Extraneous variable definition: a variable not being investigated that has the potential to affect the outcome of a study
Participant variables:
age
motivation
personality
gender
intelligence
Situational variables:
weather
lighting
instructions
time of day
noise
Demand characteristic definition: an experimental artefact where participants form an interpretation of the experiment's purpose and unconsciously change their behaviouraccordingly
Demand characteristic example

people trying to work out the aim of a study
How can demand characteristics be controlled?
by deceiving participants and not telling them the true aim of the study
Investigator effect definition: subtlecues or signals from an experimenter that can affect the performance of participants in a study
