characteristics:

• Encoding is the way information is changed so that it can be stored in the memory. There are three main ways in which information can be encoded (changed): 1. visual (picture), 2. acoustic (sound), 3. semantic (meaning).
• Capacity concerns how much information can be stored.
• Duration refers to the period of time information can last in the memory stores.

Sensory memory:

• This is a temporary store holding information from the environment very briefly in the form in which it is received – that is, visual, auditory, tactile or olfactory. Information needs to receive attention if it is going to begin the process of being transferred to long term memory.
• Encoding: sense specific(e.g. different stores for each sense)
• Capacity: all sensory experience (v. larger capacity)
• Duration: ¼ to ½ second

Short-term memory: 

• This is a store with limited capacity and duration. If new information enters the STM then the information in the store may be displaced and lost. Information enters STM from the sensory store if attention is paid to the stimuli. In addition, when we recall something it is taken out of long-term memory and enters our STM so that decisions can be made and problems can be solved.
• Encoding: mainly auditory
• Capacity: 7 +/- 2 items
• Duration: 0-18 seconds

Long-term memory:

• This is where memory is stored after it has been rehearsed while in STM. LTM is of unlimited capacity and duration.
• Encoding: Mainly Semantic (but can be visual and auditory)
• Capacity: Unlimited
• Duration: Unlimited

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Key study 1:

• Glanzer & Cunitz

A – To investigate the words remembered from a list of 20 items

M – list of 20 words, 0 second delay, 10 second delay, 30 second delay

R –  0 = first 5 and last three words, 10/30 = poor recall of later items

C – Later words (recency effect) were held in short-term storage and lost due to interference whereas earlier words (primacy effect) had been passed to long-term storage

• Glanzer and Cunitz showed that when participants are presented with a list of words, they tend to remember the first few and last few words and are more likely to forget those in the middle of the list, i.e. the serial position effect.
• This supports the existence of separate LTM and STM stores because they observed a primacy and recency effect. Words early on in the list were put into long term memory (primacy effect) because the person has time to rehearse the word, and words from the end went into short term memory (recency effect).

Key study 2:

• Brenda Milner and H.M

① STM and LTM are separate stores – he still had LTM working from before his brain damage, but he could not form new     LTMs

• HM, when asked to recall the stimulus script after 1 hour, couldn’t remember what the story is.
• Knows public figure and rock music.

② The hippocampus (a biological part of the brain) is necessary for transferring STM to LTM

• Central portions of his brain were sucked out with a silver straw, and he failed to form any new LTMs

③ Memory is more complex than originally thought by MSM e.g. we have procedural and episodic memories in LTM. H.M   got better at procedural memories

• H.M had a normal learning curve for the star drawing task, just like everyone else
• shows different between declarative learning and non-declarative learning

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Critical analysis:

Strengths:

• it is gives us a good understanding of the structure and process of the STM
• allows researcher to expand on this model
• influential as it has generated a lot of research into memory
• Many memory studies provide evidence to support the distinction between STM and LTM in terms of the three characteristics

Weaknesses:

• The model is oversimplified: in particular when it suggests that both short-term and long-term memory each operate in a single, uniform fashion.
• Rehearsal is considered a too simple explanation to account for the transfer of information from STM to LTM – ignored motivation, effect and strategy
• rehearsal is not essential to transfer information into LTM – we never rehearsed how to swim
• The models main emphasis was on structure and tends to neglect the process
• criticised for being a passive/one way/linear model.

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Potential SAQs:

1. Describe one memory model, using one example of relevant research to support your answer.
2. Outline the multi-store model of memory.
3. Explain how biological factors may affect one cognitive process (for example, Alzheimer’s disease, brain damage, sleep deprivation).

Potential ERQs:

1. Contrast two models of memory.
2. Evaluate one model of memory.
3. Evaluate one study related to one model of memory.
4. Discuss models of memory.