Types of long-term memory

• Tulving proposed that there are in fact three LTM stores, containing different types of information (episodic memory, semantic memory and procedural memory).
• Episodic memory = our ability to recall personal events.
• Episodic memories are 'time-stamped'- you remember when they happened. Episodic memories include several elements and all of them are interwoven to produce a single memory.
• You have to make a conscious effort to recall episodic memories.
• Semantic memory = contains our knowledge of the world
• Semantic memories are not 'time-stamped', they are less personal and more about facts we all share.
• Procedural memory = store for our knowledge of how to do things
• Procedural memories are recalled without conscious awareness or a great deal of effort.
• Another strength is being able to identify different aspects of LTM allows psychologists to target certain kinds of memory in order to better people's lives. Belleville et al. demonstrated that episodic memories could be improved in older people. The trained participants performed better on a test of episodic memory after training than a control group. This shows that distinguishing between types of LTM enables specific treatments to be developed.
• A strength is evidence from the famous case studies of HM and Clive Wearing. Episodic memories in both men was severely impaired due to brain damage but their semantic memories were relatively unaffected. They still understood the meaning of words. Their procedural memories were also intact. They both still knew how to walk and speak. This supports Tulving’s view that there are different memory stores in LTM- one store can be damaged but the others are unaffected.
• Studying people with brain injuries can help researchers to understand how memory is supposed to work normally. But clinical studies are not perfect. They lack control of variables. The brain injuries experienced by participants were usually unexpected. The researchers had no way of what happened to the participant before or during the injury. The researcher has no knowledge of the individuals memory before the damage. Without this, it is difficult to judge exactly how much worse it is afterwards. This limits what clinical studies can tell us about different types of LTM.
• There is conflicting evidence linking types of LTM to areas of the brain. Buckner and Petersen concluded that semantic memory is located in the left side of the prefrontal cortex and episodic memory on the right. However, other research links the left prefrontal cortex with episodic memories and the right with semantic memories. This challenges any neurophysiological evidence as there is poor agreement on where each type might be located.