Controlling extraneous variables Flashcards
What is an extraneous variable?
A variable that might interfere with the effect of the IV on the DV and should be controlled or minimised
What is a confounding variable?
Extraneous variables that cannot be controlled or are forgotten about so they effect the DV (as if there is a second variable)
What are the types of extraneous variables?
Participant variables, situational variables and investigator effects
What are participant variables?
Individual differences (such as personality or emotions during the experiment) and participant reactivity (how they react to the experiment)
What are situation variables?
Variables from the research situation
What are investigator effects?
Unconscious bias from the investigator to ensure hypothesis is accepted such as expectancy effects, behaviour during research process or participants response to investigator as a person (can be minimised if same investigator is used)
What are examples of participant variables?
Age, motivation, personality, intelligence, concentration and gender
What are examples of situational variables?
Noise, weather, temperature, time of day and instructions
What are demand characteristics?
Cues in the research situation or from the investigator to reveal aim of the study which leads to unintended changes in participants’ behaviour, resulting in the Please-U (wanting to please experimenter) or Screw-U (wanting to ruin investigation) effect
What is randomisation?
The use of chance to reduce the effects of the researcher’s unconscious biases when designing an investigation
What is standardisation?
Making sure all the participants are subject to same instructions and experience
How do you control extraneous variables?
Use naïve participants who are unaware of research aim to prevent bias, use randomisation by mixing stimulus materials randomly, use standardisation to keep everything the same, use deception to hide aim of experiment to prevent Please-U or Screw-U effect and complete single/double blind trials to prevent bias
