Monday, 6 February 2017

UNI ESSAYS Explain how psychological research has contributed to the idea that humans have both short and long term memory.

Memory is the capacity to encode, retain, store and retrieve information. We have 3 memory systems; Sensory memory, short-term memory and long-term memory. Short term memory is a process which preserves recent information over brief intervals. It is of limited capacity and duration and information is stored for a short amount of time without rehearsal. Miller (1956) summarized evidence that people can hold approximately 7 chunks of information in their short term memory give or take 2 chunks. Long term memory retains and preserves information for later retrieval over long periods. There is no known limit to long term memory. As the names suggest, Short Term Memory is short, lasting only for seconds and long term memory is long, lasting perhaps a lifetime. short term memory uses phonological encoding and long term memory uses semantic encoding.

Atkinson & Shiffrin (1986) developed a model of short term memory and long term memory. In the modal model of memory, short term memory and long term memory are presented as connected memory stores. The model illustrates how control processes such as rehearsal can transfer information into the long term memory. There were several issues with the modal modal. A patient known as KF had normal long term memory but a severely impaired short term memory (Shallice & Warrington (1970)). KF was still able to acquire and retain new information in long term memory. This proves that long term memories are not processed through the short term memory by way of rehearsal therefore the two memory stores must work individually.

The distinction between long term memory and short term memory was first made by William James (1890) who argued that primary memory (short term memory) holds whatever is in our consciousness, whilst secondary memory (long term memory) contains the sum of our past experiences.

Tulving (1985) theorised that there are 3 different types of long term memory; episodic (relating to people, places, events, actions), semantic (relating to knowledge i.e. knowing that if you touch something hot it burns you) and procedural (relating to know how. i.e knowing how to tie your shoes). Knowledge is organised into concepts and categories. Collins & Quillian (1969) devised the Semantic Network Theory whereby concepts are nodes and hierarchical in nature. There are links between concepts as they go up the hierarchy but there are no horizontal links between nodes. Using semantic networks it was found that it took longer to verify statements as they moved up the hierarchy. (i.e. it is easier to identify that a canary is a bird than it is to identify that a canary is an animal.

Atkinson, R. C., & Shiffrin, R. M., (1968) Human memory: A proposed system and its control processes The psychology of Learning and Motivation: Advances in research theory, 2, New York: Academic Press

Collins, A. M., & Quillian, M. R., (1969) Retrieval time from semantic memory Journal of verbal learning and verbal behaviour 8 (2) 240-247

Miller, G. A., (1956) The magic number seven, plus or minus 2: Some limits on our capacity for processing information. Psychological review 63 81-97

James, W., (1890) Principles of Psychology, Vol 1, New York: Holt, Rienhart & Winston

Shallice, T., & Warrington, K. E., (1970) Independent functioning of verbal memory stores: A neuropsychological study, The Quarterly Journal of Experimental Psychology 22 261-273

Tulving, E., (1985) How many memory systems are there? American Psychologist 40 385-398

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