Cognitive Psychology

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2.1 CONTENT

2.1.1 THE WORKING MEMORY MODEL

Baddeley and Hitch, 1974

The working memory is a temporary storage system under attentional control that underpins our capacity for complex thought

The central executive:

Manages the two slave systems

Retrieves information the 5 senses or from LTM and assigns it to the Loop or the VSSP for processing

An attentional controller with the capacity to focus, divide and switch attention

The Visuo-spatial sketchpad:

One of the salve systems

The role is to maintain and integrate casual and spatial information from these different channels using a visual code

The phonological loop:

One of the slave systems

Deals with temporary storage of verbal information

Phonological store: Linked to speech perception. Holds information in a speech-based form (i.e. spoken words) for 1-2 seconds

Articulatory process: – Linked to speech production. Used to rehearse and store verbal information from the phonological store

Improvements to the working memory (2000,2007)

In 2000, Baddeley published a new version of Working Memory with a new, third slave system: the Episodic Buffer.

This system works between the Loop and the VSSP and specialises in episodic LTM, bringing elements of information together into patterns or stories.

Episodic buffer: a temporary storage system that is able to combine information from

the loop, the sketchpad, long-term memory, or indeed from perceptual

input, into a coherent episode

Evaluation of the working memory model

Neurophysiological evidence:

Case study of KF who suffered short-term memory impairment following a motorbike accident that damaged his parietal lobe of his brain

KF had a digit span of 1, suggesting a large impairment in his phonological store, but his visual memory was intact

Experimental evidence:

Its credible because it's supported by the dual task paradigm

Baddeley (2003) tested participants’ recall of similar sounding letters (E, G, P, etc) and found they got lower scores than with dissimilar letters (W, X, K, etc). If the Phonological Loop is overloaded, that would explain this

Application:

Dementia patients

By giving them a quiet environment, so that background noise doesn’t confuse them with dual tasking

Conclusion:

Working Memory is the most successful memory model at the moment. It has been changed and improved over the years but it still fits in with what we know about the brain. However, more research needs to be done on the Episodic Buffer which is rather unclear.

2.1.2 THE MULTI-STORE MODEL OF MEMORY

ATKINSON AND SHIFFRIN 1968

Describes how information flows through the memory system

Its only a model so not real representation

The multi-store model of memory describes memory as consisting of three basic stores: a sensory register, short-term store and long-term store

The process:

Memory is viewed as information which comes from our environment through the 5 senses. It is stored (briefly) in Sensory Memory, which lasts less than a second. If information is attended to, it flows into STM, which has a duration of up to 20 seconds. If it is rehearsed, it is encoded in LTM which has an unlimited duration.

Information can be retrieved from LTM and brought back into STM. Information can be recalled from STM and brought into the conscious mind

Evaluation of the multi-store model of memory

Studies of patients with brain damage:

HM suffered amnesia following brain sure for epilepsy, resulting in severe impairment to his long term memory but his short term memory was largely intact

This demonstrates that the short-term and long-term memory stories were differently affected by the brain damaged causes, perhaps because they are located in different regions of the brain

HOWEVER there are objections based on cases like Shallice & Warrington (1970). They report that K.F. who lost STM in a crash, could still make new LTM memories. MSM can’t explain this.

Serial position effect:

This states that recall of information at the beginning and end of a list is higher than the middle of the list

Glanzer and Cunitz (1966) conducted an experiment to investigate whether the position of a word in a list affected recall; they found participants recalled more from the beginning and end go a word list.

This is due to words at the beginning of the list had chance to be rehearsed and therefore transferred to the long term store. The words at the end where in the short term store

2.1.3 EXPLANATION OF LONG-TERM MEMORY: EPISODIC AND SEMANTIC MEMORY

TULVING 1972

Proposed that the long-term, more could be divided into two memory stores: episodic memory (remembered experiences) and semantic memory (remembered facts)

The difference between semantic and episodic memory

Nature of memory:

Semantic: mental encyclopaedia

Episodic: mental diary

The referencing:

Semantic: independent of time referencing, input can be fragmentary

Episodic: time and context referenced, input is continuous

Retrieval and forgetting:

Semantic: retrieval possible without learning, not cued retrieval

Episodic: retrieval using cues which are encoded at the point of learning

Forgetting:

Semantic: memory trace more robust and less susceptible to transformation

Episodic: forgetting due to retrieval cue failure, memory trace can be changed/ transformed

Evaluation Tulving's theory of long-term memory

Supported by lab experiments:

Baddeley (1966b); Baddeley showed that LTM is confused by word lists with similar meanings. LTM must be encoded semantically because similar sounding word lists had no such effect.

HOWEVER, studies lack ecological validity because they are unrealistic. Learning lists of similar sounding words is not an ordinary activity. This means the theory is based on research that lacks validity.

Application:

It has real-world applications

You could help dementia patients by giving activities like singing songs that are semantically meaningful for them then asking them about their feelings

This is Cognitive Stimulation Therapy.

2.1.4 RECONSTRUCTIVE MEMORY (BARTLETT, 1932)

Bartlett’s central insight was that memory is not like a tape recorder: it doesn’t faithfully play back our experiences. Instead, it changes or “reconstructs” them imaginatively

Schemas

Schemas are parcels of stored knowledge or a mental representation of information about a specific event or object

We draw on our schema when we recall an event to fill in the gaps

'The war of the ghosts'

Bartlett showed 20 students a Native American ghost story ('the war of the ghosts') which had unusual features. He asked them to read it then recall it on several occasions after a few hours, days, weeks or even years. Bartlett compared how the recalled versions of the story differed from the original.

Participants confabulated details, changing unfamiliar parts of the story to familiar ideas in line with their schemas.

E.g. canoes and paddles became boats and oars, hunting seals became fishing

Evaluation

A weakness with the original studies into Reconstructive Memory is that they were not very scientific. For example, Bartlett showed how participants changed The War of the Ghosts to fit in with their own expectations and understanding, such as replacing canoes with boats. Bartlett tested his Cambridge students during tutorials and carried out one test in the street, two years later.

However, in the ‘70s, Loftus did research into schemas with standardised procedures and experimental controls. She found schemas about car crashes made some participants falsely remember broken glass. Loftus followed standardised procedures that are easily replicated.

You could apply the idea of schemas to helping dementia patients by going along with beliefs or activities that are meaningful for them. This is Validation Therapy and it is used at the “dementia village” in Hogeway where residents live in houses that fit in with their schemas.

Reconstructive memory is similar to Tulving’s idea of semantic LTM. Schemas seem to be semantic stores and Tulving suggests that semantic memory can cause episodic memories to change, which is exactly what schemas do. The two theories are more valid since they support each other.

In conclusion, reconstructive memory is a very important idea because it suggests that eyewitnesses may not be reliable. However, it is controversial because a lot of the studies into it are either unscientific or extremely artificial or both. In real life, our memories may be more reliable than this theory makes out.

2.1.5 INDIVIDUAL DIFFERENCES IN MEMORY

Cultural

Mary Mullen (1994) carried out the first cross-cultural research into memory

Asked more than 700 Caucasian and Asian students to describe their earliest autobiographical memories (memories of things that happened to them).

Asian students' first memories happened six months later than the Caucasian students' first memories

Development differences

Memory improves with age, peaking in middle life and declining with old age

Personality

There is some evidence that introverts have better long term memory (LTM) because they experience more cortical arousal when stressed but extroverts have lower cortical arousal and better short term memory (Cox-Fuenzalisa et al., 2006).

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2.2 METHODS

2.2.1 EXPERIMENTS

Lab experiments

An experiment conducted in a controlled environment

Strength:

Can control for extraneous variables

Internal validity as the researcher can be sure the IV affected the DV as they have full control over all variables

Weakness:

Lacks ecological validity; artificial setting

Obvious to participants that they are in an experiment which could reveal demand characteristics

Field experiments

Research that takes place in the setting where the behaviour being studies would occur naturally

Strength:

High ecological validity as takes place in a real life setting

Reduces demand characteristics as participants are likely to be unaware they are in an experiment

Weakness:

Lack control over extraneous variables

Hard to be confident on cause and affect conclusions

Comparing Lab and Field experiments

2.2.2, 2.2.8 VARIABLES

Independent variable: the variable the researcher manipulates

Dependent variable: the variable the researcher measures

Extraneous variable: a variable that may have affected the DV but that was not the IV

Confounding variable: a variable that affects the findings of a study directly, so much that you are no longer measuring what was intended

Situational variables

An extranous variable that might affect the results of the study found in the environment in which the study is conducted

lighting

time of day

temperature

Participant variables

Participants themselves affect the results of the study

Age

Intelligence

Type of personality

2.2.3, 2.2.4 HYPOTHESIS

A hypothesis is a precise, testable statement of what the researchers predict will be the outcome of the study.

Null hypothesis

States that there is no relationship between the two variables being studied (one variable does not affect the other)

It states results are due to chance

One-tailed directional hypothesis

Predicts the nature of the effect of the independent variable on the dependent variable.

E.g. Adults will correctly recall more words than children

Two-tailed non-directional hypothesis

Predicts that the independent variable will have an effect on the dependent variable, but the direction of the effect is not specified.

There will be a difference in how many numbers are correctly recalled by children and adults.

Experimental hypothesis (same as alternate)

States that there is a relationship between the two variables being studied (one variable has an effect on the other)

It states that the results are not due to chance

2.2.5 RESEARCH DESIGNS

Independent groups design

When participants are divided into groups ad are only involved in one of the experimental conditions of the experiment

Strength:

Ppts are less likely to guess the aim of the investigation as they only take part in one condition. Reduces demand characteristics

Weakness:

You need more participants for the experiment

Repeated measures design

This is when all participants take part in all conditions of the experiment

Strength:

Fewer participants are needed

Weakness:

Demand characteristics chance increases as ppts have knowledge of all conditions so can moe easily guess the aim

Matched pairs design

When different participant are assigned to each condition of the experiment but they are matched on characteristics important to the study

Strength:

Reduces participant variables because the researcher has tried to pair up the participants so that each condition has people with similar abilities and characteristics

Weakness:

Very time-consuming trying to find closely matched pairs

Impossible to match people exactly unless identical twins

2.2.7 ORDER EFFECTS

When the performance of participants in one condition is influenced by the previous conditions the experiment

e.g. fatigue - they may under perform in second task if they are tired

e.g. practice - they may perform better in second condition

2.2.9 OBJECTIVITY, RELIABILITY AND VALIDITY

Reliability

Refers to the consistency of finds from research

Validity

Refer to whether the study is measure the behaviour or construct intends to measure

Internal validity: the extent to which the outcome of the study is the direct result of the manipulated IV

External validity: the extent to which the findings apply to other people and situations

Construct validity: the extent to which the test measures what it claims to measure

Ecological validity: the extent to which the findings still explain the behaviours in different situations

Population validity: the extent to which the findings can be applied to other people

Objectivity

Referes to the need to be impartial and judgemental free

2.2.16 CASE STUDY OF HM

About

Henry suffered from epilepsy caused by a head injury when he was seven. As he grew up, his seizures got worse, until surgery was his only hope for relief

The pioneering brain surgeon William Beecher Scoville proposed to remove the part of the brain that was causing the seizures.

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2.3 STUDIES

2.3.1 CLASSIC STUDY

BADDELEY (1966b)

Aim

To find out if LTM encodes acoustically (based on sound) or semantically (based on meaning)

Sample

72 en and women from the Cambridge University subject panel; they were volunteers

There were 15-20 in each condition; there were 4 conditions

Procedure

Participants were split into four groups

Each group views a slideshow of a set of 10 words. Each word appears for 3 second

Acoustically similar condition:

Participants get a list of words that share a similar sound (man, cab, can, max, etc)

The control group get words that are all simple one syllable words but they do not sound the same (pit, few, cow, pen, etc)

Semantically similar condition:

Participants get words that share a similar meaning (great, large, big, huge, etc)

Control group get words that are unconnected (good, huge, hot, safe, etc)

Participants in all 4 conditions then carry out an “interference test”

Then they recall the words from the slideshow in order

This is repeated 4 times

Results

Acoustically similar words seem to be confusing at first, but participants soon “catch up” with the Control group and even overtake them, but this isn’t statistically significant

Semantically similar words do seem to be confusing and the experimental group lags behind the Control group

Conclusion

Baddeley concludes that LTM encodes semantically, at least primarily. His earlier experiments suggest STM encodes acoustically.

This is why LTM gets confused when it has to retrieve the order words which are semantically similar: it gets distracted by the semantic similarities and muddles them up

Evaluation

Generalisability -

A volunteer sample might have more people with particularly good memories who enjoy doing memory tests - not representative of people in general

Reliability -

It has standardised procedures that you could replicate yourself

Application -

For your own revision; if LTM encodes semantically, it makes sense to revise using mind maps that use semantic links

Validity -

Lacks ecological validity as the task is artificial, however sometimes you have to do it e.g. shopping lists

Ethics -

No significant ethical issues

2.3.2 CONTEMPORARY STUDY

SCHMOLCK ET AL (2002)

Aim

To find out if Semantic LTM is linked to a particular part of the brain

Sample

6 patients with severe damage to the MTL and 8 Controls with no brain damage

Matched pairs design as controls were matched on age and education

Procedure

Dr Schmolck created 9 tests for Semantic LTM functions

E.g. Category sorting: the participants were given all 48 pictures and asked to sort them into “living” or “man made”

All were based on a set of 48 drawings, half of animals and half of objects

These pictures were grouped in sixes: 6 land animals, 6 birds, 6 musical instruments, 6 vehicles, etc

The participants were tape recorded and their responses transcribed (typed up). 14 'raters' checked each transcript

Results

The MTL+ group were significantly worse in all the tests

Positive correlation between the amount of brain damage and the number of mistakes

Conclusion

Seems to be a clear link between damage to the temporal cortex generally and the loss of semantic LTM. Patients with damage specific to the hippocampus suffered loss of episodic memory, but not semantic memory

suggests that semantic and episodic LTM are encoded in different parts of the brain

Evaluation

Generalisability -

Small sample

Reliability -

Standardised procedure that can be replicated, also high inter-rate reliability

Application -

For cognitive psychologists who have built upon the findings to understand more about the brains role in memory

Validity -

Lacks ecological validity as the task is artificial and doesn't represent the memory we need in real life

Ethics -

The brain damaged patients may not have reenable to give valid consent, which makes it unethical. But the findings have benefited scientific research enormously and so the benefits might outweigh the ethic issues

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2.4 KEY QUESTION

2.4.1, 2.4.2 ONE KEY QUESTION OF RELEVANCE TO TODAYS SOCIETY

HOW CAN KNOWLEDGE OF THE WORKING MEMORY BE USED TO INFORM TREATMENT OF DYSLEXIA?

Dyslexia is a general term for disorders that involve difficultly in learning to read or interpreting words, letters or symbols but it does not affect general intelligence. We know this due to the fact that two of the most famous dyslexics were Albert Einstein and Leonardo da Vinci, who are extremely intelligent and have achieved great things. Dyslexia is an extremely common problem in all ages of people, 1/10 of the population are to have dyslexia and more than 6.3 million people in the UK. Research found that illiterate pupils by the age of 37 cost taxpayers around an additional £50000 a year when you add extra costs relating to education systems, unemployment and criminal justice systems. Therefore, these issues mean that dyslexia is a problem that’s relevant in today’s society and if it was to be more understood, external costs and better treatment could be an outcome

The working memory model (Baddeley and Hitch 1974) seems to relate to dyslexia in many different ways. Firstly, dual task experiments require participants to perform two tasks simultaneously that involve one or more slave system of working memory, in other words they are experiments, which show that there is a problem with using the same component for two tasks, which is part of working memory.

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2.5 PRACTICAL INVESTIGATION

2.5.1 ONE PRACTICAL RESEARCH EXERCISE

intro

Directional hypothesis: Participants would recall more acoustically similar words in their long-term memory after ten minuets than participants who are given semantically similar words

Null Hypothesis: There will be no difference in the number of acoustically or semantically similar words recalled from the long-term memory

Design: Independent groups design as we only used on group of participants and this increased external validity and reduced demand characteristics

Method: We used opportunity sampling; 4 adults (2 male, 2 female) and 8 SGA students ranging from year 10-12.

procedure

Four lists containing 10 words were presented on a laptop powerpoint with one word changing event three seconds in the correct order in which they were meant to be recalled

After the first list of words was presented the participants were required to do a distraction task, which involved a 6-digit sequence which they had to recall back 6 times

Participants repeated this 3 ore times

After the last distraction participants had to recall the word list in the correct order

discussion

Recall of the acoustical similar sounding words was worse than the dissimilar sounding words during the initial phase of learning. Although, recall of the dissimilar and similar sounds words was not statistically significant.

The fact that participants found it more challenging to recall list one in the initial phase of learning suggests short-term memory is largely acoustic and therefore, acoustically similar sounds words are difficult to encode.