Discuss Explanations of Forgetting

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We forget things for two reasons, firstly the memory has disappeared- it is no longer available or secondly the memory is stored in the memory system but cannot be retrieved. The first theory is more likely to be applicable to forgetting in the short term memory and the second in the long term memory. You can differentiate between availability and accessibility. Availability is whether the information has been stored in the memory or not and accessibility is the ability or inability to retrieve information if it has been stored. Forgetting information from the short term memory can be explained using the theories of trace decay and displacement. In reference to the multi store model of memory the theory states that in the STM both capacity and duration are limited. The capacity of STM is about 5-9 units of information and the duration of STM is given at only a few seconds, to a maximum of a minute or so. As information cannot stay indefinitely In STM, if it is not transferred into LTM it will be forgotten. Therefore theories of forgetting in STM are based on availability. There are two main theories about how information is lost from the STM, trace decay and displacement theories. Trace decay theory of forgetting (STM) relates to both long term and short term memory and also relates to lack of availability. The theory suggests that the STM can only hold information for between 15 and 30 seconds unless it is rehearsed. After this time the information decays (fades away). This explanation of forgetting in short term memory assumes that memories leave a trace in the brain. A trace is some sort of physical/chemical change in the nervous system. Trace decay theory states that forgetting occurs as a result of the automatic decay or fading of the memory trace. Trace decay theory focuses on time and the limited duration of short-term memory. Decay theory assumes that memories have a physical or biological basis in the brain, and that the encoding of memories involves a structural change in the brain. The physical representation of a memory is called a memory trace or an engram. This theory sees forgetting as the physical breakdown or decay of the memory trace. Assuming that rehearsal does not take place, the mere passage of time will cause the memory trace to break down. This explains why forgetfulness increases with time. According to the theory, metabolic processes happen over time which causes the structural change to break down if it is not maintained through repetition. Strengths of the decay theory are that it appeals to common sense that if we don’t use/activate the memory we will lose it. However the theory also has weaknesses and it does not explain why some older memories (especially in those who have Alzheimer’s) are not lost and can still be remembered whereas newer memories seem to decay more easily/quicker. A theory that supports decay theory is Peterson and Peterson (1959). They provide evidence for this theory. They conducted a study where they asked participants to recall a string of consonants selected so as to be difficult to pronounce. Recall delay was set to 3, 6, 9, 12, 15 and 18 during which rehearsal was prevented by participants counting backwards in threes from a target number (e.g. 397). Each subject was tested a total of 8 times at each of the 6 delay intervals. The findings of the study showed that while after a 3 second retention interval trigrams about 90% of trigrams were recalled, after 18 seconds only 10% were. The duration of STM without retention is very short. In terms of decay theory, the engram could not grow stronger and so broke down. Another theory of forgetting in the short term memory is the displacement theory. This theory suggests that new information received by the STM overwrites or displaces previous information. In a system of limited capacity, forgetting would take place through displacement in STM. According to this theory, when the system is full, the new information will...
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