research methods

• an extraneous variable is any variable other than the independent variable that may have an effect on the dependant variable if controlled.
• A confounding variable is a variable related to the independent variable. It might be the confounding variable, rather than the independent variable that affects the dependent variable.
• demand characteristics are when there are no cues or clues that can reveal the experimental aims.
• The investigator effect is a specific type of demand characteristic related to the behaviour of the researcher, potentially posing a bias to the experiment unknowingly.