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Observer Expectancy Effect. The observer expectancy effect, also called the experimenter expectancy effect, is a phenomenon that can occur when a researcherâs beliefs or expectations cause him or her to unconsciously influence the participants of an experiment. In order to conserve the internal validity of an experiment, researchers can use a double-blind experimental design.
When we conduct experiments there are other variables that can affect our results, if we do not control them. The researcher wants to make sure that it is the manipulation of the independent variable that has changed the changes in the dependent variable.n an experiment, the researcher is looking for the possible effect on the dependent variable that might be caused by changing the independent variable. â¢ Independent variable (IV) : Variable the experimenter manipulates (i.e. changes) â assumed to have a direct effect on the dependent variable.