The multi-store model of memory suggested that there were three main stores: the sensory register, short term marmot and long-term memory. However, one criticism of this model is that long term memory is not as simple. In 1985 Endel Tulving suggested that the long-term moment was made up of three stores: episodic, semantic and procedural.
These memories are episodes in our life. They include the places, people, objects and behaviours involved etc… These memories are time stamped and they must consciously remembered.
This memory store is for our knowledge, the facts of the world. For example, words and concepts. Again, these must be recalled consciously
This memory store is about our skills, the knowledge on how to do things Examples could be walking, riding a bike and driving a car. We would often recall these memory without making a conscious effort.
We can use case studies to support the theory that long-term memory has multiple memory stores. Both Henry Molaison (HM) and Clive Wearing (CW) suffered from amnesia. Their episodic memories were heavily affected, and they struggled remembering past evens in their lives. But they both still knew the facts of the world, could speak etc… So, this indicates that their sematic memory was in place.
HM would be able to know that a dog had entered the room, what a dog was and so on but could not remember half an hour later that he had had that experience. He also would not be able to recall that growing up he had a pet dog. CW was a musician and although he could not remember passed events, he could still read music and play the piano showing his procedural memory was still in working order.
The advances in technology and brain scanning have also allowed us to show evidence that different areas of the brain are active during tasks designed for each memory store. Tulving et al. (1994) studied participants using a PET scan. They found that the left prefrontal cortex became active during the recall of semantic memories and the right prefrontal cortex for episodic.
Clinical evidence gives us real life accounts of patients with affected memories. Although there is a clear difference in the function of their long-term memory, we must consider that these stores are damaged. We must ask ourselves if we can generalise our results to the general population. We must also question the level of controls as this is very limited with significant variables that may affect their memory from their life experiences
Two or three types of Long-term memory
Tulving suggests that there are three types of long-term memory. However, Cohen and Squire (1980) suggest that there are simply two. These a decelerative and non-decelerative, weather the memory must be recalled consciously or not. Episodic and semantic would be declarative and procedural non-declarative.