Research Methods- Brain Scans, Twin & Adoption Studies, Correlations

Question 1

What does PET scan stand for?

Answer 1

Post emission tomography

Question 2

How do PET scans work?

Answer 2

• patients having a PET brain scan are injected with FDG = a tracer substance where the radioactive atom is attached to glucose because the brain will use it up as a form of energy.
• once the tracer has been absorbed into the blood stream, a task will be given to stimulate the brain and encourage activity
• as the brain works glucose it used up and radioactive atoms start to break down, emitting positrons and gamma rays are produced

Question 3

How do PET scans form an image?

Answer 3

A computer analyses the gamma rays and produces an image of the brain in colour, with high levels of activity shown in warmer colours e.g red, and low levels shown by cooler colours e.g blue.

Question 4

How do psychologists use PET scans in research?

Answer 4

• used to investigate areas of the brain that aren’t functioning normally
• can detect areas of damage by indicating which parts of the brain are showing abnormal levels of activity, helping to see where problems exist and predict any issues patients may find in relation to brain activity being shown

Question 5

Explain 3 strengths of using PET scans.

Answer 5

• High validity= data collected is objective, so there is no chance of experimenter bias, therefore is highly accurate
• High reliability= due to the standardised procedure of the brain scan, it can easily be repeated, therefore results can be compared and analysed for consistency
• Helps in early interventions= PET scans are able to predict what kind of issues patients might face in relation to the brain activity

Question 6

Explain 3 weaknesses of using PET scans.

Answer 6

• More invasive then other techniques= require the patient to be injected with a radioactive substance and is unclear whether there are any long term effects of this method, therefore can’t have this scan too often
• PET scans can’t pinpoint exact locations of brain activity, just shows the general area, which isn’t as informative

Question 7

Give a piece of research to support the use of PET brain scans

Answer 7

Raine et al (1997)
-used PET scans to investigate differences between the brains of murderers and non-murderers. They were able to map abnormal brain activity in the murderer’s group in areas of the brain associated with impulsivity and risk-taking behaviour, which may explain increased aggression.

Question 8

What do FMRI scans stand for?

Answer 8

Magnetic resonance imaging

Question 9

How do MRI scans work?

Answer 9

• your head is placed inside a very large and powerful electromagnet
• inside the magnetic field, the nuclei within the hydrogen molecules in water align themselves with the direction magnetic field.
• As neural activity increases in the brain, blood flow increases in the active areas to keep up with oxygen demand. Oxygen is carried to neurons in haemoglobin within red blood cells, which when carrying oxygen, repels a magnetic field.

Question 10

How do MRI scans produce an image?

Answer 10

-it is the changes in the direction of the magnetic field that the scanner detects to form an image. The scanner sends the information to a computer that us able to create a map of activation to show changing levels of neural activity in different brain areas as tasks are being completed.

Question 11

How do psychologists use MRI scans?

Answer 11

• provide insights into brain development
• used in pediatric psychology research to localise cognitive functioning and examine differences in brain structures and processes

Question 12

Explain 3 strengths of using MRI scans

Answer 12

• Is able to map precise detail and areas of the brain, providing more information
• highly reliable= use of standardised procedures
• preffered method of choice for psychologist to use= classed as the safest and is a non invasive technique

Question 13

Explain 3 weaknesses of MRI scans.

Answer 13

• practicality= requires patients heads to remain extremely still as any slight movement can result in distorted images
• not suitable for everyone due to the use of the high powered electric field= anyone with a pacemaker, metal surgical implants etc can’t have one of these scans
• very expensive= due to the extremely scientific machinery and process, it is expensive to run

Question 14

Give a piece of supportive research for MRI scans.

Answer 14

Lie to al

Question 15

What do CAT scans stand for?

Answer 15

Computer axial tomography

Question 16

How do CAT scans work?

Answer 16

-CAT scans of the brain consist of passing X rays into the head, but multiple beams are passed around the head from at different angles at once to gather more information

Question 17

How do CAT scans produce an image?

Answer 17

-the information from the multiple X-ray beams is interpreted by a computer and a detailed image of the structure of the brain can be seen

Question 18

How are CAT scans used by psychologists?

Answer 18

-useful for detecting areas of brain damage following an accident or positioning of brain tumours

Question 19

Explain 2 strengths of using CAT scans

Answer 19

• very quick to conduct= useful when needing to make a quick decision in medical procedures
• objective and scientific method= produces a series of images which provide accurate detail of brain structure

Question 20

Explain 3 weaknesses of using CAT scans

Answer 20

• practicality= patients need to remain as still as possible as slight movement will distort the image
• limited use= due to exposure to radiation it is advised they’re only used when the possible benefits in relation to a diagnosis outweighs the potential risks
• only investigate brain structure= not as informative as other brain scans therefore

Question 21

Give a piece of research to support the use of CAT scans

Answer 21

Bette (2009)
-the case of Herbert Weinstein, whose defence used CAT scanning to show some damage, and this evidence was used to persuade the jury that his actions were not thought through; he did not know sufficiently right from wrong

Question 22

What is a genotype?

Answer 22

An individuals collection of genes that is made up of chromosomes and fixed at conception

Question 23

What is a phenotype?

Answer 23

An individuals observable traits which can be influenced by environmental factors e.g IQ

Question 24

What are the two types of twins? How much DNA do they share with each other?

Answer 24

Monozygotic= identical =100%
Dyzogotic= fraternal= 50%

Question 25

What is meant by a concordance rate?

Answer 25

The rate of agreement between 2 variables. It tells us the percentage of cases where the behaviour occurs in both twins, rather then just one. If behaviour is genetic, we’d expect concordance rate to be higher amongst MZ twins because they are most genetically alike.

Question 26

Describe a twin study as a research method (4)

Answer 26

1. MZ twins share 100% of their genes and DZ twins share only 50%, therefore studying the behaviour of twins reveals a lot about the influence of nature
2. If MZ and DZ twins behave differently, it suggests nature is at work, because the shared environment is not producing the same behaviour, so different genetics explain this
3. Twin studies are measured using a statistic called a concordance rate. Concordance means rate of agreement. If one twin shows a behaviour and the other twin does too, this is concordance
4. Concordance rate is usually expressed as a percentage (100% concordance means all the twins shared the behaviour in common, 0% means none of them did). In a twin study, the concordance rate of the MZ twins is compared to the concordance rate of DZ twins

Question 27

Explain some strengths of using twin studies.

Answer 27

1) MZ twins share 100% of their DNA which is useful as no other humans share 100% of their DNA, therefore no other way to study genetic influences so clearly
2) Reliable due to large volume of data produced for secondary data…

Question 28

Explain some weaknesses of using twin studies.

Answer 28

1) concordance rates are never 100% when comparing MZ twins therefore it’s difficult to draw a trustworthy cause and effect relationship between genes causing behaviour alone
2) Low internal validity as its hard to separate genes and the environment when studying MZ twins because twins are brought up in the the same environment and treated the same, therefore concordance rate may be due to environmental factors as well as genetics
3) Low generalisability as MZ twins are more likely to be treated the same then DZ twins, and different roles in the family and gender of twins may influence behaviour, therefore can’t generalise all twin findings to all twin pairs let alone rest of population

Question 29

Give a strength and a weakness of using separated MZ twins in research

Answer 29

Strength- deals with environmental issues because if the twins are separated into 2 different environments, their behaviour can be shown to be as a result of genetics, if remain similar, or the environment, if behaviour is different

Weakness- the likelihood of finding separated twins is small therefore it is unlikely this sort of study could be carried out and therefore no further psychological insights could be made into the effect of the environment alone on twins

Question 30

What are adoption studies useful for?

Answer 30

Adoption studies allow for psychologists to look for a genetic link by removing the environmental influence, as commonly children have both genes and environment in common with their biological parents

Question 31

How are adoption studies measured?

Answer 31

• Using a correlation technique- researchers looking for a correlation between the behaviour of the children and thisr parents
• similar to how twin studies are conducted looking for concordance rate between biological parents and the child

Question 32

Explain some strengths of using adoptive studies.

Answer 32

1) adoptive studies control for the environment as a confounding variable because the child is brought up in a different environment in a new way. If the child demonstrates behaviour that is more similar to biological parents, shows influence of genes, and if behaviour is more similar to adoptive parents, shows influence of environment
2) High ethics as adoptive studies usually proceed with the presumptive consent of the adoptive parents and biological parents if possible. The child’s anonymity is preserved and this respects their privacy and dignity
3) Highly beneficial to society as given that thousands of children are adopted every year (5330 UK 2015) they help us understand how much or how little adoptive parents can do for the children they are raising

Question 33

Explain some weaknesses of using adoptive studies.

Answer 33

1) The adoption process as a whole is a weakness as can lead to a range of different emotions which can influence children’s behaviour alone due to anxiety, becoming quieter, more aggressive, relieved, upset etc. Therefore lowers internal validity
2) Low generalisability= each adoption process and upbringing is completely unique and individual to the child. Therefore experience and therefore behaviour is difficult to draw trustworthy conclusions from which are applicable to all people
3) Adoption studies may create a rift in families, by drawing attention to the differences between adopted children and biological children

Question 34

What is the adoption study? State the aim, results and conclusion

Answer 34

Heston (1966)

• a study that aimed to see how many adopted children of biological mothers with schizophrenia would go on to develop schizophrenia themselves.
• results showed that 10% of the adopted children of schizophrenic mothers developed schizophrenia, providing evidence for the role of genes in schizophrenia.

Question 35

What is a correlation?

Answer 35

• a measurement of the extent to which pairs of related values on two variables tend to change together
• they describe the relationship between two variables in statistical terms, but is not a research method in itself

Question 36

What is a coefficient?

Answer 36

States the strength and which type of agreement between the two variables

Question 37

Explain what coefficients of +1, -1, and 0 mean

Answer 37

\+1 = a perfect strong positive correlation 
-1 = a perfect strong negative correlation 
0= no relationship at all 

-these are all extremely rare in psychology but tendency towards one gives us valuable information concerning the nature (positive or negative) and strengths (between 0-1) of the relationship between scores

Question 38

What is a curvilinear correlation?

Answer 38

-as one variable increases, so does another at the same rate until they reach a certain point, then both variables decrease at the same rate. (Forms an upside down U)

Question 39

Write a hypothesis for the following correlation= 
‘Investigating the influence student phone use in class has on exam performance’

Answer 39

There will be a negative correlation between student use on phone in class and their performance on an exam

Question 40

Explain 2 strengths of using correlations

Answer 40

1) Allow us to investigate otherwise unethical situations= using already existing groups of people in the environment to provide data
2) Control for participant variables= asking 1 person for 2 sets of data which then are compared, which eliminates individual differences

Question 41

Explain 2 weaknesses of using correlations

Answer 41

1) they can’t infer cause and effect= other factors/ extraneous variables can also influence the results, not 1 variable only causes effect
2) Problems using secondary data= data used to make correlation could be biased/ inaccurate/ originally used in another way