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.