Page "Forgetting" Paragraph 7

Trace decay theory explains memories that are stored in both short term and long term memory system.

According to this theory, short term memory ( STM ) can only retain information for a limited amount of time, around 15 to 30 seconds unless it is rehearsed.

If it is not rehearsed, the information will start to gradually fade away and decay.

Donald Hebb proposed that incoming information causes a series of neurons to create a neurological memory trace in the brain which would result in change in the morphological and / or chemical changes in the brain and would fade with time.

Repeated firing causes a structural change in the synapses.

Rehearsal of repeated firing maintains the memory in STM until a structural change is made.

Therefore, forgetting happens as a result of automatic fading of the memory trace in brain.

This theory states that the events between learning and recall have no effects on recall ; the important factor that affects is the duration that the information has been retained.

Hence, as longer time passes more of traces are subject to decay and as a result the information is forgotten.