research methods Flashcards
describe how twin studies can be used to investigate human behaviour.
DZ twins share 50% of genetic material at most where as MZ share 100%. studying twins shows a lot about nature (genetics) and nurture (environment). if MZ and DZ twins behave the same then it suggests that nature is at work because the shared environment is not producing the same behaviour. twin studies are measures using statistical concordance rate meaning the level of ‘agreement’ this is usually expressed as a percentage. 100% means all the twins behaviour is shared in common and 0% means none of the behaviour is shared. Mz and DZ concordance rate is compared.
what are the strengths and weaknesses of twin studies. give two of each
identifying MZ and DZ lacks accuracy. Brendan et al assigned twins to MZ and DZ based on appearance so lacks validity. low generalisability, twins account for 1 in 65 births so a unique population size that live exceptional lives ie commonly mistaken for one another, dressed the same. so cannot establish generalisability to the rest of the population
naturally occurring variable MZ is 100% concordance and DZ is 50% concordance. researchers are not manipulating the variables themselves reduces bias. quantitative data has objectivity. produced as a percentage out of 100 so can easily be compared and analysed.
how do fMRI scans work. (4)
enable images of the brain to be produced without the use of radiation. brain activity is associated with blood flow to the brain. the information is gathered using a scanner. the patient is placed in a large scanner and a strong magnetic field is passed through the ppts head. it produces still images much like X rays. As neural activity increases, blood flowing to the active areas to keep up with the oxygen demand. changes in blood concentration can be detected by the scanner.
give 2 strengths and 2 weaknesses of fMRI scans
lacks generalisability. anyone with prosthetic limbs, pregnancy or claustrophobia cannot have this scan. so limited audience. they rely on ppts staying still ie not suitable for young children. movements can distort images and lacks validity when interpreting data.
high reliability as no exposure to radiation so can be replicated multiple times to ensure the same conclusions are made.objective data with high scientific rigour so can establish cause and effect. less subjective to researcher bias.
how do cat scans work.
like an x ray, sends radiation through the brain and gives external structure ie tumours - Charles Whitman.
give a strength and a weakness of cat scans
radiation exposure, cannot be replicated, lacks reliability.
how do pet scans work
your given a radioactive tracer, which goes to the brain and is broken down and metabolised. then a pet scan is carried out which can detect the areas of the brain that are most active ie red = active. blue= not active.
give a strength and a weakness of pet scans
radiation exposure, cannot be replicated, lacks reliability.
