Demand Characteristics in Psychology Experiments

In a psychological experiment, a demand characteristic is a subtle cue that makes participants aware of what the experimenter expects to find or how participants are expected to behave. Demand characteristics can change the outcome of an experiment because participants will often alter their behavior to conform to expectations.

How Do Demand Characteristics Influence Psychology Experiments?

In some cases, an experimenter might give hints or cues that might make the participant believe that a particular outcome or behavior is expected. It is important to note that the participant may or may not be right in their guess. Even if the individual is wrong about the experimenter's intentions, it can have a profound influence on how the participant behaves.

For example, the subject might take it upon themselves to play the role of the "good participant." Instead of behaving as they normally would, these individuals strive to figure out what the experimenter wants and then live up to these expectations. 

Demand characteristics might also motivate participants to behave in ways that they think are socially desirable (to make themselves look "better" than they really are) or in ways that are antagonistic to the experimenter (an attempt to throw off the results or mess up the experiment).

Example

In one classic experiment published in the journal Psychosomatic Medicine, researchers examined whether demand characteristics and expectations could influence menstrual cycle symptoms reported by study participants.

Some participants were informed of the purpose of the study and were told that the researchers wanted to look at menstrual cycle symptoms. The informed participants were significantly more likely to report negative premenstrual and menstrual symptoms than participants who were unaware of the study's purpose.

The researchers concluded that the reporting of symptoms was influenced by the demand characteristics as well as social expectations. In other words, people who thought that the researchers wanted to hear about some of the stereotypical symptoms of PMS and menstrual issues were more likely to say that they had experienced such negative symptoms while having their periods.

Dealing With Demand Characteristics

So how exactly do psychology experimenters go about reducing the potential impact of demand characteristics on their research results? Researchers typically rely on a number of different strategies to minimize the impact of demand characteristics.

Deception is a very common approach. This involves telling participants that the study is looking at one thing when it is really looking at something else altogether.

In other cases, researchers will minimize the contact that they have with study subjects. A double-blind study is a method used in which neither the participants nor the researchers interacting with them are aware of the condition to which the participants have been assigned. Having people who are not aware of the experimenter's hypothesis collect the data from participants helps reduce the chances that the subjects will guess what the study is about.

While it is not always possible to completely eliminate the chance that participants might guess what a study is about, taking a few of these precautions can help minimize the impact that demand characteristics will have on the research results.