What is "demand characteristics"

n. (plural of demand characteristic English)Category:English plurals

In research—particularly psychology—demand characteristics refers to an experimental artifact where participants form an interpretation of the experiment's purpose and subconsciously change their behavior to fit that interpretation. Pioneering research was conducted on demand characteristics by Martin Orne. Typically, they are considered an extraneous variable, exerting an effect on behavior other than that intended by the experimenter.

A possible reason for demand characteristics is the participant's expectation that he or she will somehow be evaluated and thus figures out a way to 'beat' the experiment to attain good scores in the alleged evaluation. Demand characteristics cannot be eliminated from experiments, but demand characteristics can be studied to see their effect on the experiment. Examples of some common demand characteristics:

• Rumors of the study - any information, true or false, circulated about the experiment outside of the experiment itself.
• Setting of the laboratory - the location where the experiment is being performed, if it is significant.
• Explicit or Implicit communication - any communication between the participant and experimenter whether it be verbal or non-verbal that may influence their perception of the experiment.

Weber and Cook have described some demand characteristics as involving the participant taking on a role in the experiment. These roles include:

• The good-participant role in which the participant attempts to discern the experimenter's hypotheses and to confirm them. The participant does not want to “ruin” the experiment.
• The '''negative-participant role ''' (also known as the screw-you effect) in which the participant attempts to discern the experimenter's hypotheses, but only in order to destroy the credibility of the study.
• The faithful-participant role in which the participant follows the instructions given by the experimenter to the letter.
• The apprehensive-participant role in which the participant is so concerned about how the experimenter might evaluate the responses that the participant behaves in a socially desirable way.