Demand characteristics refer to behavior that can sometimes be exhibited during psychological experiments. This occurs when a person who is involved in an experiment has been influenced in someway. The psychologist or person giving the test can give subtle hints or clues as to the outcome of the test and what is to be expected. Instead of giving an honest answer, the person being tested may change some or all parts of the answer to conform to what the tester is looking for. Demand characteristics can change behaviors to seem more socially or morally responsible.
There are many psychological examinations or tests that are performed for various reasons but the outcomes of these experiments can be one way to know more about how people react to different situations. The outcome is not only based on the situation or experiment but on what the person is told or sees while going through the test. A psychologist may unintentionally put an emphasis on an idea or make a statement that leads the person to conform to a certain idea. Visual manipulations can also be used to alter an opinion or interpretation. All of these things are considered demand characteristics and if any type of experiment or evaluation is done under these circumstances, it is not considered valid.
A good example of demand characteristics can be seen in a study done on motion sickness. People were asked to fill out a questionnaire on the effects of motion and a percentage merely filled out the form. The remaining people being tested were placed in an environment with visually stimulated motion. Not only were the questions answered differently but the people who were placed in the environment also felt motion sickness. Responses to the questionnaire varied greatly when other stimuli were introduced.
Word usage also can determine demand characteristics. A simple idea can be presented for interpretation but by adding a phrase or ending to a question, it can have a considerably different answer as a result. For example, when a group of women were asked about menstruation they answered a certain way. Another group of women were asked the same question but they were also asked about symptoms that accompanied menstruation. These women had a much higher complaint rate than the women in the first study.
When demand characteristics have negatively influenced a decision, it is considered biased. People can conform to a certain principle or idea if they are led to believe that there is only one viable solution. They also conform if it gives them a more favorable self image.