a type of experimenter effect in which a researcher’s expectations about the findings of his or her research are inadvertently conveyed to participants and influence their responses. This distortion of results arises from participants’ reactions to subtle cues (demand characteristics) unintentionally given by the researcher—for example, through body movements, gestures, or facial expressions—and may threaten the ecological validity of the research. The term is often used synonymously with Rosenthal effect.