Theories of forgetting

THEORIES OF FORGETTING

1.Retrieval Failure Theory :

Retrieval due to absence of cues is sometimes also called cue-dependent forgetting.

This theory explains why we cannot recall from long term memory and also why forgetting in long term memory is due to a lack of access to a memory rather than the availability of a memory.

The suggestion is that internal (such as mood state) and external (such as temperature and smell) cues can help facilitate recall of a long term memory.

According to Tulving, forgetting occurs when the right cue is not available for retrieving the memory.

When a memory is encoded it leaves a memory trace (also called engram) which also stores information about the way we felt or the place we were in at the time of encoding. In order for this memory to be accessed again a retrieval cue is required. The greater the similarity between the encoding event and the retrieval event, the greater is the likelihood of recalling the original memory ( Called encoding specificity principle).

There are 2 types of cue that can aid recall –

A.   Context - Context cues mean that if we are not in the same place as we were when learning, the memory may not be accessible.

B.    State- State cues mean that if we are not in the same physical and emotional state as we were when the learning happened, we may not be able to access the memory

2.Theory Of Motivated Forgetting

The motivated forgetting theory was invented by Sigmund Freud. According to Freud (1901), forgetting is motivated rather than being the result of a failure to learn or other processes.

Motivated forgetting arises from strong motive or desire to forget, usually because the experience is too disturbing or upsetting to remember.
The two types of motivated forgetting are :

A. Repression (unconsciously) - The concept of forgetting ones feeling unconsciously.

B. Suppression (consciously)- Forgetting one's thoughts and memories consciously.

According to this theory, some memories are so painful or upsetting that thinking about them would produce overwhelming anxiety. Instead, they are repressed (pushed below conscious awareness) and so become inaccessible. This is a form of self-defence.

Memories that are likely to induce guilt, embarrassment, shame or anxiety are actively, but unconsciously, pushed out of consciousness as a form of ego defence.

 Unconscious or repressed memories are exceedingly difficult to retrieve but remain available. They continue to exert a great influence over us, even though we have no awareness of them.

It is widely accepted that repression plays a crucial role in different types of psychogenic amnesia.

 3. Trace Decay Theory of Forgetting

This explanation of forgetting in short term memory assumes that memories leave a trace in the brain and suggest that we forget something because the memory trace of it fades with time.  This theory would suggest that if we do not attempt to recall an event, the greater the time since the event the more likely we would be to

forget the event.

Trace decay refers to apparent loss of information already encoded and stored in an individual's long term memory. It is often a gradual process in which old memories are unable to be recalled from memory storage

A trace is some form of physical and/or chemical change in the nervous system.

When we learn something new, a neurochemical “memory trace” is

created. However, over time this trace slowly disintegrates. It is widely believed that neurons die off gradually as we age, yet some older memories can be stronger than most recent memories. Thus, decay theory mostly affects the short-term memory system, meaning that older memories (in long-term memory) are often more resistant to shocks or physical attacks on the brain.

 This theory suggests short term memory can only hold information for between 15 and 30 seconds unless it is rehearsed. After this time the information / trace decays and fades away.

This theory is popular because it appears to fit with common-sense views of the way memory works. One of the most influential attempts to explain forgetting in terms of decay was by Hebb (1949).

One problem with the decay theory of forgetting is that we do not know whether the failure to recall something reflects that it is no longer in our memory, or that it reflects retrieval failure.  

4. The interference theory of forgetting

This theory states that forgetting can be caused by two competing memories. The basic theory states that interference occurs when information that is similar in format gets in the way of the information that someone is trying to recall.

There are two types of interference:

A. Retroactive interference - Occurs when new information interferes with the retrieval of old information

B. Proactive interference occurs when old information interferes with the retrieval of new information.

Interference is an explanation for forgetting in long term memory.

Weaknesses of the theory is that this theory only can explain lack of recall when information in a similar format prevents recall. This means that there are many types of recall that are not explained by this theory.

5. The Gestalt Theory of Forgetting:

This theory suggests that memories are forgotten through distortion. This is called False Memory Syndrome. Wulf (1922)  states that when memories lack detail, other information is put in to make this memory a whole. However, this causes memories to be changed and not correct.

6. Displacement theory of forgetting

This fits into the multi-store model of memory and is an explanation of why forgetting occurs in STM.

Based on Miller’s famous Magical Number Seven, Plus Or  Minus Two  (his suggestion for the normal capacity of human memory). Short-term memory can only hold a limited  amount of information. Because of its limited capacity, suggested by Miller to be 7+/- 2 items, STM can only hold small amounts of information.

When STM is 'full', new information displaces or 'pushes out’ old information and takes its place.  The old information which is displaced is forgotten in STM.

It was also assumed that the information that had been in the short-term store for the longest was the first to be displaced by new information

This theory explains why information in STM does not always transfer into LTM.

The primacy and recency effect which form part of multi-store model apply to forgetting in STM.

Primacy effect – information learned first will be remembered better due to being transferred to LTM through rehearsal.

Recency effect – The most recent words in the list will have not yet been displaced from short-term memory and so will be free to recall.

Information in the middle will be more likely to be forgotten because it did not go into LTM but was displaced by new information and is forgotten.

7. Incomplete Encoding Theory

This states that incomplete encoding during the rehearsal process in working memory causes an inability to recall information accurately.

The way information is encoded affects the ability to remember it. Processing of information at a deeper level makes it harder to forget. If a student thinks about the meaning of the concepts in her textbook rather than just reading them, she’ll remember them better when the final exam comes around. If the information is not encoded properly it is more likely to be forgotten.

8. Lack of Consolidation theory

In order for information in the STM to become information in the LTM, it must go through a process known as consolidation. Sometimes this process is failed and cause forgetting. 

This theory suggests forgetting has a biological basis.

Memory consolidation is defines as time dependent process by which learned experiences are transformed into long term memory by chemical and structural changes.During consolidation the STM is repeatedly activated.