Discuss Explanations of Forgetting

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