MEMORY

MEMORY

MEMORY

There are three stages in memory:

1. Encoding – The information is translated into a form that the brain understands and can store.

2. Storage – The information is then held in the memory.

3. Retrieval – Getting the information from the MEMORY store, ready to use.

Encoding, storage and retrieval can be helped by:
1. State or context dependent learning – if we learn something in a particular physiological or emotional state we are more likely to remember it when we return to that state. Overton showed how people who were drunk when they learnt something could remember it best when drunk again! Also, if you are in a certain place when you learn something you will remember it again when you are in that place. The context here is giving us clues. In a study on divers one group were asked to memorise a list of words on the beach and one under the water. When they were asked to remember the words the groups were divided with half the divers recalling where they learnt the information and the other half where they hadn’t ( on the beach or under the water). Those who recalled in the same environment recalled 40% more than those recalling in a different environment. Context seems to improve retrieval of information.

2. Cues – cues like mnemonics, context or organisation can all help us to remember. Tulving & Pearlstone gave two groups of participants lists of words to remember. These lists were arranged in sets with a heading. On recall one group was given a sheet of paper with the headings on it and the other was given a blank sheet of paper. The group who had been given the headings (i.e. the cues) remembered far more than those weren’t. Mnemonics also work in this way.

3. Organisation – this makes the retrieval of information easier. Bower asked participants to learn 112 geological terms. One group had the terms arranged into a true hierarchy and one group had them arranged randomly into a hierarchy. Those who had the true hierarchy recalled far more of the words than those with the random hierarchy. Thus organising materials in a meaningful way helps to improve memory.



In the 19th century Ebbinghaus investigated MEMORY by using lists of nonsense syllables and found that the amount of rehearsal was important to how well something is remembered.
He listed different kinds of testing MEMORY including:
1. Free Recall with no special instructions in any order.
2. Cued Recall where help is given and the item is associated with a cue.
3. Recognition where identification of something originally seen is necessary out of all the information presented.

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Theories of Memory

There are three theories:

1. The Multistore model (Atkinson –Shiffrin) which suggests there are two memory systems Short-term memory (STM) for events occurring in the immediate past (30 seconds or so) and Long-term memory (LTM) for the rest of our past.
STM has a limited capacity and is thought to code information on the basis of sounds. LTM is extensive and codes information by meaning.
Information in the Short-term memory is transferred to the Long-term memory for more permanent storage using rehearsal.
STM’s capacity has been described as “the magical number 7 plus or minus 2”(Miller). This can be increased by chunking. Chunking also gives meaning to the information which means that it will be more likely to be remembered.
Support for this theory comes from experiments on the primacy-recency effect and on rehearsal:
Murdock found that the participants recalled items from the end and the beginning of lists and forgot those from the middle. The idea here is that the words at the end (recency) are being retrieved from the STM and those from the beginning (primacy) from LTM.
Peterson et al gave participants short series of letters (CPQ etc) and then asked them to count backwards in threes. This interfered with rehearsal and resulted in most of the material being forgotten. It seems that rehearsal is needed to retain information in the STM and also transfer it to LTM.
The problems with this theory are that other studies show that rehearsal doesn’t always improve memory and also it is questionable whether memory is really divided into compartments.


2. Craik and Lockhart’s levels of processing model. This states that how well we remember information depends on how well we have ‘processed’ it.
Rehearsal does not necessarily result in better memory but giving meaning to words deepened the processing and results in better recall. This is known as ‘elaboration rehearsal’. (see also mnemonics below) Maintenance rehearsal is where words are only processed at a superficial, shallow level. Craik and Lockhart gave participants lists of words with questions about each word, e.g. is the word in capitals (shallow, visual processing); does the word rhyme with…(moderate, phonetic processing); fit the word into a sentence (deep, meaningful processing). Participants remembered more words from the third group (deeper processing). It has also been found that there was no difference whether or no the participants were expecting a memory test.
This theory does take into account how well the item is learnt in the first place and is supported by evidence from the work of Bartlett and others. However, it is hard to define ‘depth’ of processing and other researchers have found that maintenance rehearsal can also improve memory.


3. Constructive memory - Bartlett examined memory in a more realistic way by
asking participants to repeat a story he told them called ‘The War of the Ghosts’ to other people. This story is about a battle between two Indian tribes, one side of which is made up of ghosts. Bartlett found that participants altered some parts of the story to fit in with their own beliefs and ideas. He called this “effort after meaning”. This shows that memory is an active process which involves the reconstruction of events and can be affected also by feelings.
This theory does allow us to relate memory to everyday life but the story used is ambiguous and not like our usual experience.



Applications of memory research and ways to improve memory
All these theories of memory l us how to improve our memories in different ways. The Atkinson – Shiffrin model would suggest that rehearsal (i.e. revision) helps us to remember things better. The Levels of Processing model suggests on the other hand that giving information meaning (i.e. understanding what you are trying to learn) will help us to remember it.
Mnemonics are another way of improving memory. A mnemonic is an aid to memory. We can help store and recall information using visual and verbal systems, for example one visual mnemonics is the method of loci – we imagine going on a familiar walk and place the items to be remembered along the way e.g. potatoes in the tree. It is important to visualise bizarre images. When you need to remember the information then you visualise/imagine going on the walk again and seeing the items as you go. Examples of verbal mnemonics are rhymes (e.g. 30 days hath September…) or making a set of words from the first letter of words to be remembered e.g. Richard Of York Gave Battle In Vain (ROYGBIV – order of the colours of the rainbow – red, orange, yellow, green, blue, indigo, violet).

Explanations/Theories of Forgetting:

1. Motivated Forgetting – Freud suggests that we repress unpleasant feelings and events in the unconscious mind.
2. Brain damage or disease can lead to amnesia. Retrograde amnesia is loss of memory before an event. Anterograde amnesia is loss of memory after an event. One study on American footballers who had suffered concussion during a game found that they could recall what had happened to them as soon as they gained consciousness but could not recall this when asked again twenty minutes later. It was concluded that they had not transferred the information from STM to LTM
3. Interference – new incoming material interferes with material already in the memory and vice-versa. In one study participants were asked to learn a list of paired words. Half of them were then asked to learn a second paired list. On recall of the first list the group who only learnt the first list were more accurate than those who learnt both. The second list seemed to be interfering with recall of the first list. This is called retroactive interference. The opposite can also happen i.e. the first/earlier list can interfere with recall of the second or later list. This is called proactive interference.
4. Memory traces can decay over time. Memories make tiny changes in the brain and rehearsal must be used to prevent this trace fading with time. See study above on the footballers.

Eye-witness Testimony

Loftus and Palmer (1974) showed participants a film involving a road accident and asked them to estimate the speed of the vehicles involved. If the verb used in the question was “hit”, the average speed was estimated at 31 mph, if “smashed” then 41mph. A week later 32% of subjects who heard the word “smashed” said there was glass present while only 14% who heard the word “hit” did.
Loftus has said that we alter information for a number of reasons: because of our own beliefs or prejudice or because of suggestions made to us. This fits in with Bartlett’s research (see above) showing that many factors can affect the reliability of memory. This highlights the dangers of leading questions, for example in court. However Loftus (1979) has also shown that more important events are not so likely to be so influenced. In an experiment where participants were shown a man stealing a red purse subjects could accuray report the colour even when told it was brown.
Criticisms of these experiments:
It may be that participants think they should overestimate speed because it is expected, i.e. “demand characteristics”. Other experiments have shown that memory for the original event does not change as Loftus suggests. Even when
they have been misled their original memory remains. Neutral questions seem to be important.
Factors involved in eye-witness testimony:
1. Leading questions – see above
2. Emotion – studies by Loftus have found that people’s memory for faces is less accurate when there is a weapon involved. Witnesses seem to focus on the weapon not the face of the criminal.
3. Context – see divers’ study above. The police now help the witnesses to recreate a similar context (by e.g. imagining what they were wearing and their mental state) and thus improve their recall.