FORGETTINGAND

THEORIES OF FORGETTING

FORGETTING

FORGETTING Forgetting refers to the inability to

retrieve previously stored information.

When you forget something it means that it is unavailable to you at the time you are trying to remember it, not that it is gone forever.

The information may be stored in your memory but for some reason you cannot retrieve it when you want to.

Forgetting is supposed to occur when the information in LTM decays due to passage of time or due to interference from other material or due to the time elapsed

THE FORGETTING CURVE A forgetting curve shows the pattern

(rate and amount) of forgetting that occurs over time.

Generally this curve shows that forgetting is rapid at first, then the rate of memory loss gradually declines as time passes.

More than half of the memory loss occurs within the first hour after learning.

THE FORGETTING CURVE You can see

that over half of what is learnt is forgotten in the first hour

Most of what we forget (about 65% ) is lost in the first 8 hours

THEORIES OF FORGETTING Psychologists have developed a

number of theories to explain why we forget.

Forgetting may occur because:

The right retrieval cue is not used.There is interference from competing

material.There is some underlying motivation not

to remember.Memory fades through disuse.

RETRIEVAL FAILURE THEORY(LTM) Retrieval Failure Theory refers to

when we forget because we lack or fail to use the right cues or prompts to retrieve what is stored in our memory.

This theory is often referred to as cue-dependent forgetting and is a useful explanation of why we sometimes fail to retrieve information even when we’re sure we know the information.

RETRIEVAL FAILURE THEORY (LTM) Retrieval failure is where the information is in long

term memory, but cannot be accessed.  Such information is said to be available (i.e. it is still stored) but not accessible (i.e. it cannot be retrieved). It cannot be accessed because the retrieval cues are not present.  When we store a new memory we also store information about the situation and these are known as retrieval cues.  When we come into the same situation again, these retrieval cues can trigger the memory of the situation. Retrieval cues can be:

External / Context - in the environment, e.g. smell, place etc.

Internal / State- inside of us, e.g. physical, emotional, mood, drunk etc.

TIP OF THE TONGUE PHENOMENON Have you ever tried to recall a fact –

perhaps the name of an actor in a movie – that you’re sure you know and feel just on the verge of remembering?

You know that you know the answer but can not quite bring it forth.

Psychologists call this the tip-of-the-tongue phenomenon.

TIP OF THE TONGUE PHENOMENON Tip-of-the-tongue (TOT) is a state, or

‘feeling’, that occurs when individuals are aware of knowing something, confident they will eventually remember it, but aren’t able to retrieve it from memory at that point in time.

When the sought after information is recalled, its recall tends to occur suddenly, often seeming to ‘pop’ out of memory.

TIP OF THE TONGUE PHENOMENON The apparent gap in memory which

occurs in a TOT state is particularly intriguing because even though we can’t say the word, we have some information about the word we want;

For example we can often tell how many syllables it has, the beginning and ending letters, or what it rhymes with.

We can also eliminate words that don’t sound right or are incorrect.

TIP OF THE TONGUE PHENOMENON These observations suggest that TOT

involves a partial retrieval process in which bits of information can act as retrieval cues for the required information, helping to ‘home in’ on this information.

Furthermore, the observation that specific bits or types of information assist in retrieval indicates information in LTM is stored in an organised way and in a variety of forms.

TIP OF THE TONGUE PHENOMENON The TOT phenomenon is significant

because it illustrates several aspects of the retrieval process.

First it shows that retrieving is not an all-or-nothing process.

Second, information is stored in LTM but it is not accessible without retrieval cues.

Third, TOT experiences indicate that information stored in LTM is organised and connected in relatively logical ways.

DECAY THEORY(STM & LTM) Decay theory is based on an

assumption that when something new is learned, a physical change or chemical trace of the experience which contains the stored information is formed in the brain.

This is called memory trace and is believed to gradually fade or disintegrate as time passes unless it is reactivated by being used again.

CLASSIC SHAPE OF THE FORGETTING CURVE (WOODWORTH, 1938).

TRACE DECAY THEORY(STM & LTM)

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 Heb 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.

TRACE DECAY THEORY(STM & LTM) 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. 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.

TRACE DECAY THEORY(STM & LTM) .  Decay theory suggest that we forget

something because the memory 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.  Thus, this theory suggests that memories are not permanent.      There are other theories of forgetting.  Memory for an event may reflect interference. The interference theory of forgetting suggest that we would forget something because other information learned is interfering with our ability to recall it.  

TRACE DECAY THEORY(STM & LTM)       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.  Perhaps it is still there but we cannot retrieve the memory for some reason.

CONCLUSIONS OF DECAY

1)  Shape of the forgetting curve is greatly influenced by the activities during the retention interval.

2)  The logarithmic function does not hold for autobiographical memories.

3)  Therefore, there is little evidence that decay is the primary cause of loss of information from long-term memory.

CONCLUSIONS ON FORGETTING

Four different explanations: decay: minimal role in LTS

forgetting consolidation: disruption occurs

under special circumstances interference theory: explains some

forgetting, but the mechanisms need work

retrieval failure: richest, most complete explanation, but may be circular.