Demand Characteristics | Definition, Examples, & Control
In research, demand characteristics are cues that might indicate the study aims to participants. These cues can lead participants to change their behaviors or responses based on what they think the research is about.
Demand characteristics are problematic because they can bias your research findings. They commonly occur in psychology experiments and social sciences studies because these involve human participants.
What are demand characteristics?
Demand characteristics are extraneous variables that can affect the outcomes of the study. These cues may nudge participants to consciously or unconsciously change their responses.
Sources of demand characteristics
In psychology experiments, demand characteristics can arise from many sources. Think of these as clues about the research hypotheses.
These sources include
- Title of the study on recruitment materials
- Rumors about the study
- Researcher’s interactions with the participant (e.g., a smile or a frown after a response)
- Study procedure (e.g., the order of tasks)
- Study setting (e.g., laboratory environment)
- Tools and instruments (e.g., video cameras, skin conductance measures)
These study characteristics place hidden ‘demands’ on participants to respond in a particular way once they perceive them. They can be subtle or obvious.
How do demand characteristics affect participants?
Based on your study materials or settings, participants might guess at the aim of the study, and their interpretations could influence their behaviors or responses.
The reason for this behavior change is simple: once you believe you know the aim of an experiment, it’s very hard to act as if you’re naive about it.
Sometimes, participants may actively play one of four roles.
|The participant tries to be helpful and confirm the researcher’s hypothesis
|The participant tries to act in ways that refute the researcher’s hypothesis—also called the ‘screw you’ effect
|The participant tries to produce the most socially desirable answers, out of fear of being judged
|The participant tries the act the way they would if they didn’t know the researcher’s hypothesis
Participants who play the role of a good subject try to use what they’ve learned to help you with your research. Acting in this way gives some participants a sense of fulfilment.
Conversely, participants in a negative subject role may try to actively sabotage your study by acting in unexpected ways or lying in their responses.
You may find some participants taking on this role out of frustration with being told what to do. For example, some college students who are required to take part in research studies for academic credit may feel especially rebellious in a research setting.
Why do demand characteristics matter?
Demand characteristics can invalidate research studies by providing an alternative explanation for the results. They pose a threat to both internal and external validity.
When you have demand characteristics, the internal validity of your experiment isn’t secure. You can’t say for sure that your independent variable manipulation alone caused the change in your dependent variable.
Instead, your participants’ reactions to the demand characteristics may have led to the results.
Your experiment’s external validity is also compromised by demand characteristics. The presence of these cues may mean that your findings can’t be generalised to people or settings outside of your study.
How do you control demand characteristics?
You can control demand characteristics by taking a few precautions in your research design and materials. These methods will help minimise the risk of demand characteristics affecting your study.
You can use deception to hide the purpose of the study from participants. Deception can mean keeping some information from participants or actively misleading them about the study tasks, materials, or aims.
Ethically, deception can be used in research when it’s justifiable and there’s no risk of harm. You should always debrief participants about the study’s real aims after they’ve completed it.
Many psychology studies use filler tasks and cover stories to misdirect participants.
Use a between-groups design
In quantitative research, you usually use either a between- or a within-groups design. While participants receive only one independent variable treatment in a between-groups design, they receive all independent variable treatments in a within-groups design.
You are more likely to risk having demand characteristics if you use a within-groups design. Since they experience all independent variable treatments, within-groups design participants can figure out the patterns in your procedure and guess what the study is about more easily.
Use a double-blind design
In a single-blind design, you know the participant’s condition assignment, while in a double-blind design, neither you nor the participants know the condition assignment.
You may have a greater risk of demand characteristics in a single-blind design compared to a double-blind design.
Use implicit measurements
In psychology, implicit (hidden) measures help you record cognitive abilities, traits, or behaviors that people may not be open about or able to report. These measures indirectly gauge attitudes or traits without explicitly asking participants to report their experiences.
Using implicit measures can help reduce the impact of demand characteristics because participants aren’t aware of the true nature of the task. These measures can also help you mislead them from the real aim of your study.
Other types of research bias
Frequently asked questions about demand characteristics
- What are demand characteristics?
In research, demand characteristics are cues that might indicate the aim of a study to participants. These cues can lead to participants changing their behaviors or responses based on what they think the research is about.
Demand characteristics are common problems in psychology experiments and other social science studies because they can bias your research findings.
- Why do demand characteristics matter in research?
These cues may nudge participants to consciously or unconsciously change their responses, and they pose a threat to both internal and external validity. You can’t be sure that your independent variable manipulation worked, or that your findings can be applied to other people or settings.
- How do I prevent demand characteristics?
Use these measures:
- Deception: Hide the purpose of the study from participants
- Between-groups design: Give each participant only one independent variable treatment
- Double-blind design: Conceal the assignment of groups from participants and yourself
- Implicit measures: Use indirect or hidden measurements for your variables
- What are the types of extraneous variables?
There are 4 main types of extraneous variables:
- Demand characteristics: Environmental cues that encourage participants to conform to researchers’ expectations
- Experimenter effects: Unintentional actions by researchers that influence study outcomes
- Situational variables: Eenvironmental variables that alter participants’ behaviours
- Participant variables: Any characteristic or aspect of a participant’s background that could affect study results
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