Long Term Memory
Long Term Memory
Long Term Memory
Long-term memory is a complex system that was first recognized by Tulving in 1985 as having more than the single store proposed by Atkinson and Shiffrin in 1968. Tulving proposed that long-term memory consists of three distinct types: episodic, semantic, and procedural memories.
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Episodic Memory:
Episodic memories are the capacity to recall personal events from our lives. These memories are time-stamped events, akin to diary entries, and include details about where we were, what happened, and other associated specifics. For instance, recalling last year's birthday events or a concert attended during the summer are examples of episodic memories. They are multifaceted, encompassing details about people, places, and various aspects, and require conscious effort to recall.
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Semantic Memory:
Semantic memory pertains to our general world knowledge, such as our knowledge of psychology, remembering the latest song released by a favorite band, or recalling the score and goal scorer from a recent football match. This type of memory encompasses a broad range of knowledge, often tested in quiz shows, and like episodic memory, it involves conscious recollection and is personal to us.
Procedural Memory:
Procedural memories are our recollections of how to perform tasks and are often considered akin to muscle memory. They are challenging to articulate; for instance, explaining how to ride a bike or swim is tough without physically demonstrating the action. These memories typically don't require much conscious effort to recall; we seem to instinctively know how to execute them. Over time, procedural memories become automatic. Take driving as an example: initially, you might concentrate intently on the engine's sound and your hand on the gear shift, but eventually, it becomes automatic, and we perform actions without even realizing it.
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Evaluation:
1. ​One strength of Tulving's theory is the substantial evidence from case studies such as those of HM and Clive Wearing. In these cases, both men exhibited impaired episodic memories, while their semantic and procedural memories remained relatively intact. For instance, HM was able to learn new procedural memories despite having no recollection of performing the tasks. For example, in one study he was given a mirror drawing task over several days, and showed improvement on the task, without any conscious memory of it.
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2. Another strength of long-term memory research is its potential to aid individuals with memory impairments. As people age, they often face memory challenges, such as dementia. Much of the memory loss appears to be specific to certain types of memory, episodic memories. Belleville et al. in 2006, investigated this and developed interventions to enhance episodic memory in the elderly. Their findings indicated that, compared to a control group, those who received memory training performed better on tests of episodic memory.
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3. Tulving's 1994 brain scan research provided evidence that different types of long-term memory are located in distinct areas of the brain. During PET scans, subjects performed various tasks, revealing that episodic memories are associated with the right prefrontal cortex, while semantic memories are linked to the left prefrontal cortex. This evidence supports the theory that long-term memories are not only different in type but also in their brain locations, thereby bolstering the credibility of Tulving's theory.
4. A critique of Tulving's theory arises from Cowan and Squire's 1980 proposition that episodic and semantic memories are so intertwined—being consciously recalled and sometimes containing elements of each other—that they should be classified as declarative memories. This classification implies that such memories can be consciously retrieved. Conversely, they suggested that procedural memories be categorised as non-declarative, as they do not require conscious recall from memory.
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5. Another issue concerns the clinical evidence from cases like Clive Wearing and HM, where there has been a lack of control in the studies. This lack of control compromises the validity of the evidence supporting the existence of distinct types of long-term memory.