Types of Long-term Memory Flashcards
Types of long-term memory (LTM)
Tulving (1985) was one of the first cognitive psychologists to realise that the multi-store model’s view of LTM was too simplistic and inflexible. Tulving proposed that there are in fact 3 LTM stores, containing quite different types of information. He called them episodic memory, semantic memory and procedural memory.
Episodic memory
Episodic memory = A LTM store for personal events. It includes memories of when events occurred and of the people, objects, places and behaviours involved. Memories from this store have to be retrieved consciously and with effort, and the memories are usually ‘time-stamped’.
Episodic memory refers to our ability to recall events (episodes) from our lives. This has been likened to a diary - a record of daily happenings. Some examples are: your most recent visit to the dentist, a gig you went to last week, the psychology class you had yesterday, the breakfast you ate this morning, and so on. These memories are much more complex than you might think. First of all, they are ‘time-stamped’ - in other words you remember when they happened. Secondly, your memory of a single episode will include several elements, such as people, places, objects, behaviours, and all of them are interwoven to produce a single memory. Thirdly, you have to make a conscious effort to recall episodic memories. You may be able to do so quickly, but you still aware that you are searching for your memory of what happened in that event.
Semantic memory
Semantic memory = A LTM store for our knowledge of the world. This includes facts and our knowledge of what words/concepts mean. These memories usually also need to be recalled deliberately but they are not usually ‘time-stamped’.
This store contains our knowledge of the world. This includes facts, but in the broadest possible sense. This type of memory has often been likened to a combination of an encyclopedia and a dictionary. So it would include knowledge of such things as applying to university, the taste of an orange and the meaning of words. This last one is important. Your semantic memory contains your knowledge of an impressive number of concepts such as ‘animals’, ‘Justin Bieber’ and ‘love’.
These memories are not ‘time-stamped’ - we don’t usually remember when we first learned about Justin Bieber, for example. Semantic knowledge is less personal and more about facts we all share. However, as the brief list about demonstrates, semantic memory is about much more than ‘facts’. It contains an immense collection of material which, given its nature, is constantly being added to.
Procedural memory
Procedural memory = A LTM store for our knowledge of how to do things. This includes our memories of learned skills. We usually recall these memories without making a conscious or deliberate effort.
This is our memory for actions, or skills, or basically how we do things. We can recall these memories without conscious awareness or a great deal of effort. A good example is driving a car. Our ability to do this (eventually) depends on procedural memory. We change gear without having to recall how. We indicate left/right at a junction without even realising we’ve done so.
These are the sorts of skills we might even find quite hard to explain to someone else. If you try to describe what you are doing as you drive the car, the task may well become more difficult.
Evaluation of the types of LTM
+ The famous case studies of HM and Clive Wearing are relevant here. Episodic memory in both men was severely impaired as a consequence of amnesia. They had great difficulty recalling events that have happened to them in their pasts. But their semantic memories were relatively unaffected. For example, they still understood the meanings of words. So HM would not be able to recall stroking a dog half an hour earlier and could not remember having owned a dog in the past, but he would not need to have the concept of ‘dog’ explain to him over and over again. Their procedural memories were also intact. They both knew how to tie their shoelaces, how to walk/speak, and in Clive Wearings’s case (he was a professional musician) how to read music, sing and play the piano.
This evidence supports Tulving’s view that there are different memory stores in LTM. One store can be damaged but others are unaffected. This is clear evidence that not only are these types of memory different, but they are stored in different parts of the brain.
+ There is also evidence from brain scans that different types of memory are stored in different parts of the brain. For example, Tulving et al. (1994) got their participants to perform various memory tasks while their brains were scanned using a PET scanner. They found that episodic and semantic memories were both recalled from an area of the brain known as the prefrontal cortex. This area is divided into 2, one on each side (or hemisphere) of the brain. The left prefrontal cortex was involved in recalling semantic memories. Episodic memories were recalled from the right prefrontal cortex. The strength of this finding is that it supports the view that there is a physical reality to the different types of LTM, within the brain. It has also been confirmed many times in later research studies, further support in the validity of this finding.
+ 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. (2006) demonstrated that episodic memories could be improved in older people who had a mild cognitive impairment. The trained participants performed better on a test of episodic memory after training than a control group. Episodic memory is the type of memory most often effect by mild cognitive impairment, which highlights the benefit of being able to distinguish between types of LTM – because it enables specific treatments to be developed.
