Working memory model evaluations

baddeley and hitch

Clinical evidence

One strength is support from Shallice and Warrington’s case study of KF.

After his brain injury, KF had poor STM ability for auditory information but could process visual information normally. Recall of letters and digits better when he read them then when they were read out to him. KF’s phonological loop was damaged but his visuo-spatial sketchpad was intact.

Findings support the existence of separate visual and acoustic memory stores.

Dual-task performance

Another strength is that studies of dual task performance support the separate existence of the visuo- spatial sketchpad.

When Baddeley et al’s participants carried out a visual and verbal task at the same time, their performance on each was similar to when they carried out the tasks separately. But, when both tasks were visual (or both were verbal), performance on both declined substantially. This is because both visual tasks compete for the same subsystem (the visual-spatial sketchpad), whereas there is no competition when performing a verbal and visual task together.

This shows there must be a separate subsystem that processes visual input (VSS) and one for verbal processing (PL).

nature of the central executive (limitation)

One limitation is the lack of clarity over the nature of the central executive.

Even Baddeley who founded the WMM says the central executive is the most important but least understood component of working memory. Some psychologists believe the CE may consist of separate subcomponents.

CE is an unsatisfactory component and thus challenges the integrity and use of the wmm.

unrepresentative tasks used in research

eg digit recall