Saturday, August 24, 2013
Memory: Declarative and Non-Declarative
Declarative (also called explicit) memory records facts, such as names, places, and experiences. It is a type of long-term memory, and a conscious memory, in that the facts can be recalled at will by an individual (Breedlove, Watson, & Rosenzweig, 2010). This memory system relies on the faculties of the medial temporal areas of the brain, in particular, the hippocampus (Breedlove et al., 2010). Declarative memory has two subtypes; semantic and episodic memory. Episodic memory stores personal information and experiences, while semantic memory stores factual information.
For example, semantic memory stores factual information based on ideas and supports the conscious recollection of knowledge. Semantic memory allows people to create meaning because of past experience, in a way, building on previously learned information (Saumier & Chertkow, 2002; Squire & Zola, 1996). It includes generalized information such as remembering that a cat is an animal rather than a cooking utensil. Using the cat example, this type of memory allows individuals to know the information about the cat even though neither cats nor cooking utensils are present in the moment of the information retrieval (Tulving, 1993).
Episodic memory stores personalized experiences or autobiographical events, such as emotions associated with specific circumstances that can be articulated. This type of memory is exampled in a woman's ability to recall every detail of giving birth to her first child, or an old man recalling the details of attending his first baseball game at Fenway Park. Tulving (2001) referred to episodic memory as the ability of individuals to consciously travel back in time to revisit experiences ripe with feeling and personal emotion. In sum, semantic memory supports basic or generalized knowledge, whereas episodic memory supports the recollection of feelings of personal experience (Hassibis & Maguire, 2007). Tulving (2002) believed episodic memory was an exclusively human trait.
Non-declarative or Procedural Memory
Non-declarative or procedural memory is a long-term memory type as well, although this is an unconscious memory that accounts for remembering skills for extended periods, even when the task is not done on a regular basis. Common examples include remembering how to drive a car, although it has been five years since the task has been done, or remembering how to wind a music box, although one has not been touched in 20 years. Although tasks carried out with procedural memory may be easily accomplished, an individual may have difficulty describing just how the task is done. H.M., although unable to develop new declarative memories, was able to learn, albeit subconsciously, new tasks (Milner, 2010).
Priming, Skill Learning, Conditioning: The Acquisition of Procedural Memory
Procedural memory is acquired by several means. Priming, sometimes referred to as repetition priming, is the process of exposure to a stimulus that results in an individual responding to the same or similar stimulus at another time. According to Wagner and Koutstaal (2002), priming is concerned with exposure to a word or face (for example) which encourages a response to the same word or face at a later time. This process is said to increase the speed of response and accuracy of the response an biases the response that will be given subsequently (Wagner & Koutstaal, 2002). H.M. was subject to priming by being shown a list of words, although he did not remember being shown the list (Breedlove et al., 2010).
Priming is similar to conditioning, which is learning by associating two stimuli over time, or a stimulus and a response. The complexity of the skill associated with conditioning determines the brain area responsible for the conditioning (Breedlove et al., 2010). Skill learning is "learning to perform a task that requires motor coordination" (Breedlove, 2010, p. G-27). After learning this skill, it continues to be accomplished without conscious thought, such as when one ties her shoes or dries themselves after a shower. H.M.'s task of learning to read text in a mirror is another example of skill learning. After several tries, H.M. learned to read the reversed text even though he did not recall consciously, attempting the task previously (Breedlove et al., 2010).
Declarative and Non-declarative Memory Loss and a Personal Choice
A declarative memory loss would account for an individual not being able to do basic math, or remember the first time her child walked. This type of memory loss might occur because of damage to the hippocampus (Breedlove et al., 2010) and could result in an individual losing a significant amount of personal biographical information as well as generalized information, for example, not remembering for what a spoon is used. A loss of non-declarative memory would affect the individual's ability to care for themselves, for example, forgetting how to feed themselves, make a sandwich, or ride an escalator.
I would rather retain my declarative memory, if I had the choice. I could contend with forgetting how to tie my shoes or drive a car, but it would seem far more tragic to not have the ability to remember my family or the first time my children walked. Although I would certainly be someone's burden with a non-declarative memory loss, I would rather keep my semantic and episodic memories intact. I would not, however, understate the challenges of losing one's non-declarative memory. Not having the capacity to remember or re-learn basic tasks that I do without thinking would be a tremendous disability.
Breedlove, S. M., Watson, N. V., & Rosenzweig, M. R. (2010). Biological psychology: An introduction to behavioral, cognitive, and clinical neuroscience. (6th ed.) Sunderland, MA: Sinauer Associates, Inc. Publishers.
Graf, P. & Mandler, G. (1984). Activation makes words more accessible, but not necessarily more retrievable. Journal of Verbal Learning and Verbal Behavior, 23, 553-568.
Anosognosia Lack of insight to or awareness of the condition
Hassabis, D., & Maguire, E. (2007). Deconstructing episodic memory with construction. Trends in Cognitive Sciences, 11(7), 299-306. doi: 10.1016/j.tics.2007.05.001
Milner, B. (2010). Reflections on the field of brain and memory: A tribute to H.M. NARSAD Research Quarterly, 3(1), 24–25.
Retrieved from the Walden Library databases.
Saumier, D., & Chertkow, H. (2002). Semantic memory. Current Neurology and Neuroscience Reports, 2(6), 516-522. doi: 10.1007/s11910-002-0039-9
Squire, L. R., & Zola S. M. (1996). Structure and function of declarative and nondeclarative memory systems. Proceedings of the National Academy of Sciences of the USA, 93(24), 13515–13522. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/8942965
Tulving, E. (1993). What Is Episodic Memory?. Current Directions In Psychological Science, (3), 67. doi:10.2307/20182204
Tulving, E. (2002). Episodic memory: From mind to brain. Annual Review Of Psychology, 53(1), 1.
Wagner, A. D., & Koutstaal, W. (2001). Priming. In Encyclopedia of the human Brain (Vol. 4, pp. 27-46). Elsevier Science.