MODELS OF MEMORY: WM

MODELS OF MEMORY: WM

1. THE WORKING MEMORY MODEL: Developed by BADDELEY AND HITCH (1974). It is concerned ONLY WITH STM. It focuses on the systems by which information is processed, functions that it carries out and emphasising the idea of ACTIVE PROCESSING. Sees STM as FRACTIONATED. Explains why you can do two different tasks but not two similar tasks. Differs from MSM as MSM shows the stages are passive stores through which information flows.

2. EVIDENCE: Supported by the fact that there are different sub-systems in STM and visual processing must be included in any model of STM whereas emphasis on acoustic encoding in MSM. PET scan studies of brain activity (carried out by Wellcome Foundation). The 3D scan shows activity in the brain in different areas when different tasks are carried out.

   • APPLICATIONS: Can be used when children with normal intelligence are having difficulty in learning to read and recognising rhyme, it could mean there is a problem with the ARTICULATORY LOOP. Interventions focusing on the loop could support children.

3. CRITICISMS: Limited because it only focuses on STM. Also the model is still under development e.g. BADDELEY (1996) suggested that the central executive could be fractioned into four functions: ALLOCATING ATTENTION; SWITCHING RETRIEVAL STRATEGIES; COORDINATING PERFORMANCE; AND PROCESSING CAPACITY. BADDELEY (1996) supported this with research demonstrating that people with ALZHEIMER'S have difficulty carrying out two tasks simultaneously, while normal aging is associated with difficulty in focusing attention, two different aspects on the central executive.

4. STRUCTURE

   • CENTRAL EXECUTIVE controls the three slave systems so its the most important part of WM. Thought of as a limited-capacity workspace and used flexibly to control parts of the system. It is MODALITY-FREE (as it can process information from any senses). Used when carrying out difficult mental tasks, acts as an attention system and as a temporary storage of information while another task is being carried out.
     • VISUO-SPATIAL SCRATCHPAD: Referred to as the INNER EYE. Uses a VISUAL CODE and processes visual and spatial information (like abstract patterns) which cannot be easily translated into acoustic code.
     • ARTICULATORY LOOP/ PHONOLOGICAL LOOP: Referred to as the INNER VOICE. Holds information in an AUDITORY code (like remembering a phone number long enough by 'hearing' what you heard in your head). The capacity is as much information as could be repeated in 2 seconds, this was established by BADDELEY ET AL (1975). The capacity is limited by time rather than number of items. The role has been demonstrated using CONCURRENT VERBALISATION (asked to repeat a phrase out loud while reading or learning a list of words, the second task is impaired). Repeating the phrase occupies the articulatory loop, making it unavailable for the other task. This is called ARTICULATORY SUPPRESSION. The distinction between the scratchpad and articulatory loop are demonstrated by DEN HEYER AND BARRETT (1971).
       • DEN HEYER AND BARRETT (1971): The aim was to investigate the coding of material in STM using MODALITY SPECIFIC INTERFERENCE. Participants were shown a gird and asked to remember both the letter and position on the grid. They were given a VERBAL or VISUAL interference task. Then they had to complete the grid they had seen. The results were scored on the number of letters correctly remembered and the number of correct positions. The results showed that recall of the letters were disrupted by the verbal task and position recall was disrupted by the visual task. To conclude, the letters were encoded acoustically and the positions were encoded visually. This supports the idea of separate systems in STM.
     • PRIMARY ACOUSTIC STORE: Referred to as the INNER EAR. This was a later addition to the model. It receives information from the ears or the articulatory loop and is encoded ACOUSTICALLY. The concept was added when information presented acoustically was not affected by articulatory suppression.