Editing Forgetting (section)

=== Trace decay theory ===
[[Decay theory]] states that when something new is learned, a neurochemical, physical "memory trace" is formed in the brain and over time this trace tends to disintegrate, unless it is occasionally used. Decay theory states the reason we eventually forget something or an event is because the memory of it fades with time. If we do not attempt to look back at an event, the greater the interval time between the time when the event from happening and the time when we try to remember, the memory will start to fade. Time is the greatest impact in remembering an event.<ref>{{cite web|title=The Decay Theory of Forgetting|url=http://www.psychologyandsociety.com/Decaytheory.html}}</ref>

Trace decay theory explains memories that are stored in both short-term and long-term memory system, and assumes that the memories leave a trace in the brain.<ref name=simply>{{cite web|last=McLeod|first=Saul|title=Forgetting|url=http://www.simplypsychology.org/forgetting.html|publisher=Simply Psychology|access-date=1 May 2014}}</ref> 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 decay 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.

One major problem about this theory is that in real-life situation, the time between encoding a piece of information and recalling it, is going to be filled with all different kinds of events that might happen to the individual. Therefore, it is difficult to conclude that forgetting is a result of only the time duration. It is also important to consider the effectiveness of this theory. Although it seems very plausible, it is about impossible to test. It is difficult to create a situation where there is a blank period of time between presenting the material and recalling it later.<ref name=simply />

This theory is supposedly contradicted by the fact that one is able to ride a bike even after not having done so for decades. "[[Flashbulb memories]]" are another piece of seemingly contradicting evidence. It is believed that certain memories "trace decay" while others do not.{{citation needed|date=May 2021}} Sleep is believed to play a key role in halting trace decay, although the exact mechanism of this is unknown.{{cn|date=September 2023}}

Physical and chemical changes in our brain lead to a memory trace, and this is based on the idea of the trace theory of memory. Information that gets into our short-term memory lasts a few seconds (15–20 seconds), and it fades away if it is not rehearsed or practiced as the neurochemical memory trace disappears rapidly. According to the trace decay theory of forgetting, what occurs between the creation of new memories and the recall of these memories is not influenced by the recall. However, the time between these events (memory formation and recalling) decides whether the information can be kept or forgotten. As there is an inverse correlation that if the time is short, more information can be recalled. On the other hand, if the time is long less information can be recalled or more information will be forgotten. This theory can be criticized for not sharing ideas on how some memories can stay and others can fade, though there was a long time between the formation and recall. Newness to something plays a crucial role in this situation. For instance, people are more likely to recall their very first day abroad than all of the intervening days between it and living there. Emotions also play a crucial role in this situation.<ref>{{cite journal |last1=Ricker |first1=Timothy J. |last2=Vergauwe |first2=Evie |last3=Cowan |first3=Nelson |title=Decay Theory of Immediate Memory: From Brown (1958) to Today (2014) |journal=Quarterly Journal of Experimental Psychology |date=October 2016 |volume=69 |issue=10 |pages=1969–1995 |doi=10.1080/17470218.2014.914546 |pmid=24853316 |pmc=4241183 }}</ref>