Demand Characteristics 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. The presence of demand characteristics could even lead to the good subject effect, where participants are overly cooperative and behave in such a way that confirms the hypothesis of a study. Put another way, if an experiment suffers from demand characteristics, then its findings are considered neither valid nor meaningful. Demand characteristics can ruin an experiment.
Demand Characteristics Evidence
One study demonstrated how demand characteristics could influence the outcome of an experiment by recruiting participants for what they believed to be a sensory deprivation study. In this study, participants sat in a small but comfortable room for 4 hours. Participants in the experimental group, who were asked to sign a form releasing the experimenter from liability if anything happened to them during the experiment, and given a “panic button” to push if they felt overly stressed by the deprivation they were led to believe they would experience, exhibited signs of distress. Those in the control group, who did not sign a release form, were not given a panic button, and were not given the expectation that their senses were being deprived, did not exhibit signs of distress.
Reducing Demand Characteristics
There are several ways to reduce demand characteristics present within an experiment. One way is through the use of deception. Using deception may reduce the likelihood that participants are able to guess the hypothesis of the experiment, causing participants to act more naturally. Experimenters can also conduct a manipulation check, in which they ask participants what they thought the true purpose of the study was. This allows experimenters to assess whether or not participants correctly guessed the hypothesis of the study. A third way to reduce demand characteristics is to include a placebo control group in the experiment. Those in the placebo control group think they are receiving treatment (e.g., drug X), but in reality they are not (e.g., a sugar pill). Finally, experimenters can conduct field research, research that takes place outside of the laboratory in a real-world setting, to reduce demand characteristics.
- Orne, M. T. (1962). On the social psychology of the psychological experiment: With particular reference to demand characteristics and their implications. American Psychologist, 17,776-783.
- Orne, M. T., & Scheibe, K. E. (1964). The contribution of nondeprivation factors in the production of sensory deprivation effects: The psychology of the “panic button.” Journal of Abnormal and Social Psychology, 68, 3-12.