Difference between Short-term Memory and Long-term Memory

The short-term memory differs from the long-term memory in the following ways:

1. Short-term memory is viewed as a rapidly decaying system. Most psychologists believe that short-term memory does not involve permanent changes in the brain. However, some temporary changes occur in this case. The physiological nature of the traces is such that they fade quickly. The long-term memory appears to be permanent. A permanent change occurs in our brain when we remember things for a longtime. Long-term memory has a more or less enduring impression on the brain. Because of the consolidation of traces, the traces are relatively permanent.

2. Short-term memory has limited storage capacity resistant to overcrowding in any form. It just cannot take any overload. On the other hand, long-term memory is limitless for all practical purposes. Any information transferred from short-term memory to long-term memory will have a place for permanent storage.

3. Short-term memory is an active system involving rehearsal. We need to keep the items actively in STM relearning them constantly. On the other hand, the long-term memory is rather passive in nature; it is not easily disturbed by interruption, unlike short-term memory.

4. Long-term memory differs from short-term memory in the kind of information that is most easily stored. Information is usually stored in short-term memory in terms of the physical qualities of the experience (what we see, do, taste, touch, hear etc.) with a special emphasis on acoustic (sense of hearing) codes. Although sensory memories can be stored in long-term memory, information is primarily stored in LTM in terms of its meaning or semantic codes.

5. There is a difference between long-term memory and short-term memory in the process of recall. When we are looking for a bit of information in STM we scan the entire contents of this store. But as the amount of information stored in long-term memory is lost, we cannot scan the entire contents of the LTM when we are looking for a bit of information. We use a cue relevant to the information we need and retrieve only that information instead of the entire contents of LTM.

6. Short-term memory also differs from long-term memory in the way forgetting occurs. Short-term memory is characterized by trace dependent forgetting. If information is not rehearsed or processed immediately, then the memory transformed by the information fades rapidly and the item is permanently lost or completely erased from the memory, in contrast, long-term memory is characterized by cue dependent forgetting. The information is permanently recorded in LTM but our ability to retrieve it depends upon having the appropriate cues

7. The different stages of memory are handled by different parts of the brain. Short-term memory is primarily a function of the frontal lobe of the cerebral context, while information that is stored in long-term memory. is first held in the hippocampus and then transferred to the areas of the cerebral cortex involved in language and perception for permanent storage.

There is no universal acceptance of a distinction between short-term memory and long-term memory. However, clinical evidence from patients suffering from Korsakoff's syndrome (where chronic alcoholism produces both retrograde anterograde amnesia) or from severe head injury shows that short term memory in such occasions is severely impaired while the long-term memory remains intact.

It is to be remembered that even though short-term memory and long-term memory are conceptually different from one another, they are highly interdependent. Rehearsal in STM leads to memories in LTM and LTM is necessary STM encoding.