Control of variables Flashcards
What are extraneous variables?
Any variable, other than the IV that could have an effect on the DV if it is not controlled properly.
What is randomisation?
The use of chance in order to control the effects of bias when designing materials and deciding the order of conditions.
What are investigator effects?
Any effect of the investigator’s behaviours (conscious and unconscious) on the research outcome (DV).
What are confounding variables?
Any variable, other than the IV that may have affected the DV so we cannot be sure of the true source of change to the DV.
Give some examples of investigator effects:
(The list is not finite)
- The design of the study.
- Selection of participants.
- Interactions with participants.
What is standardisation?
Using exactly the same formalised procedures and instructions for all participants in a research study.
What are demand characteristics?
Any cue from the researcher of research situation that may be interpreted by the participants as revealing the purpose of the investigation. This may cause the participant to change their behaviour within the research situation.
What is the difference between an extraneous variable and a confounding variable?
Extraneous variables do not vary systematically with the IV whilst confounding variables vary systematically with the IV.
Which variables are sometimes called ‘nuisance variables’?
Extraneous variables.
What type of variable is personality?
Confounding variable.
What are the two ‘effects’ of demand characteristics?
> Screw-U effect,
> Please-U effect.
What is the ‘screw-U effect’?
They deliberately under-perform to sabotage the results of the study.
Why are demand characteristics a problem for a study?
Because they mean that behaviour from the participants is no longer natural.
What type of variable is demand characteristics?
An extraneous variable.
What is the ‘please-U effect’?
They deliberately act in a way that they think is expected and over-perform to please the experimenter.
A leading question is an example of what variable?
It is a (conscious) investigator effect.
How did Loftus and Palmer demonstrate the effects of investigator effects in their ‘reconstruction of automobile destruction study’?
They showed the effects of leading questions, which are a type of investigator bias, they significantly altered EWT’s by changing one word in their question.
How can an investigator design their study to reduce investigator effects?
- Randomisation,
- Standardisation.
T / F:
Standardisation means that non-standardised changes in procedure do not act as extraneous variables.
True.
