Definition

Demand characteristics are any aspect of an experiment that may reveal the hypothesis being tested or that may cue participants as to what behaviors are expected. Cues that may reveal the true purpose of an experiment can be embedded in information conveyed in the solicitation of participants, instructions given to participants, the tone of voice of the experimenter, gestures used by the experimenter, feedback given to participants (e.g., feedback about performance or personality characteristics), the laboratory setting, the design of the study, or rumors spread by others who have participated in the study.

The possibility that demand characteristics are present within a study is problematic. If participants guess what the hypothesis is, they might not act naturally, causing the results of the experiment to be inaccurate. ...