Cognitive Memory Models

Multi Store Model of Memory: Atkinson & Shiffrin (1968)

• The sensory register - The sensory register is a buffer for all information from the environment. Its capacity is 4 items (4 letters in an array) and a duration of half a second. Information is transferred into the short term memory if attention is paid to it and the sensory register encodes in all modalities.
• Short term memory - The duration of the STM is 15-30 seconds and then information decays/displaces unless it is transferred into the long term memory through rehearsal. The capacity of the STM is 7 +/- 2 items and it is suggested that grouping certains items together so that they seem logical in the brain are useful for memory. Encoding in the STM is mainly acoustic.
• Long term memory - The duration of the LTM is lifelong and its capacity is infinite. Encoding in the LTM is mainly semantic.
• To transfer information from the short term memory to the long term memory we must make sense of it and assign verbal labels. Transfer does require rehearsal and also cognitive effort.

The Working Memory Model: Baddeley and Hitch (1974)

• The model was proposed as an alternative to the MSM which they said was too simplistic in the emphasis on the role of rehearsal and challenging the idea that the STM is a single store. 
• We rely on working memory for many functions such as remembering telephone numbers and lists, comprehending sequences in the form of sentences, mental calculations and reasonings. It is fragile and vulnerable to distractions (such as someone talking when you're trying to remember a number).
• The central executive - Puts information from different…