methodologies knowledge Flashcards
brain scans, longitudinal studies, cross-sectional studies
CT Scan
set of x-rays combined together to form 2D or 3D images
of the area of the brain that is being scanned.
* Before x-rays ,radioactive dye is injected into the
patient
- cross-sectional images of the brain showing the structure,
but not the function.
PET Scan
patient given a radioactive glucose (sugar).
* Areas of the brain that appear to be more active are the areas
which require the most glucose.
* The detectors in the scanner can highlight the most active areas of
the brain, allowing an in-depth image of what the brain activity is
like
longitudinal studies
: a study conducted over a long period of
time.
* Participants are assessed on two or more occasions as they get
older.
* This allows the researcher to investigate any long-term effects (e.g.
how memory gradually decreases with age).
cross-sectional studies
one group of participants representing
one section of society (e.g. young people or working-class people) are
compared with participants from another group (e.g. old people or
middle-class people).
strength of CAT Scans
- High quality images, better than those
produced by x-ray alone. - They can reveal structures in the brain that
appear abnormal e.g. tumours.
weakness of CAT Scans
- Only provide a researcher with the structure of the brain, not the electrical
activity of the brain. - Exposure to radiation: the more detailed the scan is, the more radiation an
individual is exposed to.
strengths of PET Scans
- Only PET scans allow researchers to see
chemical activity in the brain. - Useful for psychological research as they
look at more active brain areas.
weakness of PET Scan
- Costly to run and maintain, meaning there
is limited availability for research. - Not as precise as scans such as an MRI.
strength of Longitudinal studies
- The same person is tested numerous times
so participant variables are controlled. - High attrition rate because the research
takes so long.
weakness of Longitudinal studies
- Developmental trends can be spotted as
tests are repeated at regular intervals. - Participants are more likely to be aware
of the aims of the study so may show demand characteristics.
strength of cross-sectional studies
- Relatively quick and cheap because
participants only need to be tested once
for comparisons. - Participants are easier to obtain because
there’s less pressure for them to take part,
compared to having to stick with a longterm longitudinal study.
weakness of cross sectional studies
- Difficult to determine why there are differences between the two cohorts as participants cannot always be asked about
the differences. - Data collected is from a snapshot in time,
so it’s harder to identify and analyse developmental trends in these studies.
MRI
very detailed images of brain
use magnetic fields to generate data so patients not exposed to radiation
fmri shows function and structure
disadvantages of MRI
extremely loud process
circular chamber can cause individuals to feel claustrophobic
time consuming comparison to others
advantages of MRI
patient not exposed to radiation
can give structcure and function