Memory

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Multi Store Model

Multi store model- a representation of how memory works in terms of three stores called sensory register, short term memory and long term memory. It also describes how information is transferred from one store to another

It was created by Richard Atkinson and Richard Shriffin' and consists of 4 parts. Sensory information, sensory register, STM and LTM

Sensory register

A stimulus from the environment will pass into the sensory registers. The two main stores are called ionic and echoic

iconic memory is where visual information is coded

echoic memory is where sound or auditory information is coded acoustically

The sensory registers have a high capacity however has only a duration of less than half a second.

For information to pass from the sensory register to a memory store attention must be paid to it

Short term memory (STM)

known as the limited capacity store because it can only contain a certain number of things before forgetting takes place.

Capacity averages between 5 and 9 items of information.

Maintenance rehearsal occurs when we repeat material to ourselves over and over again. We can keep information in our short term memory if we rehearse it and when we rehearse it for long enough it passes into our LTM

Long term memory (LTM)

This is the permanent memory store for information that has been rehearsed for a prolonged period of time.

Psychologists believe that its capacity is unlimited and last for many years.

LTM tends to be coded semantically

When we want to recall a memory from the LTM is has to be transferred back into STM by the process called retrieval.

Strengths of the multi store model

supported by research studies- These show that STM and LTM are different and independent memory stores. An example of a study is Baddelys research on coding as it shows the two memory stores are coded differently and therefore withhold independent information

Limitations of the multi store model

There is evidence that there is more than one STM which goes against the MSM. There is evidence from people with amnesia. For example the investigation by Shallice and Warrington that concluded his recall of digits was better when he read them to himself compared to when they were read aloud to him. This suggest there are different kinds of STM that withhold different types of information

There is more than one type of rehearsal- According to the MSM the more you rehearse something the more likely you are to transfer it to LTM. Craik and Watson argue this as they say it is the type of rehearsal that matters. They recovered there are two types of rehearsal

Elaborative rehearsal- this occurs when you link existing knowledge to the information you are taking In- This is the rehearsal needed for long term storage

Maintenance rehearsal- when you repeat information over and over- this is used to maintain information in the STM

Artificial materials- to study memory artificial material is used meaning the findings may not relate directly to real life

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Types of LTM

Endel Tulving proposed there were three types of LTM

Episodic memory- A long term memory store for personal events

Semantic memory- A long term memory store for our knowledge of the world

Procedural memory- A long term memory store for our knowledge of how to do things

Episodic Memory

First these memorys are time stamped so we can recall when they occured

Then individual factors of the memory will be categorized such as who you were with, objects around you and place

Thirdly, you have to make a concious effort to recall these memorys, you know you are searching for a memory

Semantic Memory

These memorys are not time stamped

Semantic knowledge is less personal and more about facts we all share

This knowledge is continously getting added to as we grow and experience specific events in our life

Procedural Memory

We can recall these memories without concious awareness or a great deal of effort

We find this information hard to recall to others as it is so natural to us

Strengths of the idea of three types of LTM

Clinical evidence- HM and clive wearing studied two individuals ho were severly impaired as a consequence of Amnesia. They found that events were hard to recall however semantic memorys were relatively unaffected. Their procedural memories were also intact. This evidence supports Tulvings view that there are different types of memory stores in LTM.

Neuroimaging evidence- Tulving got participants to perform various memory tasks whilst their brains were scanned using a PET scanner. They found that episodic and semantic memories were found in the prefrontal cortex which is divided into two sides. left- semantic and right- episodic. This is a strength as it supports the view there is a physical reality to the different types of LTM, within the brain. It has also been backed up in further research studies therefore increasing validity

Real life applications- Being able to identify different aspects of the LTM allows psychologists to target certain kinds of memory in order to better peoples lives eg train their brain to allow it to develop and improve memory.

Limitations of the idea of three LTM

Problems with clinical evidence- there is a lack of control of all sorts of different variables that may also affect memory therefore decreasing reliabilty of the studys

Three types of LTM or two - Cohen and Squire disagree with Tulvings division of LTM into three types. They accept that procedural memories represent one type of LTM but argue that episodic and semantic memories are stored together in an LTM store called declorative memory and procedural memories are stored in non-declaritive

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Memory studies- process and evaluation

Coding, Capacity and Duration

CODING- Alan Baddeley

Procedure- he gave different lists of words to four groups of participants to remember.

acoustically similar (words that sound similar)

acoustically dissimilar (words that sound different)

semantically similar (words with similar meanings)

semantically dissimilar (words with different meanings)

Participants were shown the original words and asked to recall them in the correct order.

Findings -When they had to recall immediatley after they tended to do worse with acoustically similar words showing STM is coded acoustically

When participants had to recall twenty minutes after the test they did worse with semantically similar words showing LTM is coded semantically

EVALUATION- it was artificial stimuli used rather than meaningful material. This means we should be cautious about generalising the findings therefore the study overall has limited application

CAPACITY- Joseph Jacobs

procedure- he developed a technique to measure digit span. The researcher gives, for example, four digits and then the participant is asked to recall these in the correct order out loud. If this is correct the researcher will read out 5 digits and so on until the participant cannot recall the correct order. This determines the digit span.

Findings- He found the mean digit span was 9.3 items and the mean span for letters was 7.3

EVALUATION- A limitation of Jacobs study is that it was conducted a long time ago. Early research often lacked adequte control which could lead to the results not being valid because cofounding variables were not controlled. However, his results had been confirmed in other research therefore supporting its validity.

CAPACITY- George Miller

procedure- made observations of everyday practise. He noted things came in sevens which suggested STM capacity is around 7 items. However miller also noted that people could recall 5 letters just as well as they could recall 5 words. The idea was they did this by chunking- grouping sets of digits or letters in chunks

EVALUATION- he may of overestimated the capacity of the STM. Other studys have shown the capacity of STM was only 4 chunks. This suggest that the lower end of millers research (5) was more appropriate than 7 items.

DURATION- Margaret and Lloyd Peterson

procedure- 24 undergrauate students were tested. Each student took part in 8 trials; on each trial the student was given a consonant syllable to remember and was also given a 3 digit number to recall backwards until told to stop. This was to prevent any rehearsal of the consonant syllabule. On each trial they would stop counting after a different amount of time and the asked to recall the syllabules.

Findings- as the retention interval increased the % of correct responses decreased. This shows the STM has a short duration

EVALUATION- the stimulus material was artificial. Trying to memorise syllables does not represent real life memory activities meaning the study lacks eternal validity.

DURATION-Harry Bahrick and colleagues

procedure- they studied 392 participants from the american state of Ohio who were aged between 17 and 74. High school yearbooks were obtained from the participants or directly from schools. Recall was tested in two ways

free recall where they named as much people as possible who were part of their graduating class

photo recognition- consisting of 50 photos some from the participants year book

Findings- participants who were tested within 15 years of graduation were about 90% accurate in photo recognition; after 48 years this accurate recall was only 70%. Free recall was less good than recognition. after 15 years this was about 60% accurate dropping to 30% after 48 years. This shows LTM can last a long time

EVALUATION- it has high external validity as real- meaningful memories were studied. The issue with such real life research is that cofounding variables are not controlled eg the fact they may have looked at the yearbooks over the years

Interference

There is the idea that interference is worse when the memories are similar

EFFECTS OF SIMILARITY- John McGeoch and William McDonald

procedure- studied retroactive interference by changing the amount of similarity between two sets of materials Participants had to learn a list of words until they could remember them with 100% accuracy. They then learned a new list. There were six groups who had to learn different types of lists

synonyms- words with same meaning as original

antonyms- words with opposite meaning to original

words unrelated to original

nonsense syllables

three digit numbers

no new list - rested

Findings- when participants recalled the original list of words recall depended on the nature of the second list. The most similar material produced the worst recall. This shows interference is stronger when the memories are similar

EVALUATION- Artificial material used- there is more chance interference will occur in a lab compared to in a real life situation. The material used is not things we learn in everyday life meaning interference findings from lab studies may not be an accurate representation of interference in everyday memory tasks.

This is a lab study meaning cofounding and extraneous variables are controlled. This is a strength as it increases the validity of the findings.

Retrieval failure theory

Retrieval failure- a form of forgetting- it occurs when we don't have the necessary cues to access a memory. The memory is available but not accessible

CONTEXT DEPENDENT FORGETTING- Duncan Godden and Alan Baddeley

Procedure- carried out an investigation of the sea divers working underwater. The divers learned a list of words and then were asked to recall them either underwater or on land. This created four conditions

learn on land- recall on land

learn on land- recall underwater

learn underwater- recall on land

learn underwater- recall underwater

Findings- in two of these conditions the environmental contexts of learning and recall matched whereas in the other they didn't. Accurate recall was 40% lower in the non matching conditions. The external cues available at learning were not available at recall and this led to retrieval failure

STATE DEPENDENT FORGETTING- Sara Carter and Helen Cassaday

Procedure- gave anti histamine drugs to participants. They had a mild sedative that made them a little drowsy. The participants had a list of words and passages of prose and hen recall the information again creating conditions

learn on drug- recall when on it

learn on it- recall when not on it

learn not on it- recall when on it

learn not on it- recall not on it

findings- when there was a difference between learning and recall the performance on memory test was worse. When cues were absent forgetting occurred

EVALUATION OF BOTH- questioning context effects- it is said that contexts have to be very different before an effect is seen . This is a limitation because real lie applications of retrieval failure don't actually explain much forgetting.

Supporting evidence- There are other studies that have proved the same conclusions as the studies above. This increases validity of the explanations

recall versus recognition- in Baddelys study the diver were asked to recognise words instead of recall them. This is a limitation as it means the presence of cues only affect memory when you test it in a certain way

Factors affecting eye witness testimony

Misleading information- this can occur through post event discussion and leading questions

LEADING QUESTIONS- Elizabeth Loftus and John Palmer

procedure- arranged for participants to watch film clips of car accidents and then gave them questions about the accident. In the critical question participants were asked to describe how fast the car was going when they ".." each other. There were 5 groups and each were given a different verb (hit, contacted, collided, smashed and bumped"

findings - The mean estimated speed was calculated for each participant group. The verb contacted resulted in a mean estimated speed of 31.8mph however the word smashed had a mean speed of 40.5 mph.

POST EVENT DISCUSSION- Fiona Gabbert and collegues

procedure- studied participants in pairs. each participant watched a video of the same crime but filmed from different points of view meaning they could see element that the other couldnt. Both participants then discussed what they had seen before individually completing a test of recall

Findings- 71% of participants mistakenly recalled aspects of the event that they did not see but had picked up in the discussion. The corresponding figure in a control group where there was no discussion was 0%. They concluded individuals go along with others because they believe the others are right

EVALUATION OF BOTH- useful real life applications- It has hugely important practical uses where the consequences of EWT are high, It allows police to adapt techniques that allow misleading information to be decreased. For example they could come up with questions beforehand so they can ensure they are not leading in anyway

Tasks are artificial- in both these tasks individuals are watching incidents on a film. This means some factors that affect memory in real life events such as anxiety are not considered in the final conclusion from the experiments Therefore the results may not be an accurate representation of accuracy of EWT

Individual differences- There is evidence that older people are worse at accurate recall than younger. However, due to old age bias it is proven that individuals are more succesful at identifying when the man they are identifying is around the same age group. In most studies younger indivisuals are used therefore making it hard to generalise the findings to everyone

Demand characteristics- individuals may act in a specific way or tell researchers specific things because they think that is what is expected. If they dont know the answer they may guess. Also when watching the film they may have taken a guess at what they will have to do after meaning they may pay more attention to the incident compared to what they would in real life

Factors affecting eye witness testimony (anxiety)

ANXIETY HAS A NEGATIVE EFFECT ON REALL- Johnson and Scott

procedure- They led participants to believe they would be taking part in a lab study. Whilst they were seated in the waiting room and heard an argument in the next room. In the low anxiety conditions a man then walked through the wating area holding a pen and had grease on his hands. Others heard the same heated argument however was accompinied by the sound of breaking glass. A man walked out of the room with a paper knife that was covered in blood. this was a high anxiety condition

Findings- the participants later picked out the man who was carrying the item in each the low anxiety condition and the high anxiety condition. 49% could identify the man holding the pen however only 33% could recall the man who was holding the knife. This is due to the tunnel theory which suggests you focus on the weapon instead of the individual holding it as the weapon is the source of anxiety

ANXIETY HAS A POSITIVE EFFECT ON RECALL- John Yuille and Judith Cutshall.

procedure- they conducted a study on a real life incident where the shop owner shot a thief dead. The interview took place 4-5 months after the incident and were compared to notes made from the original interview. Accuracy was determined by the number of details reported in each account. They were also asked how stressed they are out of 7.

findings- the witnesses are very accurate in their accounts and there was little change in the amount of accuracy after 5 months- those participants who reported the highest levels of stress were most accurate. 88% compared to 75%

EVALUATION FOR BOTH- weapon focus may not be relevant. They may focus on the weapon as it is a surprise they are seeing it not due to the tunnel theory. This therefore doesnt specifically tell us anything about effects of anxiety on EWT.

field studies lack control- some things may have happened in the meantime that researchers have no control over eg accounts they may have read on the media that gave them extra information. These may be the reason for accuracy of recall.

there are ethical issues- it has potentiol to subject people to psychological harm purely for urposes of research. Benfits of research may outweigh problems