# Biological Psychology- Methods

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What is a correlation?
A relationship between 2 variables, so correlational research measures 2 different variables to investigate their relationship
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Why do scientists use correlational studies rather than other types of experiments?
Easier to find relationships, it is usually quicker and cheaper
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Why are the variables called co-variables and not IV and DV?
Not dealing with cause and effect relationships, only seeing if there is a link so variables, psychologists aren't able to manipulate one into different levels or conditions
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Give an example of a positive co-cariable correlation
Height and weight
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What does the coefficient tell us?
The direction and strength of a correlation
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Give an example of a strong negative coefficient and a weak positive
S.N= -0.9, W.P= +0.1 (Strongest negative= -1, strongest positive= +1)
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When do we used Spearman's Rank?
In a correlational study
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How do we know if the results are significant?
Work out your observed value from the formula, compare observed value (Calculated coefficient) with critical value, if OV is greater than CV, you reject the null hypothesis of there not being a correlation
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Advantages of Correlational Research
Study relationships of variables which would be unethical to manipulate, gathers a lot of info, further investigation is required after a correlation is found
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Disadvantages of Correlational Research
Correlation doesn't imply causation, relationships can be misread, direction of causation my be misread (what causes what), intervening variables may play a role
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CAT scans
X-ray, cross sectional imaging so 3D image, shows structure not function
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PET scans
Shows actively i brain, injected with radio active dye, positrons detected from dye, colour image
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fMRI scans
Less invasive, no radiation, monitors blood flow in brain, detects changing levels with electromagnet
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Strengths and weaknesses of CAT scans
S- Quick, Accurate detail W- Exposure to radiation, shows structure not function
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Strengths and weaknesses of PET scans
S- can predict issues, see where the problems are W- Invasive, not advisable for patients to have too many
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Strengths and weaknesses of fMRI scans
S- Non-invasive, no associated risks (e.g. radiation) W- Claustrophobic setting can cause panic, certain people can't have them (e.g. people with pacemakers)
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What is a twin study?
A study using 2 types of twins so see if there is a genetic causation for a certain thing or not
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What is a monozygotic (MZ) twin?
Identical twins who share 100% of their genetics with each other
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What is a dizygotic (DZ) twin?
Non-identical twins who only share 50% of there genetics
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Name a twin study and what did they find?
Gottesman and sheilds, twin study into schizophrenia, observed loads of MZ and DZ twins over 16 years, found that the MZ twin that had it, 42% of their co-twins would have it, compared to the 9% of DZ's,
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What are adoption studies?
A type of study which compares genetic and environmental factors, observes adoptee and then their adoptive patent and their natural parents to see if they developed whatever from environment or genetics
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Describe an adoption study
Cadoret and Stewart- See if adopted boys had ADD and aggression with convicted natural parents, they found that it may be genetic because even though they weren't brought up with that, they were more likely to be aggressive and be diagnosed with ADD
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## Other cards in this set

### Card 2

#### Front

Why do scientists use correlational studies rather than other types of experiments?

#### Back

Easier to find relationships, it is usually quicker and cheaper

### Card 3

#### Front

Why are the variables called co-variables and not IV and DV?

### Card 4

#### Front

Give an example of a positive co-cariable correlation

### Card 5

#### Front

What does the coefficient tell us?