Control Of Variables

Question 1

Extraneous Variables

Answer 1

The only thing that should influence DV is IV. Any other variables that might interfere with either should be controlled or removed. These variables are extraneous. Identified at start of study. Don’t vary systematically with IV. Makes it harder to detect result.

Question 2

Confounding Variables

Answer 2

Changes systematically with IV. Can’t control them.

Question 3

Demand Characteristics

Answer 3

Any cue from research situation that may be interpreted by participants as revealing investigation purpose. This may lead to a participant changing their behaviour within the situation. Look for clues on how to behave and so they would behave in order to please/displease the researcher. This is an extraneous variable

Question 4

Investigator Effects

Answer 4

Unwanted influence from investigator unconscious or conscious which would effect DV and research outcome. Eg: interacting with participants during exp.

Question 5

Randomisation

Answer 5

Used to minimise effect of confounding/extraneous variables on outcome. Used to control investigator effects. It should be random, not decided by the experimenter.

Question 6

Standardisation

Answer 6

All procedures should be standardised and have standardised instructions that are read to each participant. This means that non-standarised changes in procedure don’t act as extraneous variables.