MEMORY MODELS

MEMORY MODELS

1. Working Memory Model (WMM)

   • Originally designed by Baddeley and Hitch (1974), the Working Memory Model (WMM) is an alternative to the multi-store model of memory (MSM), which they saw as underestimating the complexities of the STM
   • How short-term memory works:It consists of several different components Each component has a particular function – includes not only storage but manipulation and analysis of information It is an active system which allows us to work things through. Two tasks can be carried out simultaneously in STM if they are being dealt with by different parts of the memory system
   • Central executive: Key component Supervises and coordinates information to and from the slave systems Very limited capacity It decides what needs to be done and when.
   • Phonological loop
     • Articulatory loop Active rehearsal system where words are maintained by subvocal repetition. Repeats info from phonological store Inner voice.
     • Phonological store Passive storage system Holds spoken information Inner ear.
   • Visuo- spatial sketchpad
     • Inner scribe Active rehearsal system Processes spatial and movement information.
     • Visual cache Passive visual store Stores info about visual form and colour.
   • Episodic buffer: Added in 2000 as the model needed a more general store. Slave systems deal with specific types of information. Central executive has no storage capacity Episodic Buffer is extra storage system but with limited capacity. it records events that happen, and sends information to the LTM.
   • Evaluation: evidence from brain damaged patients: Key evidence for the WMM comes from case studies of individuals who have suffered from serious brain damage. The process of brain injury is traumatic, which may change the behaviour of a person making them perform worse on certain tasks. these individuals have difficulty paying attention and therefore underperform in some tasks.
   • Evaluation: evidence from brain damaged patients: studies on a man called KF whose short term forgetting of auditory information was much greater than that of visual stimuli. In addition his auditory problems were limited to verbal material such as letters and digits but not meaningful sounds e.g. a phone ringing. his brain damage seemed to be restricted to his phonological loop.

2. Multi Store Memory (MSM) Atkinson and Shiffrin

   • Coding (Encoding): The way that info is changed so that it can be stored in a memory store. Environmental stimuli enters the brain and then is stored in various forms.
   • 3 unitary stores: sensory memory, short term memory (STM) and long term memory (LTM)
     • Sensory Memory: First is the SM its constantly receiving information, either visually, auditorily or haptically. But most of this information actually receives no attention and stays in the sensory memory until it decays (taking a matter of milliseconds). If a person is focusing on a piece of information, then instead of decaying it will be directly transferred to the STM.
     • Short Term Memory: When in the STM, information is very 'fragile' and likely to be displaced if its not rehearsed. The average duration for a piece of information in the STM is around 20 seconds and the amount of information that can be held is 7+/-2 items. If the information is rehearsed and payed attention too, then the information will be transferred to the LTM.
     • Long term memory: has a potentially unlimited capacity and the duration of which a piece of information can be held in the LTM is unlimited also.
   • Capacity: A measure of how much information can be stored in the memory.
   • Duration: How long a piece of information can stay in your memory before it is no longer available
   • Haptically: By touch. - Acoustically: By sound. - Semantically: By meaning. - Visually: By sight.
   • Attention: Information is transferred from one store to another. You pay attention to pass information from the sensory store to the STM
   • Forgetting: Memory traces in STM are fragile and can be lost within 30 seconds, through displacement or decay, unless they are repeated (rehearsed). Memory in the LTM is lost through decay, retrieval failure or interference.
   • Retrieval: The process of getting info from the LTM involves the information passing it back through the STM so its available for use.
   • Maintenance rehearsal: Repetition keeps info in the STM but eventually will create a LTM. Atkinson and Sheffrin proposed a direct link between rehearsal in STM and the strength of the LTM.
   • Evaluation: pts were given a list of 50 words that they needed to memorize in a given amount of time. This experiment found that there was a 'recency effect' where the pts remembered the most recent words that they had read because they had not yet been displaced from their STM, they also found that there was a 'primary effect' where the pts remembered the first words on the list because they had been rehearsed more and thus transferred into their LTM. These findings support the MSM because it shows that there are differences between the STM and the LTM and that they are 2 separate, unitary memory stores.
   • Evaluation: The MSM oversimplifies the memory structures and processes. The MSM suggests that the STM and the LTM are 2 different unitary stores which operate in a single, uniform fashion. But research opposes this. Someone known as 'KF' suffered from brain damage which resulted in them having difficulty processing verbal information in their STM. However, KF's ability to process visual information was completely normal. This suggests that the STM is a non-unitary store with different parts dedicated to processing different types of information (haptic, visual, auditory).
   • Evaluation: Lab studies on capacity, duration and coding support the existence of separate stores. Studies using brain scanning techniques have also demonstrated a difference between STM and LTM, The prefrontal cortex is active in STM tasks but not LTM ones and found the hippocampus is active in LTM tasks.

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