AO1 - WMM
Baddeley and Hitch developed the WMM due to criticisms of the MSM, which showed the STM as a unitary store. They said that the STM consistsof three parts - the central executive (controls everything in STM, delegates to two slave systems - the visuo-spatial scratchpad and the phonological loop). The VS deals with all visual and spatial sensory memories, and the PL deals with auditory and verbal rehearsal.
AO2 - Support
KF - suffered severe brain damage, resulting in loss of his auditory memory (2 on digit span technique), whilst his visual and LTM remained intact. Applying the theory of the WMM, we can see that he only suffered the loss of his PL - this shows that memory is not unitary, as the WMM suggests.
AO2 - Criticisms
1. Shah and Miyake questioned the exact fole of the central executive, and whether it can be considered a single component. This brings the whole accuracy of the WMM into question.
2. Berz (1995) said that the WMM fails to account for musical memory - it can't explain why we can listen to music whilst completing other acoustic tasks. This suggests that the memory is more complex than the WMM suggests.