Demand Characteristics – Examples & Prevention

20.03.23 Research bias overview Time to read: 7min

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In research, there are many different things that can influence study outcomes. Especially, the different types of research bias can affect any study drastically, leading to invalid results. One of these biases is called demand characteristics, where the researcher’s expectations influence the answers of the participants. The following article will explain everything you need to know about demand characteristics and how to deal with them.

Demand Characteristics – In a Nutshell

Demand characteristics are expectations of the researcher that are guessed by the participants. This leads to them giving answers that may not be their true subjective opinion anymore but are influenced by the researcher’s.

Definition: Demand characteristics

Demand characteristics influence the participants, when they know or guess the intent of questions in the study. They are then more likely to give answers that will meet the expectations of the researcher. This is why the actual theme of the study is mostly kept secret, or a fake topic is told to the participants.

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Impact on participants

People taking part in your research may be able to determine its purpose from its presentation or location, which may impact their actions. This shift occurs because it is difficult to pretend to be ignorant once you have an idea of the experiment’s goal. There are four possible roles that study subjects might take in a given situation under the impact of demand characteristics.

The examples to illustrate the four types are based on a fictional study about how or if listening to music reduces stress.

The subject is eager to assist, so they offer to back up the scientist’s concerns.

Example

The good subject might, while listening to music, try extra hard to relax in order to produce satisfying results. And even if the music does not help them calm down, they might still report the opposite to help the researcher prove their objective.

The subject actively works to disprove the idea being tested.

Example

The negative subject will most likely reject listening to music, or do so unwillingly. They might, as they listen to music, even tense up or get annoyed because they are thinking about not wanting to do this.

The participant crafts the most popular responses possible to avoid negative feedback.

Example

The apprehensive subject would most likely also approve of the researcher’s theory. Music is a common way to relax, so they will answer that they actually felt calmer after enjoying music.

The participant does the task as though they were unaware of the study’s assumptions.

Example

The faithful subject in this case will sit down and listen to music, reflecting on themselves while doing so, to note down exactly what they are feeling. They try not to think about the objective and monitor what they are experiencing.

Sources

There are a few different types of demand characteristics, that may give away the research hypothesis and thus influence the responses of the participants.

  • Study rumors, inside and outside the study, might be one cause for demand characteristics. As participants may talk to one another before or after the trials, they naturally wonder what the objective is and thus create rumors about it. Some of these can actually be true and if the participants are wary of all possible options, they pay more attention to details.

Example

An example of a study rumor could be that in a study about how pets reduce stress level, participants pay closer attention to how they feel during the sessions. This can furthermore lead to observer bias, where they do actually feel more relaxed because they themselves expect to relax more around the animals too.

  • The experimental setting of the study can also hint about the objective and thus place demands on your participants, influencing their answers.

Example

For example, if you sample participants at a gym, they might suspect your study is about something related to fitness or health and thus give different answers than if you sampled them in a park.

  • The order of your procedure can also influence the participants, especially if the first few questions hint at your objective. People tend to form their impression of something rather quickly. If the start of your survey is about a certain topic, they will most likely believe that this is what the research is about and thus be influenced by demand characteristics.

Example

If the first few questions, for instance, are about eating habits and diet, the participants will believe that the study is about health or food.

  • The communication with your participants, whether it is conscious or subconscious, also highly influences their behavior and answers. Factors can be the phrasing of your question, your tone of voice, and even your facial expressions.

Example

After a participant answers a question, you might try not to let your opinion on that show in your response. However, many people pick up on small facial changes like a slight smile or frown that can give away how you feel about their answer.

  • The title and tools used for the study might also give away your hypothesis or objective, and should thus be chosen very carefully to not imply demand characteristics on your participants.

Example

For example, if your title gives away your whole topic, the participants will know what the study is about. Furthermore, depending on the tools you use, they will reflect on themselves more or less. If you record your interviews on camera, they will most likely watch their tone of voice as well as their expression and entire behavior. While, if you only record the audio, their actions will be more natural.

Consequences

Demand characteristics have different consequences on both internal and external validity of the study.

  • Internal validity is endangered if you are not able to tell whether your dependent variable changed because of the alternation in your independent variable or because of demand characteristics.
  • External validity gets reduced equally because if your results are not credible and generalized, the study may not represent the population anymore.

Controlling Demand Characteristics

Some careful planning and use of research tools will allow you to reduce the possibility of demand characteristics. Using these techniques, you may lessen the likelihood of demand characteristics influencing your study.

Deception

One possible way to control demand characteristics is deception, meaning you tell the participants a different objective than your actual one to avoid them searching for the actual hypothesis. It is ethically permissible to utilize deception in research if it is justified and will not cause any damage to the participants. When subjects finish the research, it is important to have a discussion with them to explain the study’s true objectives.

Example

Your objective is assessing the mood while listening to music. Participants are given a cover narrative to conceal the experiment’s purpose, saying that the study is on how various tones alter memory and give them filler memory tests that support your cover tale.

Between-Groups Designs

When testing treatments, study participants are often divided in an experimental group and a control group. Experiments with a within-group design have both treatment options in one group, meaning that the participants of experimental and control group know each other. This can lead to them comparing their treatments and finding out about the objective this way. To avoid demand characteristics, use a between-group design, where the experimental and control group are independent and separated.

Double-blind Design

A double-blinded study conceals who is in the experimental and control group from both the participants and the researcher. This way, the researcher cannot give away hints accidentally, keeping the study valid, and thus also reduces demand characteristics.

Examples

In clinical trials, medication is often tested by giving the real treatment to the experimental group while the control group gets a placebo. Neither the participants nor the doctors conducting the study know which participant gets which treatment. Thus, the study is called double-blinded.

Implicit Measurements

Implicit or hidden measurements in psychology reflect cognitive skills, characteristics, and behavior of participants that they may not be able to describe or recognize. When participants are unaware of the task, it can potentially conceal your study’s purpose.

Example

Instead of self-reporting mood, utilise an indirect measure. You estimate emotions using a word completion assignment. A participant’s mood may be determined from this metric. They will think this test assesses cognitive ability, but it measures emotions indirectly.

FAQs

Demand characteristics may reveal the goal of a study to participants. These signals might cause them to act differently dependent on their perception of the study.

Demand characteristics can change the behavior of study participants, causing them to respond in a non-natural way that warps the results of the research.

The probability of demand characteristics influencing your study can be reduced by deceiving the participants about the objective, using implicit measurements, making a double-blind study or using between-group design.

There are many reasons why demand characteristics can happen in a study. For example, rumors about the study’s goal can emerge from speculations, the order of procedure and setting can also give hints about your objective and even non-verbal communication is able to lead them onto your hypothesis.