Timeline of psychological experiments
An aim
hypotheses
directional hypotheses
(“one tailed”)
- used when you can know or predict from previous research which way this piece of research should go
- the researcher makes clear the sort of difference that is anticipated between two conditions or two groups of people
- generally, a directional hypothesis will include words such as higher, lower, less, more, faster, slower
- eg. people who drink red bull will be more talkative than people who don’t
non-directional
(“two tailed”)
- used when you don’t know which direction it is going in
- doesn’t state the direction of the research BUT states there will be a difference
- we usually use this if we don’t have any previous research in the area to base our prediction off
- eg. there will be a difference in chattiness dependent on whether people have red bull or water
independent variable (IV)
Dependent Variable (DV)
Levels of the Independent Variable
control condition
lacks any treatment or manipulation of the independent variable.
experimental condition
Operationalisation of Variables
Writing Hypotheses
how to identify an experiment hypothesis
how to identify a correlation hypothesis
sentence starter for experiment (directional) hypotheses
there will be an [increase/decrease/more/less/higher/lower] in..
sentence starter for experiment (non-directional) hypotheses
there will be a difference in…
sentence starter for correlation (directional) hypotheses
there will be a [positive/negative] relationship between…
sentence starter for correlation (non-directional) hypotheses
there will be a relationship/association between…
extraneous variables
participant variables
any individual differences between participants that may affect the DV
situational variables
any features of the experimental situation that may affect the DV
confounding variables
any variable, other than the IV, that may have affected the DV. They vary systematically with the IV (whereas extraneous do not).
features of confounding variables
demand characteristics
this is a type of extraneous variable… Any cue from the researcher or from the research situation that may be interpreted as revealing the purpose of the investigation. This can lead to participants changing their behaviour. Examples include the please-u and screw-u effect.