Controlling Variables (RM) Flashcards
What is a participant variables?
Variables which occur where individual characteristics of participants affect their behaviour in an experiment
E.g. age may be a confounding variables in an experiment about reaction of individuals to a light or noise stimulus as older people may have a slower reaction time than younger people (easily fixed by thinking about such factors when considering experimental design)
What is a situational design?
Variables which might affect the behaviour of the participant in the experiment but relate to the environment in which the experiment is taking place
E.g. if you were testing whether athletes train better by themselves or with another athlete, then it would be unfair to take measurements on days when the weather was very different. To control such situational variables the researcher should ensure that participants in each group undertake the task in the same situational conditions
What is an experimental variable?
A variable that occurs when the experimenter treats some participants differently to others. E.g The experimenters behaviour may be different which might then impact upon the DV. This is called experimenter bias(can be unconscious, experimenter may not realise)
To control this the researcher may provide the participants with written instructions to minimise contact between experimenter and participant. Or double blind trial
When is counterbalancing used?
Often used in repeated measures design when the same participants are used in all the conditions of the experiment.
Danger that order effects may affect the results
What are order effects?
Where behaviour is affected because participants take part in two or more conditions of an experiment and comprise of practice effect (the participants results are better when testing the second condition because of familiarity with the task), the fatigue effect (the participants’ results worsen across conditions because of tiredness or disinterest and recognising demand characteristics (features or cues is an experiment which help the participants work out what is expected of them during the experiment?
What is counterbalancing?
Simply means that the order in which participants undertake the different conditions of the experiment is varied to minimise the impact of order effects.
What is an example of counterbalancing?
If a participant is being used to test condition A and condition B. The researcher could get them to do the experiment ABBA whilst other participants completed the experiment BAAB to minimise practice and fatigue effects. This ensures that both conditions are affected by the order effects rather than one consistently benefiting one
What is standardisation?
It means making things the same across the variables. An experimenter might standardise factors such as the environment in which the participants undertake the experiment, use a standardised set of experiment instructions with every participant
This ensures that certain situational variables and experimenter variables do not affect the dependant variable and consequently the results.
What is randomisation?
The process of deciding the order or use of variables by chance
If researchers use chance to control variables, they cannot be accused of biasing the investigation
Assigning people in a research study to different groups without taking any similarities or differences between them into account
