PassingPsych

Memory is the process of encoding, storing and retrieving information. The Working Memory Model (WMM) by Baddeley and Hitch argues that the concept of short-term memory should be replaced with something more detailed, working memory. It challenged one of the main limitations of the MSM ( Multi-store memory model), in that the STM (Short-term Memory) must have more than one unitary store. They proposed that the STM consists of several components:  the Central Executive system( which drives the whole system and processes any type of sensory information), the Phonological loop (Deals with spoken and written material, and consists of the Phonological store and Articulatory control process), Visuospatial Sketchpad(responsible for processing and storing visual and spatial information), and Episodic Buffer (acts as a backup store, which communicates with both Long term memory store and components of WMM). In this essay, I will give a brief account of the WMM and the supporting study of Salmon et al.

Salmon et al aimed to replicate previous findings concerning the brain areas activated by a verbal working memory task, to investigate a lab experiment. The experiment consisted of 10 right-handed European men, who gave written informed consent to take part in the study. Pet scans of regional cerebral blood flow were obtained for each participant. In The visual short-term memory task, six Korean letters (which could not be transcoded into phonological code) were randomly presented on a computer screen at a rate of one per second. Subjects were asked to remember the stimuli using a visual code and to judge if a probe Korean letter displayed 2 seconds after each sequence was present in this particular sequence, they pressed yes/no on a control pad if they recognised a letter/shape. In the phonological STM task, randomised sequences of six phonologically dissimilar consonants were displayed on the monitor. Subjects were instructed to rehearse the stimuli silently and to remember them serially to detect whether a target consonant presented 2 seconds after this string was present in the list. Results showed that for the phonological loop, the lower left supramarginal gyrus and premotor area are key regions associated with short-term verbal memory processes. For the Visuo spatial sketchpad, the superior gyrus was associated with visual short-term memory.  

Salmon demonstrates the existence of the visuospatial sketchpad and the phonological loop, different components of the STM. This can be seen in different areas of the brain being activated during the visual task and phonological task. This is important as it shows the STM is not a unitary store and there must be multiple STM components. Therefore this study supports the assumption that the WMM and that the STM is composed of the visuo-sketchpad and phonological loops.