The information was never stored – problem of availability
The information was stored, but is difficult to retrieve – problem of accessibility (tip-of-the-tongue)
Confusion – problem of interference
Absentmindedness – problem of habit, attention, and automatic responses.
Generally, forgetting is the inability to recall or recognise material which was previously stored in memory.
Forgetting in STM
What is trace decay theory?
Information is forgotten because of the passage of time.
What evidence supports this theory?
Peterson and Peterson, (1959) found that memories were held in short-term memory for approximately 18-30 seconds, after which they disappeared via trace decay.
How can the theory be explained?
Hebb (1949) believed that, as a result of excitation of the nerve cells, a brief memory trace is laid down. At this stage the trace is very fragile and likely to be disrupted.
With repeated neural activity (via rehearsal), a permanent structural change occurs and the memory is transferred to the long-term memory where it is no longer likely to decay.
Displacement refers to the limited number of slots in short-term memory (7+/-2).
When more items are introduced into short-term memory than there are slots, some of the old information must be knocked out of its slot, or ‘ d isplaced’ .
Evidence for this comes from the Brown-Peterson technique, where the last few words on a list are displaced from short-term memory by the counting task.
The idea behind this theory is that memories may be interfered with either by what has been learned before, or by what may be learned in the future.
Forgetting increases with time because of interference from competing memories that have been acquired over time.
Diversion of Attention
If attention is diverted away from the information to be retained, it is more likely to be forgotten.
Lack of Consolidation
It seems that a period of consolidation is necessary for material to be firmly recorded in the long-term memory.
Damage to the brain causes a variety of effects on performance.
Forgetting in LTM
Memory may be lost from the long-term memory in the form of decay through disuse.
The idea is that knowledge and skills that have not been used for a long time will eventually fade away.
This occurs, when new information interferes with the recall of old information.
Retroactive interference was widely studied in the 1960s, but has attracted less attention since then.
Such studies typically made use of the technique of paired-associates in which a word is associated with one word on a list and with a completely different word on another list.
Participants are required to learn one list and then the other.
When given the stimulus word from the first list, it was found that participants frequently suffered from retroactive interference: they recalled the paired associate from the second list.
This occurs when old information interferes with the recall of new information.
Underwood (1957) noted that students who had learned a list of nonsense syllables showed a greater rate of forgetting when tested after 24 hours than would be expected.
In both cases of interference, the greater the similarity of the interfering material, the greater the interference.
I’m going to be a couple of minutes late. Please do this while you’re waiting:
Without looking in your notes or textbooks. Write down as much as you can remember about the theories of forgetting we’ve already covered.
Once you’ve done all you can look at the books/notes to see what you forgot.
Can you explain why you forgot?
What could you do to help you remember?
This refers to two related phenomena:
research (eg Abernathy, 1940) has shown that it is much easier to remember information in the same context in which the information was learnt.
also remembering information is made easier with retrieval cues which trigger memory for relevant information.
research (eg Goodwin et al, 1969) showed that information is more likely to be remembered by an individual if they are in the same physical or emotional state as they were in when they learned it.
Victims of concussion or brain injury, or patients who undergo brain surgery or electro-convulsive therapy (ECT) often suffer from retrograde amnesia - loss of memory for events which have occurred prior to injury/treatment.
Korsakov syndrome, which is the result of advanced alcoholism causes anterograde amnesia - the loss of memory for new information.
There may be memories that you want to forget and not conjure up.
Freud (1915) proposed that forgetting is motivated by the desire to avoid displeasure, so embarrassing, unpleasant or anxiety-producing experiences are repressed – pushed down into the unconscious.
Repression is an unconscious, protective defence mechanism, which involves the ego actively blocking the conscious recall of memories – which become inaccessible.
Key Study: Levinger and Clark (1961)
Repression is, however, difficult to prove conclusively.
The term ‘flashbulb memory’ describes a long-lasting vivid memory formed at a time of intense emotion, such as significant public or personal events.
Some argue that a flashbulb memory ia a special and distinct form of memory since the emotionally important event triggers a neural mechanism, which causes it to be especially well imprinted into memory.
Others disagree since the long-lasting nature of the memory is probably due to it being frequently rehearsed (thought about it and discarded afterwards) rather than being due to any special neural activity at the time.
Key Study: McCloskey et al. (1988)
Make sure your notes on forgetting are up to date.
Complete the questions on page 28 of the AS textbook.
Memory Improvement Techniques
Improving the memory depends on organising information and then using active techniques and persevering with them.
Organising and ordering information can significantly improve memory.
By Category and Hierarchy
By Category and Hierarchy
If things are stored away in their proper place it is much easier to find them than when they are jumbled up.
Memory is the same, retrieval is made easier when memory is organised rather than if it is disorganised.
Information can be accessed if it is organised by category and hierarchy.
The limited capacity of short-term memory, can also be assisted by organising the information into chunks (ref. Miller 1956).
graphically verbal rose
Diagrams can be used to illustrate information and to aid understanding of information.
Imagery can be defined as the creation of a mental picture.
After studying patients with damage to one of their temporal lobes, Paivio (1971) proposed that the processing of words and images occurs separately.
According to Paivio, concrete words, which can be images, are encoded twice in memory, once in verbal symbols and once as image-based symbols. This increases the likelihood that they will be remembered.
Paivio called this the dual coding hypothesis. (This can be linked to the phonological loop in the working memory model.)
It is easier to retrieve a particular episode if you are in the same context as that in which the episode occurred.
Godden and Baddeley (1975) presented divers with material to learn, either on dry land or underwater. Subsequent retrieval was best when the recall environment matched that of the original learning.
Active learning facilitates memory by helping an individual to attend to and process information.
‘ Practice makes perfect’ – the more times information is memorised, the more accurate the recall and the less time it takes to re-learn the material.
Ebbinghaus (1895) found re-learning savings – the greater the number of repetitions the less time it took to re-learn the lists.
Linto found that everyday memories last longer if they are occasionally remembered.
Mnemonics try to improve organisation when encoding takes place.
They are a combination of loci, associations and imagery.
Grouping – classify lists on the basis of some common characteristic. Remembering the key element of the group is a key to remembering all the items. An example would be grouping trees by deciduous or evergreen.
Rhymes – setting the information to be remembered to a rhyme eg ‘in 1492 Columbus sailed the ocean blue’. What are some other examples of mnemonics using rhyming? It seems that the rhythmic pattern helps by reducing the number of retrieval possibilities.
Acronyms – the first letter from each word in a list forms a key word, name, or sentence,
eg ‘Richard of York gave battle in vain’ for the colours of the spectrum or ‘every good boy deserves food’ for the lines on the treble clef.
Chaining material to be learned into narrative stories can also help remembering.
Bower and Clark (1969) asked participants to make stories from lists of ten un-related nouns.
Subsequently, 93% showed correct recall.
Mnemonics help memory by shortening the sequence to be learned or elaborating it, and giving it meaning.
They do have drawbacks:
they do not help to understand the material
they are time consuming to learn
under stress the mnemonic may be forgotten and therefore the information.
Mind mapping involves writing down a central idea and thinking up new and related ideas out from the centre.
By focussing on key ideas written down and then looking for branches out and connections between the ideas, knowledge is mapped in a manner which will aid learning and recall.