Research Methods 6

Research Methods 6

1. Correlation analysis

   • non-experimental research method. It can be classed as a process rather than a method of study.
   • no manipulation of an IV
   • correlations measure the strength of a relationship between two co-variables (measurements).
   • use both primary and secondary data
   • correlations range from -1 to +1

2. Evaluation of correlations

   • + the data used in a correlation is quantitative. This means that the analysis can be conducted to test for statistical significance.
   • + if a correlation demonstrates a significant relationship then further research can be justified, therefore a correlation can act as a pilot study
   • + can be used when it is unethical or impractical to manipulate variables and can make use of secondary data.
   • - cause and effect cannot be established
   • - the measurements used to measure a relationship between variables may lack validity
   • - there may be other intervening variables that explain why the initial co- variables are linked

3. Brian scanning

   • CAT scans - also known as CT scans
     • use a series of X-ray beams passed through the head, creating cross-sectional images of the brain showing the STRUCTURE, but not the functions of the brain
     • + can be quick to conduct which can be useful if trying to determine if surgery is needed.
     • + helps surgeons to better plan a procedure before surgery takes place, as they can see accurate layout of brain structure before entering the skull
     • + could make the procedure faster and more efficient
     • + reduces the risk associated with longer duration under anaesthetic
     • - can expose individuals to a risk of radiation and should only be used when the benefits outweigh the costs.
     • - pregnant women are advised not to have CAT cans where possible as exposure can lead to pregnancy complications
   • PET scans
     • Injected with a substance known as flurodeoxyglucose (FDG), once the tracker is absorbed activities might be given. As the brain is working, the glucose will be used up and the radioactive atoms start to breakdown emitting positrons. During this process gamma rays are produced and it is this that the scanner picks up.
       • Warmer colours are a result of high activity and cooler colours are a result of lower activity
     • + Non- invasive way of studying inside the brain. The radioactive tracer is injected, which is invasive, but is less invasive than surgery.
     • + deemed to be valid because their findings do often match other findings and they do measure what they claim to measure.
     • + replicable and the same areas of the brain are highlighted
     • + allows researchers to see where the problem exists
     • - injection used may be distressing and may be deemed as unethical
     • - form of nuclear medicine - injecting patients/ participants with a small amount of radioactive material
   • FMRI scans
     • measures the brain activity, it works by detecting the changes in blood oxygenation and flow that occur in response to neural activity - when a brain area is mire active it consumes more oxygen and to meet this increased demand blood flow increases to the active area.
     • can be used to produce activation maps showing which parts of the brain are involved in particular mental process
     • + can noninvasively record brain signals without risk of radiation inherent in other scanning methods, such as CT or PET scans
     • + record signals form all regions of the brain, unlike EEG/ MEG - biased towards the cortical surface
     • + widely used and standardised data-analysis approaches have been developed which allow researchers to compare results across labs.
     • + produces compelling images of brain "activation"
     • - dispute over whether or not it actually measures what it claims to measure
     • - very noisy - makes it difficult to pick up changes in oxygenated blood flow
     • - images produced must be interpreted carefully