research methods Flashcards
mainly definitions / mark scheme
directional hypothesis
a hypothesis that states the kind of relationship or difference between two variables eg coffee will have an effect on reaction time on ppts
non-directional hypothesis
a hypothesis that predicts that there will be a difference / relationship but does not state the kind of difference eg coffee will change reaction time on ppts
laboratory experiment
an experiment conducted in a controlled situation
validity
testing or measuring what you set out to measure
advantages of an experiment
- manipulation of IVS can indicate cause and effect relationships
- increased control and measurement so higher validity
- standardised procedures mean replication is possible, so higher reliability
disadvantage of an experiment
- artificial conditions = unnatural behaviour/demand characteristics so lack both external and internal validity
- results biased eg in sampling / experimental bias, reducing internal validity
- cannot control all variables
- ethical problems of deception
strength of lab experiment
high in internal validity as extraneous variables controlled, so can be confident that any observed change in DV is due to the IV
disadvantages of lab experiment
participants aware = demand characteristics, reducing ecological validity
- IV/DV may be operationalised and so doesn’t represent everyday experiences - so low in mundane realism
- ppts uncomfortable in unnatural environment
field experiment
an experiment conducted in a more natural environment, and participants are usually not aware that they are in an experiment
- IV is still manipulated so casual relationships between IV and DV still demonstrated
field experiment strengths
- high in ecological validity since ppts unaware that they’re being studied so no demand characteristics
- natural setting = ppts more relaxed
field experiment weaknesses
- IV still controlled so may lack mundane realism
- more difficult to control extraneous variables
- major ethical issues - ppts unknown of being studied, so difficult to debrief them - raises ethical issues with manipulating and recording their behaviour
- more expensive and time consuming
natural experiment
IV is not manipulated, instead it is naturally occurring but still a measure of what you expect to see
independent groups design
a ppt only does one experimental condition
repeated measured design
a ppt does both experimental conditions
matched pairs design
ppt matched on any variable of researchers choice eg iq, ethnicity, age, then randomly allocated to one of the two conditions
ABBA effect
- two groups splitting sample
- in group 1 each ppt does condition A (morning) then B (afternoon), in group two each ppt does B then A
- counterbalances order effects
RMD strengths
- same task used in both conditions so less time consuming and less money
- does not need as many ppts as IGD
- set variable to match ppts to
IGD strengths
- not subject to order effects
- set variable to match ppts to
IGD weaknesses
- you need twice as many ppts as RMD to end up with the same amount of data
- cannot control ppt variables
RMD weaknesses
- order effects eg practice effect
MPD weaknesses
time consuming and difficult to match all ppt variables as you can only match on variables known to be relevant
- very difficult to match key variables
avoid weaknesses of IGD
- make sure no one is more skilled in one variable over the other - ppts can be randomly allocated to distribute variables more evenly
avoid weaknesses of MPD
restrict number of variables to match to make things easier
RMD avoid weaknesses
counterbalancing/ABBA
random sampling
every member of the population has an equal chance of being selected
opportunity sample
selecting those from the population that are most easily available at the time of study eg walking by you on the street
stratified sample
identifying subgroups within a population eg gender/age, and obtaining ppts from each subgroup in proportion to their frequency in the population
ppts are randomly chosen
(division of a population into smaller subgroups known as strata)
systematic sampling
sampling method where researchers select members of the population at a set/regular interval (every nth person)
volunteer sampling
obtaining of ppts relies solely on volunteers to make up sample by advertisement
random sample - strengths
- unbiased as all members of population have an equal chance
random sample - weaknesses
- find every person of a population and contacting them is time consuming
opportunity sample - strengths
- finding convenient/suitable ppts takes a short time