Methods - Biological psychology Flashcards
(12 cards)
What is correlation?
Correlation is a method used to assess the degree to which 2 co-variables are related
What are the advantages and disadvantages of correlation?
+ Easy to look at relationships between continuous variables and determining whether the relationship is significant or not
+ We can determine if there isn’t a casual relationship
- May be intervening variables that explain why the co-variables being studied are linked
- Method used to measure co-variable may lack reliability
What are the levels of measurement?
Nominal data - data is in separate categories
Ordinal data - data is ordered in some way
Interval data - data is measured using equal intervals
What is a CAT scan?
Uses X rays and computers to create detailed structured images of inside the body. Person lies in a rotating scanner that takes images from different angles.
+ Useful for revealing abnormal structures e.g. tumours
- Requires high radiation so can’t be used often
- Only provides structural information as only still images are produced
What is a PET scan?
Measures metabolic activity in brain. Injected with small amount of a radioactive substance
+ Shows brain in action which is useful for psychological research e.g. Volkow et al
+ Provide evidence of localisation of function
- Precise location of active areas are difficult to locate due to the carthomeatal line
- Radioactive substances cause damage to cell so unethical
What is an fMRI scan?
Uses radio waves to measure blood oxygen levels
+ Shows information about which areas of the brain are being used at any time
+ Extremely clear images
- Doesn’t use lots of radioactivity
- Expensive
- Only effective if the person stays completely still
What is a twin study?
Twin studies are where twins are compared on a specific trait to see how similar they are
What are advantages of disadvantages of twin studies?
+ Enables researchers to investigate influence of genes because its assumed that MZ and DZ co-twins share same environment
+ Information for twin studies is often taken from twin registries which means the sample is large and data is likely to be representative
- Twin studies may overestimate genetic influences
- Twin studies can’t identify specific genes involved
What is an example of twin studies?
-Gottesman and Shield (1996) investigated genetic basis of schizoprenia. A search through the record of about 45,000 psychiatric patients found 57 pairs of twins where at least one had schizoprenia. This is an opportunity sample.
- They contacted co-twins. Zygosity was determined by looking at our blood type. Therefore the researchers could identify MZ and DZ twins.
- If one twin had schizoprenia, their co-twin was 42x more likely to have schizoprenia than a person from general population. A DZ twin of same sex was 9x more likely to have schizoprenia if co-twin was diagnosed
What is an adoption study?
Where genetic factors are implicated if children are more similar to their biological parents with whom they share the same genes
Advantages and disadvantages of adoption studies?
+ Extraneous variables of environment can be removed
+ Useful in showing that twin studies overestimate genetic factors e.g. Eley et al
- Children may be adopted to families similar to their biological family therefore environmental influences may be similar
- Unlikely to be representative of wider population
What is an example of adoption study?
-Tienari et al conducted a Finnish adoptive family study looking at schizoprenia. They found lifetime schizoprenia risk for adopting children of biological mothers who had schizoprenia was 9.4%. The figure for adopted-away children of unaffected biological parents was 1.2%. This suggests genetic influences had an important role in schizoprenia.
