research methods Flashcards
1
Q
fMRI scans
A
1) detects changes in blood flow & oxygenation that occur in response to neural activity
2) when brain area is more active, it needs more O2 so more blood with oxygenated haemoglobin flows to area
3) oxygenated blood repels but deoxygenated blood follows direction of magnetic field
4) scan can detect these diff magnetic qualities & so be used to create 3D map of brain
2
Q
PET scans
A
1) radioactive tracer is combined with flurodeoxyribose & injected into patient
2) after some time, p is placed in computer scanner
3) when H+ and e- collide gamma rays are emitted which are detected by the scanner
4) detected emissions are plotted (sometimes as a 3D plot) & brain activity is recorded
3
Q
PET & MRI strengths
A
- PET shows you chemical processes occuring in brain (eg: glucose uptake, raine 1997) unlike other methods & don’t need to stay really still like MRI
- fMRI scans are less invasive as emits less radiation & no injection SO good 4 patients that need multiple scans as lower risk of radiation damage eg: mutations, cancer
4
Q
fMRI - weaknesses
A
- temporal resolution (how quickly a scan takes to detect changes) is POOR (1-4 secs) - means can’t accurately use it to predict changes in brain & doesn’t provide direct measure of neural activity, just detects blood flow so diff 2 establish causation at neural level
5
Q
PET - weaknesses
A
- spatial resolution is poor (esp. in comparison to fMRI) so can’t detect really small measurements & more invasive as injection & radiation - due to risk which radioactive isotope causes can only be done a few times
6
Q
primary data
A
- original data that researcher has collected first hand from ps themselves spec. for study
- eg: experiments, questionnaires, observations
- adv: data has been specifically collected 4 study’s purpose, can ensure reliable & scientific methods have been used, & don’t have to sort through irrelevant info
- dis: takes a lot more time, £ & effort to collect data this way as you have to recruit your participants, carry out the experiment and then record your results
7
Q
secondary data
A
- data that already exist & has been examined (collected by someone other than original researcher)
- eg: psych journals articles, gov reports, pop records
- adv: doesn’t take as much time, effort or money as P.D
- dis: may not be relevant & quality of data will vary as some may be outdated, not useful or incomplete
8
Q
content analysis
A
- obeservational research where peepes are indirectly studied via communications (spoken, written or from media eg: newspapers)
- data is coded OR analysed 2 identify themes (key ideas)
- coding - qualitative into quantative & large data sets into meaningful units
- thematic analysis - produces descriptive, qualitative D
9
Q
random
A
- everyone in target pop is assigned a no
- random no. generator is used to select no.
- those with no. selected becomes part of sample
- adv - everyone has equal chance of being selected (unbiased), cheap & uncomplicated compared 2 others
- dis - sample chosen may not be rep of target pop, hard to get list of every individual when pop is large
10
Q
systematic
A
- get a list of target pop, choose starting point & select every nth person in pop (for sample)
- adv - unbiased as using objecteive system, prevents a cluster selection of ps as evenly selected
- dis - sample chosen may be unrepresentaive (by chance) & may be time consuming to create a list for large data sets
11
Q
volunteer
A
- ps choose/volunteer to be involved in study (eg: respond to ad)
- adv - more likely to consent as they’re coming to you & have access wide variety of ps (eg can post ads in multiple places) which could lead to more repsentation
- dis - ad may only attract certain types of people (eg: those interested in psych, highly motivated or desperate 4 £) & not be posted where everyone can see it
12
Q
snowball
A
- ps are recruited via word of mouth or from ps of study referring their aquaintances, used for research where ps are difficult to locate
- adv - researcher doesn’t have to spend as much time or effort recruiting ps, lower attrition rate as ps refer people they know will be committed, helpful in situations where ps are hesitant to participate & chain referal process allows psych to access pops that are difficult 2 sample
- dis - likely to end up with biased sample as ps will recruit people they know & thus likely share similar characteristics, referals may be unwilling to co-operate
13
Q
opportunity
A
- ask whoever is available at the time
- adv - quick, easy & cheap
- dis - likely to end up with biased sample as researcher will be more likely to recruit those they think will be helpful (researcher bias) & only choosing from small subgroup of target pop
14
Q
quota
A
- divide target pop into sub categories based on certain characteristics
- use non-random sampling technique (eg: snowball, opportunity) to choose ps from each group in proportion to how often they occur in pop
- adv - subgroups ensure sample is rep of target pop & non random methods tend to be more conveniant
- dis - non random methods are prone to bias & process time consuming & costly as involves lots of steps
15
Q
stratified
A
- divide target pop into sub categories based on certain characteristics
- use random sampling techniques (eg: random, systematic) to choose ps from each group in proportion to how often they occur in target pop
- adv - subgroups helps ensure sample is representative & random methods helps sample be unbiased
- dis - time consuming & costly as lots of steps involved & may end up with biased sample by chance
