Evidence in support of the model includes work by Mudock’s serial position curve which showed a primary and recency effect. The primary and recency effect found by Glanzer and Cunitz suggests the existence of 2 separate stores. The first few words on the list go into the LTM store because they are sufficiently rehearsed, the last few words are held in the STM store from where they are last recalled. Acoustic rehersal is sometimes the best way of putting information into LTM for more permanent retention.
The brain damaged patients also supported the importance of verbal rehearsal, it indicates the existence of separate STM and LTM stores. KF, a motorbike victim, suffered damage to the STM but not his LTM. His STM capacity was only about 2 digits normally it is 7 plus or minus 2 digits. His LTM recall of events after the accident was normal. This suggests information can get into LTM even if the STM is damaged.
Brain damaged patients also provide evidence against the model which claims that memory is divided into single stores, several ways. KF’s STM was clearly more complex than a single store because his visual memory was better than his auditory memory. Research has shown that LTM is also not a single store, as both declarative and procedural knowledge have been identified. This means the MSM is over simplistic. The case of HM also showed that rehearsal may be an oversimplification as he was able to put memories in the short term store and hold it there by rehearsal but was not able to transfer it to the LTM. This suggests the transfer to LTM is more complex than simply rehearsal. The creation of flashbulb memories shows that rehearsal is not so important. Flashbulb memory creation suggests that rehearsal is not necessary for information in STM to pass to LTM.
The levels processing model also contradicts the MSM suggesting it is the depth or kind of processing, not the amount as in the MSM, which creates memories. The MSM portrays the STM as a passive store but later evidence suggested that it is an active and more complicated comprising 3 components however it does support the STM and LTM distinction identified by the MSM.
Another criticism is that the transfer of information is presented as a one-way process whereas the interference explanation of forgetting shows that information flow is two-way.
From looking at the MSM in detail, there is a lot more weaknesses than strengths, but the MSM was responsible for inspiring further research that improved and expanded on its original ideas. One strength is that it distinguishes between short-term and long-term stores in terms of capacity, duration and encoding. Another strength is that further evidence for the existence of separate stores comes from the laboratory experiments that have investigated primacy and recency effects.
Even though the MSM has stimulated considerate research, it is too simplistic and inflexible to explain the entire memory system, it fails to take account of factors such as the strategies people employ to remember things. Another weakness is that the MSM is criticized for focusing on the structure of the memory system at the expense of adequately explaining the processes involved. The other suggestion that has been criticized is that rehearsal is the only means of transfer from STM into LTM, rehearsal may be important for storing some information in LTM but people acquire new knowledge continually without using conscious rehearsal.