STRUCTURE OF WORKING MEMORY

STRUCTURE OF WORKING MEMORY

1. Multicomponent model.

   • Baddeley & Hitch 1974 assumed one component of WM is a limited capacity speEch based store capable of storing two to three items
     • This subsystem was described as an ARTICULATORY REHEARSAL LOOP
       • This can roughly be equated to the earlier concept of STM
         • Can be used to store small memory loads during cognitive tasks, and is responsible for the effect of phonemic similarity on performance.
           • Small irrelevant memory load can be stored in ARL (AL) without taxing the CENTRAL EXECUTIVE
   • Second component: described as CENTRAL EXECUTIVE,
     • Responsible for control & coordination of mental operations in a range of activities including but extending beyond reasoning, comprehension, learning and memory.
     • Seen as a limited capacity workspace that can be flexibly allocated to control processes or temporary info storage.
       • A larger memory load would take up extra memory resources in the CE.
         • Due to limit on capacity of workspace, this theoretical account maintains that there will be a trade off such that fewer resources are available to support processing operations when temporary storage demands increase.
   • Third Component: VISUO-SPATIAL SCRATCHPAD
     • Info from DUAL TASK studies (Baddeley & Hitch) suggests there are seperate resources for dealing with either verbal (ARL) or visuo-spatial info.
       • V-SS analogous to ARL
   • THIS TRIPARTITE MODEL WAS DEVELOPED FURTHER BY BADDELEY (1983, 1986). iLLUSTRATED ON PG 161 MAIN TEXT BOOK.
     • An interesting observation about thois model though is that neurological patients can show selective impairments in visuo-spatial STM and imagery tasks, suggestive of a separate brain location for V-S function. (pg161 MTB)
       • Using dual task methodology Badelley & Lieberman (1980) made observation that use of a visual imagery mnemonic was disrupted by a spatial task but not by a visual task.
         • This pattern not observed when the mnemonic strategy was rote rehearsal rather than imagery, indicating it wasn't a function of the relative difficulty of the spatial and visual interfering tasks.
           • B & L (1980) interpreted this as evidence that mental imagery is spatial rather than visual.
             • Hitch (1995) did some interesting research illuminating the idea that this counterintuitive conclusion did not generalise to all forms of imagery. MTB pg162 paragraph 1.
               • In review of visuo-spatial WM Logie (1995) suggested there were separate visual and spatial systems such that a spatial movement system can be used to rehearse the contents of a visual store.This corresponds to a visuo-spatial analogue of the articulatory loop.
                 • PHONOLOGICAL WORKING MEMORY: New Mind Map attached.
                   • PHONOLOGICAL WORKING MEMORY