AS PSYCHOLOGY

Elizabeth Loftus

Cognitive Psychology:

MemoryName:

Tutor:

Cognitive Psychology: Memory

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What is memory?

• The term memory can refer to the process in which we retain information and knowledge. You may think that this is one process but in fact it is split in to 3 basic processes.

• The first process is called Encoding. This is where a sensory input (e.g. sounds or images) are transformed for it to be registered in memory. Sound, vision and meaning are all encoded differently.

• The second process is Storage. This simply is holding information until it is required.

• The third stage is the process of Retrieval. This is where we locate and use the information we have stored so we are consciously aware of it.

Short Term Memory (STM) and Long Term Memory (LTM)

• Psychologists believe that Short Term Memory and Long Term Memory differ in the amount of information that can be stored, encoded and the duration the information can be held.

• Short Term Memory (STM) is a system for information that you are currently thinking of. Information that is stored here is done so only on a temporary basis.

• Encoding in STM: Psychologists believe that information in STM is mainly encoded acoustically (sound).

• Capacity of STM: The capacity (how much of something can be held) is limited in STM. Only a small amount of information can be held. This can be demonstrated through studies using Serial Digit Span techniques.

• Jacobs in (1887) investigated this. He read allowed a list of either letters or numbers, with one syllable (‘w’ and ‘7’ were excluded). The lists increased until participants could recall them only 50% of the time. A wide age range was used in his sample. He found:

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1. STM capacity for digits was 9, whereas letters was 7.2. STM increased with age.• The conclusion was that STM has a limited capacity of 5-9

digits and age affects STM. This may be due to practice as we get older. Numbers were easier to recall than letters.

• This is supported by Miller (1956) who coined the phrase ‘the magic number seven plus or minus two’ (7+/- 2).

• Criticisms show that practice can affect information recall and also newer research shows people have differing abilities associated with their attention levels.

• Duration of STM: The duration of STM is short. It is less than 30 seconds.

• This is best described by Peterson and Peterson (1959) who used nonsense trigrams (3 letters with no meaning, i.e. WQT). They had to read these and then straight after had to count backwards in 3’s from a large number (e.g. 375). They counted for a specific time period. The participants had specific times in which to recall the trigrams ranging from 3 seconds to 18 seconds.

• The counting was done to stop the retention of the trigrams. • The findings showed that 90% of trigrams were recalled after

a 3 second interval and only 6% after an 18 second interval. • Encoding in LTM: Most psychologists believe that information

is encoded semantically (meaning) in LTM. Baddeley (1966) illustrated this in a study which involved lists of words. List A had acoustically similar words (cat, mat, sad, sat). List B had acoustically dissimilar words such as (pit, day, cow). List C had semantically similar words such as (big, huge, tall). List D had semantically dissimilar words such as (hot, safe, foul).

• After they were given the list they had a 20 minute retention interval where they performed another task.

• This ensured that recall would have to come from LTM. 3

• The list C (semantically similar) was the least well remembered (55%). This seems to suggest there was semantic confusion and this leads to the idea that LTM information is encoded semantically.

• The support for this comes from cognitive sense. In everyday life we can remember the meaning of things but not the words. An example would be a TV programme, you can remember what happened (semantic) but not the exact words (acoustic).

• A criticism of this is that there are different types of LTM. One of these is procedural memory. This includes things such as being able to ride a bike or swim. They aren’t encoded in the same way and are not generally studied. Remembering smells and songs can also be included here.

• The potential capacity of LTM is unlimited. This is because we know that our brains are not full of information on everything. This is why there has been no limit placed on it.

• In LTM the duration lasts as long as you live. You will have memories that you have from childhood that will last until you die. Information in LTM doesn’t have to be rehearsed or repeated. For example you may not have ridden a bike for many years but you can still do it.

• Duration in LTM was demonstrated in a study by Bahrick et al (1975). They gathered 400 participants aged 17-74 years and asked them to remember names of classmates from high school (free recall task). They were also shown a list of

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names and photos. They had to identify their ex-schoolmates (recognition task).

• Those who left school within the previous 15 years recalled 90% of the names and faces in the recognition task. Those who had left within the previous 48 years recalled 80% of names and 70% of faces. These high percentages show we remember names and faces for a very long time.

Table of differences between STM and LTM:

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The M ulti s to r e M od e l

This activity will help you to:• Describe the multistore model of memory• Identifty the hypotheses of the multistore model• Use evidence to assess the multistore model• Evaluate the multistore model

The Multistore Model

Using the sources of information available to you, briefly describe the different components of the multistore model.

The Attention System The Rehearsal Loop

STM LTM

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The Short Term Store The Long Term Store

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When we evaluate a psychological theory, we must take each of the claims it makes in turn, and establish whether they are supported by the evidence we have from studies. Here are some of the claims made by the mutlistore model. For each claim, explain whether the evidence supports of challenges it.

Claim Evidence Supported?

Memory consists of two separate storage areas

Glanzer & Cunitz (1966); Milner (1966)

Information is moved from STM to LTM by rehearsal

Hyde & Jenkins (1973)

STM and LTM are unitary stores that cannot be sub- divided

Baddeley et al (1973); Tulving (1972)

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Working Memory model

Working Memory Baddeley and Hitch (1974)

Baddeley and Hitch questioned the existence of a single STM store. They felt that it was far more complex than just a ‘stopping off’ point for information to be transferred to LTM. They saw STM as a system that actively worked on several pieces of information at once. They weren’t concerned with LTM.

Groome (1999) compared WM to a computer screen, where various operations are being performed on current data.

To replace the single STM store, Baddeley and Hitch proposed a multi component memory system.

Diagram of WM

Components of WM:

Central Executive:

Articulatory control system:

Phonological store:

Visio-spatial scratchpad (or sketchpad):

Research support:

Gathercole and Baddeley (1993): Participants followed a spot of light with a pointer (tracker task). At the same time half the participants had to describe the angles on a letter ‘F’. This group found the task very hard as they were using the visio-spatial scratchpad for both tasks. The other group did a verbal task along with the tracker task and had little difficulty performing both tasks.

Evaluation:

Eyewitness Testimony

Elizabeth Loftus

You may be surprised how difficult it is to remember what a 10p looks like without having one in front of you.

There will be a number of inaccuracies. We do not need to have 100% recall for all

information we use everyday. For example we only need to know the shape of coins and notes to be able to use them correctly.

Schemas:

Knowledge packages built up through experience of the world. They also help us to interpret new experiences.

For example-knowing that there will be tables and chairs in a restaurant. This would be your restaurant schema.

They help to fill in gaps in knowledge we have. However they can lead to distortions when

new information doesn’t fit properly into our existing knowledge.

Cultural experiences and stereotypes affect memory.

These distortions are particularly interesting when we look at EWT.

Research findings on the role of schemas:

Brewer and Treyens (1981) looked at the effects of schemas on visual memory. They asked 30 p’s, one at a time, to wait in a room that had been set up to look like an office for 35 seconds. In the room there were objects such as a desk, chair, calendar and typewriter.

These objects were compatible with an office schema.

However there were a few items that were non-compatible, such as a skull, a pair of pliers and a brick.

In an unexpected recall task the following results were found:

P’s recalled the obvious office items that fitted with schema expectancy, but were less successful at recalling the strange items.

8 p’s, however, recalled the really bizarre item-the skull.

Most errors in recall were substitutions. For example p’s would add in items that weren’t there such as pens, books, and a telephone, which would have a high schema expectancy but weren’t there on this occasion.

Task:

Why do you think that some p’s recalled seeing a skull in the office (Brewer and Treyens, 1981)?

What implications does this finding have for the schema theory?

EWT Stages:

The witness encodes info into LTM (the event and the person involved). May be partial as the event occurs quickly, at night and accompanied by rapid, violent, complex action.

Witness retains info for a time. Memories may be lost or modified during retention, other activities may interfere with the memory itself.

Witness retrieves memory from storage. What happens next is there may be a presence or absence of info that may affect the accuracy of the memory.

Factors affecting EWT:

The main factors affecting accuracy of memory can be placed in to two categories:

Witness factors: age, race, gender and individual response to anxiety or stress.

Event factors: duration of event and level of violence witnessed.

We will be looking at age, anxiety and the effect of misleading information.

Anxiety and EWT:A real crime or violence, usually imparts a feeling of anxiety or stress on the witnesses.

The Yerkes-Dodson law (1908) suggests that up to a point, stress improves performance but after that point, it has a bad effect on performance. Deffenbacher (1983) proposed that the effect of stress on EWT followed that law.

Optimum recall, past this point, recall declines.

Recall

Anxiety levels

Deffenbacher (1983) was one of the first to investigate links between stress and EWT. He found that as we become moderately stressed/anxious, performance in EWT improves. As we hit the peak of stress our levels of accuracy drop because we feel fatigued.

A naturalistic study by Yuille & Cutshall (1986) studies witnesses to a robbery where people had actually been killed or wounded. (What steps would you want them to take if you were the ethics committee?) They found that witnesses were very accurate despite the extreme levels of stress. This has been supported by a study by Christianson & Hubinette (1993) where victims of a bank robbery who had been subjected to the most stress, were actually the most accurate witnesses. Perhaps because their lives depended on it?

Research that supports this idea comes from Peters (1988). Tested people visiting their local health centre. They visited the nurse, for an injection, then spent time with a researcher. A week later they were asked to describe the researcher and the nurse. It was found that they remembered the researcher better than the nurse. This was due to the fact their anxiety levels were heightened at the time they were chatting to the researcher (after injection).

Deffenbacher (2004): reviewed his earlier approach and the claims it was over simplistic. He now believes that as stress increases, so does the accuracy of the memory. When it hits the maximum there is a catastrophic collapse, and accuracy is then severely lacking.

Task: Imagine you are a participant in a study where you saw a bloodstained paper knife or a study where you watch a violent film. Try to imagine how you might feel during and after the investigation. Now, try to answer the following questions:

1. What potential harm might participants suffer as a result of being a participant in either study?

2. How might any risks to participants be reduced?

3. Give some reasons why you think it was ethical or unethical to carry out these studies.

Age of witness:

Age does seem to play a role in how much information we can recall. Dent (1988) found that children perform significantly worse than

adults when recalling details of events and also don’t do as well when asked specific questions.

However, if they are interested in a topic children can recall just as well as adults do. (King and Yuille, 1987).

Children also appear to accept inaccurate information from adults for fear of contradicting adult authority figures.

In a study specific to EWT Ochsner et al (1999) asked children to watch a staged theft. They found more accurate recall compared to children who saw the staged event without the theft. In this case it could be that the children consolidated the memory of the theft by telling others about it, or took the theft more seriously.

Older people also have poor recall of events. Their recall drops below that of young people and middle aged people. They are more likely to make mistakes and are poor at recalling specific details. Elderly men in particular are more prone to distortions through post-event misleading information.

Evaluation:

Research support: Cohen and Faulkner (1989) showed p’s a film of a kidnapping and then presented them with misleading details. It was found that the older p’s (mean age 70) were a lot more likely to than the younger p’s mean age 35) to have been mislead by the suggestive information.

Loftus et al (1991) also found this when p’s

were shown a video tape of a crime the older

p’s were found to be more suggestible than the younger adults who saw the tape.

Conflicting evidence: Coxon and Valentine (1997) found that when comparing the suggestibility of children, young adults and elderly people after watching a videotape of a crime, the elderly p’s were worse at recall. However it was seen that when they were tested for suggestibility they were no worse than the young adults. In fact they were seen to be less suggestible.

Other conflicting evidence: It is still unclear why these age effects occur. It could be that the younger p’s have been more used to memory tests recently. Or it could be that the older p’s poorer health may be a factor in decline in memory. In fact it may be this that is the important factor, not age.

Loftus

Factors affecting eyewitness testimony:

• Elizabeth Loftus is a psychologist who argues that eyewitness testimony in court is very unreliable.

• She looked at whether people reconstruct memory, whether the memory persists (stays) or whether they can be ‘led’ in to answering in a certain way.

Leading Questions:

• Loftus and Palmer (1974): investigated how information given after an event affects a witness’s memory for that event.

• 45 participants took part. They all saw a video of a traffic accident.

• After the video they were all asked the same questions about the accident.

• Apart from 1 question which was about the speed the cars were going.

• 9 participants had the cars ‘smashing’• The other group had the verbs ‘hit’, ‘bumped’,

‘collided’, ‘contacted’.

• Results: Group with ‘smashing’ estimated the highest speed of the cars.

• The participants were not very good at estimating how fast the cars were actually travelling.

• Speed estimates depended on the verb used.

Table of results:

Verb Mean Speed EstimatesSmashed Collided

BumpedHitContacted

Conclusion:

• We can conclude that people’s memory for an event can be influenced by the questions they are asked about it and those questions can distort (change) our long term memory for an event.

• We don’t know whether the reported speed was due to a genuine change in the participant’s memory, or through demand characteristics (participants guessing the true nature of the experiment). (Gross, 2003).

Evaluation:• A similar follow up study was done where

participants were given a question about whether they had seen broken glass on the road (there was none). 14% of participants with ‘hit’ reported seeing glass. Whereas 32% of the participants with the word ‘smashed’ reported seeing glass. There seems to be evidence that suggests post event misleading questions can have an adverse effect on EWT.

Eyewitness Testimony task:

1. What are the 3 stages that eyewitness testimony goes through?

2. What was the general assumption about EWT before the Devlin report?

3. In your own words write down the APFCC of Loftus & Palmer (1974).

4. Which factors effect EWT?

5. What does research suggest about the reliability of EWT?

6. Do leading questions effect EWT?

7. Do people believe EWT?

Which of these items are true and which are false?

Loftus & Palmer (1974)1 used a repeated measures design with 45 students

T or F

2 short film clips of traffic accidents were shown T or F3 L & P found that the speed estimates from pps varied with the verb used in the question

T or F

4 the population validity of this study was questionable as they only used students

T or F

5 the mundane reality of this study was good as pps were less anxious than if seeing a real accident

T or F

6 subsequent studies offered a monetary reward for the correct answer, eliminating design effects

T or F

7 the conclusion of this study was that misleading information alters memory recall

T or F

Read the following passage at normal reading speed once. Then turn the page over and write down as many points from the passage as you can remember.

Look at the following picture. Then turn the page over and write down/draw as many points from the picture as you can remember

ACTIVITY: Out of context

STUDY THIS PICTURE

STUDY THIS PICTURE

The Cognitive Interview: CI

What is the cognitive interview?

• So far we have gone over what the problems are with eye witness testimony.

• Here however we will look at the cognitive interview a technique used by the police in order to gain more accurate information.

Fisher and Geiselman (1992):• They believed that one way in which we

remember events more accurately is to put them in to context.

• They also said that we can remember more if we are given retrieval cues.

Four components of the original cognitive interview:

1. Report everything: the interviewer encourages the reporting of every single detail of the event, even though it may seem irrelevant.

2. Mental reinstatement of original context: the interviewer encourages the interviewee to mentally recreate the environment and contacts from the original incident.

3. Changing the order: the interviewer may try alternative ways through the timeline of the

incident by reversing the order in which events occurred.

4. Changing the perspective: the interviewee is asked to recall the incident from multiple perspectives, for example by imagining how it would have appeared to other witnesses present at the time.

• The assumption of the first 2 components is to see if there is a consistency between the actual incident and the recreated incident.

• The other 2 components are there to see if the information observed can be retrieved from memory via other ‘routes’.

Research into the cognitive interview:• A meta-analysis (collection of data from lots of

different studies) of 53 studies found, on average, an increase in the amount of correct information generated in the CI compared with standard interviewing techniques (Kohnken et al.,1999).

• However most of these studies were tested in the lab and witnesses were usually college students.

• Milne and Bull (2002) examined the relative effectiveness of each component.

• Undergraduate s and children were interviewed using one component and compared to a control group (who were instructed simply to ‘try again’).

• Recall across all components was similar and not much different than the control group.

• However when the components were used together the recall was much higher.

Evaluation:• The problem with evaluating the CI is that it no

longer has one procedure. It is a collection of related techniques.

• Thames Valley Police use the basic Fisher and Geiselman technique without the ‘changing perspectives’ component.

• Other police forces who say they use the technique only use the ‘reinstate context’ and ‘report everything’ components (Kebbell and Wagstaff, 1996).

• An enhanced version of the technique by Fisher and Geiselman (1992) requires more training and requires more strain on the interviewer.

• Memon et al. (1994) showed that experienced detectives received only a brief (4 hours) training in the use of CI, which did not produce any significant increases in in the amount of information gained from the witnesses about

an incident (when compared with standard techniques).

Improving Memory:

Strategies for memory improvement: Organisation

Demonstrations show that organised material is easier to recall than disorganised material.

Evidence suggests that when given random material, we try to organise it.

Demonstrations that instructions to organise material enhance participants recall.

There are many studies which show the importance of organisation for memory improvement.

Many of these involve mnemonics, which are strategies for memory improvement.

Simply using a list to remember your shopping would count as a simple yet effective mnemonic device.

Categories task:

In a moment you will be shown 2 lists of words for 20 seconds

You will be shown each list one at a time. After the first list is shown to you I want you to

write down as many of the words as you can. I will then show you the other list and then you

will do the same task, writing down as many words as you remember.

Chunking:

Our STM capacity can be improved if separate ‘bits’ of info are grouped in to larger ‘chunks’.

For example 19391945 can be chunked in way that it will be seen as the start and end date of the Second World War.

When we read we ‘chunk’ letters in to words and words in to sentences.

Miller preferred to view STM as 7+/-2 chunks of information rather than individual pieces of information.

Imagery:

Imagery is seen to be the most important mnemonic (Rolls, 2007).

The method of loci is used here. This is the oldest documented mnemonic. Loci means locations It basically refers to the individual making

mental representations of familiar routes i.e. your walk to college.

You then use images to represent the words or items you are trying to remember.

Then you visualise the route and place the images at ‘loci’ along the route.

The more bizarre the image the better. To recall the list you recreate the route in your

head, noticing the various items from the list along the way, until you have remembered the entire list.

Evaluation of Imagery:

An advantage of this method is that you recall information in the correct sequence.

However you cannot re-use the route too often because you might cause interference with other information you might be using.

It is difficult to remember a certain item because you have to go through the entire list.

Peg word mnemonic:

The word mnemonic just means a way to improve memory.

The mnemonic below uses visual imagery and rhyme and rhythm, it also uses numbers instead of places. The numbers are transformed in to images by using a simple rhyme.

One is a bun

Two is a shoe Three is a tree Four is a door Five is a hive.

For this to work well you have to imagine the number interacting with the item you have rhymed the number with.

Evaluation: You have to learn the rhyme by rote

(repetition) so there is more to remember here.

One major problem is that when there is more than one list to be recalled then there can be interference between the lists.

This makes it a slow process. Coupled with the fact you have to repeat the rhyme each time.

It also doesn’t work well with abstract words like ‘hope’. You also need to practice the technique extensively.

‘Non-memory’ factors that improve memory Hermann and Palmisano (1992) state that a

person’s environment or their emotional state can have an effect on the ability to remember information.

Context remembering/forgetting links in with the ideas mentioned above. A study by Godden and Baddeley (1975) got underwater divers to learn lists of words either on dry land or underwater. If they were asked to recall the words in the same place they were learnt, i.e. underwater, they recalled more words than if they were in a different place for example on dry land.

State-dependent remembering/forgetting:

This looks at a person’s emotional state and also the physical state they are in. For example Goodwin et al (1969) looked at alcohol. They found that when a participant was drunk and hid money they were more likely to find the hiding place when they were in their original drunken state.

ASSESSMENT:1. Define what is meant by the terms ‘encoding’, ‘capacity’ and ‘duration’. (2 + 2 + 2 marks)

2. Distinguish ONE difference between STM and LTM as suggested by the MSM. (3 marks)

3. Describe the multi-store model of memory. (6 marks)

4. Explain one strength of the MSM. (2 marks)

_____________________________________________________________________________________________________________________________________________

5. Outline TWO weaknesses of the MSM. (2 + 2 marks)

6. Using the MSM, outline the processes involved in storing and retrieving material in LTM. (4 marks)

7. Explain how evidence from brain damage patients has helped to support the multi-store model. (6 marks)

_______________________________________________

_______________________________________________

8. ‘Peter was trying to remember the name of his first teacher at primary school without success. Then his mother managed to find an old class photo, which she showed Peter. The name of his teacher then popped into his mind.’ Explain why Peter was suddenly able to remember. (6 marks)

9. Outline and evaluate the MSM. (12 marks)

______________________________________________

10 Explain your answer.

Model answer: 12 mark essay question.

OUTLINE AND EVALUATE THE MULTI-STORE MODEL OF MEMORY (12 MARKS)

The multi-store model (MSM) of memory was proposed by Atkinson and Shiffrin (68). It suggests that our memory is divided into 3 memory stores: Sensory memory, Short term memory (STM) and Long term memory (LTM). Information flows firstly through the sensory memory to STM using attention, it can then be transferred to LTM using elaborative rehearsal but goes back to STM using retrieval.The sensory memory is a store which processes information for a very short moment in time (Sperling ’60) based upon our 5 senses which decays quickly.The capacity of STM is 7 +/- 2 according to Miller (56) who discovered this using a digit span technique. The duration of STM is 18 seconds according to Peterson and Peterson (59) who developed the Brown-Peterson technique which uses trigrams and interference tasks to assess memory, however, according to Atkinson and Shiffrin (68) the duration is 30 seconds because it can be extended to this length with rehearsal. In terms of encoding it is acoustic according to Baddeley (66) following an experiment using confusing words which either sounded similar or had the same meaning.According to Solso (91) the capacity of our LTM is potentially enormous even in comparison to a computer. The duration of LTM is according to Bahrick et al (75) a minimum of 34 years however it probably a great deal longer from his study into High School Yearbook photos. The encoding of LTM is believed to be semantic according to Tulving (89).One strength of this model is the amount of supporting research, for example Murdock suggested that the MSM could account for the primacy and recency effects seen by Glanzer and Cunitz (66), and thus suggests that the model is reliable.However, in criticism, the experiments used to suggest capacity, duration and encoding limits lack ecological validity because they were conducted in laboratories which are artificial settings and may produce demand characteristics in the participants.An additional criticism is that the model is to simplistic, according to Shallice and Warrington (70) who conducted an investigation into KF. He was a patient who suffered from brain damage meaning he was unable to process verbal information in the STM but could process visual information thus suggesting STM is not a single store. This idea is supported by Baddeley and Hitch (74) with their working memory model.An additional strength of the MSM is provided by Scoville and Milner (57), they suggested that the hippocampus is the gateway to the LTM store from their study of an epileptic patient called HM. HM’s hippocampus was removed in order to ease his epilepsy resulting in him being unable to form new long term memories, though he could access old long term memories he had already made. Therefore, suggesting that memory is comprised of more than one store and thus the MSM is an accurate description of memory. In conclusion, there are numerous strengths and weaknesses of the MSM however, more up to date research needs to be conducted in order to fully assess it’s reliability and validity given changes in technology.

Model answers

Memory Question

Booklet

1) Explain how the duration of STM has been investigated (5)Peterson and Peterson (1959) investigated the duration of STM in a lab experiment using the Brown-Peterson technique. They showed ps trigrams (eg BLM) one at a time and then asked them to count backwards in 3s from a given number. This was done in order to prevent rehearsal of the trigrams, which would have biased the experiment. The time delay between presentation and recall of the trigrams was varied between 3 and 18 seconds. Ps were then asked to recall the trigram. The trigrams contained no vowels so as to avoid the influence of LTM.

Other psychologists have investigated the duration of STM in a similar way but have used only a small number of trigrams in order to prevent confusion.

2) Explain how studies of STM have been controlled (4) Peterson and Peterson controlled their study into short term memory by ensuring there were no vowels in the trigrams, meaning that ps could not make words from them. They also prevented ps from rehearsing using an interference task. In studies using word lists, the researcher ensures that the words in each list are of equal difficulty and length etc.

Researchers control the rate of presentation of their stimuli, ensuring that all words/digits are presented at the same speed.

3) Explain what research into STM has shown (6)

STM research has shown that STM has a short duration. Peterson and Peterson (1959) found that ps forgot trigrams very rapidly when they could not rehearse them. After 18 seconds, only 10% of trigrams were recalled. Miller showed that the capacity of STM is 7+/-2, meaning that most people can hold about 7 groups of meaningful information in their memories at once – some a few more, others a few less.Baddeley found that in an STM task, ps confused words that sounded alike but could remember the same number of words that did not sound alike. This shows that STM encodes acoustically.

(Shulman found that STM can encode semantically)

4a) Sally is a telephone executive. She can recall landline numbers while she dials but if she calls a mobile she cannot remember the number. Explain why this may be. (3)This may be because the capacity of STM is very small – around 5-9 digits. A landline number is shorter than a mobile phone number

and so is more likely to be remembered. Sally can clearly not fit the 9 digits of a mobile number into STM.

OR – Perhaps Sally can remember a landline number because she forms a chunk with the area code, which she already knows. Then she only has to recall 1 chunk + 6 digits – this is within the capacity of STM.

4b) Sally has noticed that even though she remembers landline numbers while she dials, by the end of the call, she has forgotten them. Explain why this may be. (3)

It is likely that Sally has forgotten the numbers by the end of the call because of the short duration of her STM. Research has shown that STM duration is only 18 seconds if there is no rehearsal. When she is talking on the phone she cannot rehearse and so the number is forgotten.

Explain how the duration of LTM has been researched by psychologists (6)

Shepard researched the duration of LTM by showing ps pictures and recording how many they could recall 4 months later. In a lab experiment, Bahrick et al researched LTM using a high school year book. He took ps aged 17-74 and asked them to free-recall their class mates from high school (ie recall their names off the top of their head). Next, he tested recognition memory by asking them to recognise names of classmates from a list of names and to recognise pictures of classmates. He recorded the number of classmates recalled and compared it to the age of the participant in order to determine the duration of the memory.