Research methods- Biological Approach Flashcards
What are brain scanning techniques used for?
To research the structure and function of the brain.
What does CAT scan stand for?
Computerised Axial Tomography
What are CAT scans?
Involves passing X-rays into the head and multiple beams are passed around the head from different angles to gather more information.
What are CAT scans useful for?
Detecting areas of the brain damage following an accident or the positioning of tumours in the brain.
What are CAT scans not useful for?
Giving us information about how the brain is functioning.
What are some strengths of CAT scans?
- For revealing abnormal structures in the brain such as tumours in the brain or structural damage.
- High quality of the images.
- Help surgeons better plan a procedure before surgery takes place.
What are some weaknesses of CAT scans?
- Require more radiation.
- Only provide structural information.
What does PET scans stand for?
Positron Emission Tomography.
What are PET scans?
A form of nuclear medicine procedure as they involve injecting the patient with a small amount of radioactive material in order to conduct the scan.
What are PET useful for?
Investigating areas of the brain that are not functioning normally, which could indicate damage or tumours.
What are some strengths of PET scans?
- Show brain in action, useful for psychological research.
- Indicate the specific areas of the brain.
What are some weaknesses of PET scans?
- At times results are not easy to interpret.
- Precise location of active areas in relation to brain structure is difficult to pinpoint.
- Radioactive substances cause damage to the tissue of the body. (ethical issues).
What does fMRI scans stand for?
Functional Magnetic Resonance Imaging.
What are fMRI scans?
Enables images of brain activity to be gathered without the use of radiation.
What are some strengths of fMRI scans?
- Shows important information about which areas of the brain are being used at any one time.
- Safe method, as it doesn’t use radiation.
- Doesn’t involve injections, so it’s non-invasive.
- Images extremely clear.
What are some weaknesses of fMRI scans?
- Only effective if the person whose being investigated stays perfectly still, and this may be a problem for (e.g.) children.
- 5 second time lag between brain activity and image appearing on screen which can cause problems when trying to interpret the info received.
- People with metal surgical implants, may be unable to have this kind of brain scan because of the high-powered magnetic fields.
What is a twin study?
Where twins are compared on a specific trait to see how similar they are.
What are the two types of twins?
Monozygotic twins and Dizygotic twins.
What are Monozygotic twins?
- identical
- share 100% of their genes.
What are Dizygotic twins?
- non- identical
- share 50% of their genes (like any other siblings).
What does correlation mean?
If we are looking at a behaviour measured numerically, we can calculate a correlation coefficient to measure similarity.
What does concordance rate mean?
If we are studying a behaviour which is all or nothing, we use a concordance rate which is the percentage of those studied are concordant (similar).
What is an example of correlation?
IQ
What is an example of concordance rate?
Whether someone has been diagnosed with schizophrenia or not.
What is an example of a twin study?
Gottesman and Shields (1966).
What is the conclusion from the study of Gottesman and Shields (1966)?
There may well be a genetic element that could explain why people develop schizophrenia.
Why can’t we say schizophrenia is completely genetic?
Because the concordance rates for the Monozygotic twins wan not 100%.
What are two strengths of twin studies?
- Enables researchers to investigate the influence of genes because it is assumed that both MZ and DZ twins share the same environment.
- The sample is large and data is likely to be representative.
What are two weaknesses of twin studies?
- Twins studies may overestimate genetic influence.
- Twin studies provide a very broad indication that a behaviour has a genetic origin, but they cannot identify the specific genes involved.
What are adoption studies?
Adopted children are compared with 1) biological relative i.e biological parent and 2) adoptive relative i.e adoptive parent or sibling.
What is an example of an adoption study?
- Heston (1966)
What is the conclusion of Heston (1966)?
The finding’s support the influence of genes in schizophrenia.
What are two strengths of an adoptive study?
- Has the advantage of removing the extraneous variable of environment.
- Useful in showing that twin studies overestimate genetic factors.
What are two weaknesses of an adoptive study?
- Apparent similarities with biological relatives relatives may be due to environmental similarities rather than genes.
- People who adopt other people’s biological offspring may not be representative of the population.
What are the three types of correlations?
- Positive correlation
- Negative correlation
- No correlation.
What is a positive correlation?
As one variable increases, the other variable also increases but necessarily at the same rate.
What is a negative correlation?
As one variable increases, the other variable decreases but not necessarily at the same time.
What does no correlation mean?
There is no relationship between the two variables.
What is a correlation?
A way of measuring the relationship between co-variables, instead of looking at the difference. (i.e. in an experiment)
What is a scatter diagram?
Used to illustrate a correlation between 2 co-variables (display it visually in graph form).
What is a correlation co-efficient?
- Helps us know if the pattern of dots on a scatter graph represents a meaningful association.
- Measures the strength of the relationship between the co-variables.
