On This Page:ToggleSituational VariablesParticipant VariableExperimenter BiasDemand Characteristics
On This Page:Toggle
On This Page:
When we conduct experiments, there are other variables that can affect our results if we do not control them.
Anything that is not theindependent variablethat has the potential to affect the results is called an extraneous variable.
It can be a natural characteristic of the participant, such as intelligence level, gender, or age, for example, or it could be a feature of the environment, such as lighting or noise.
Purpose
The researcher wants to make sure that it is the manipulation of the independent variable that has an effect on the dependent variable.
Hence, all the other variables that could affect the dependent variable to change must be controlled. These other variables are called extraneous orconfounding variables.
Extraneous variables should be controlled where possible, as they might be important enough to provide alternative explanations for the effects.
Extraneous variables are factors other than the independent and dependent variables that may unintentionally influence the results of an experiment. They need to be controlled, minimized, or accounted for through careful experimental design and statistical analysis to avoid confounding the relationship between the independent and dependent variables.
Types
Situational VariablesSituational variables are factors, conditions, or characteristics related to the external environment that can influence a situation’s behavior, decision-making, or outcome.They are called “situational” because they are specific to a certain situation or context, as opposed to more stable, personal characteristics (like personality traits) that are relatively constant across situations.Examples of situational variables can range from physical aspects of the environment (like weather, location, time of day, or noise level) to social aspects (like the presence of others, group dynamics, or societal norms) to more abstract aspects (like time pressure, level of risk, or the clarity of instructions).Situational variables should be controlled so they are the same for all participants.Standardized procedures ensure that conditions are the same for all participants. This includes the use of standardized instructions
Situational Variables
Situational variables are factors, conditions, or characteristics related to the external environment that can influence a situation’s behavior, decision-making, or outcome.They are called “situational” because they are specific to a certain situation or context, as opposed to more stable, personal characteristics (like personality traits) that are relatively constant across situations.Examples of situational variables can range from physical aspects of the environment (like weather, location, time of day, or noise level) to social aspects (like the presence of others, group dynamics, or societal norms) to more abstract aspects (like time pressure, level of risk, or the clarity of instructions).Situational variables should be controlled so they are the same for all participants.Standardized procedures ensure that conditions are the same for all participants. This includes the use of standardized instructions
Situational variables are factors, conditions, or characteristics related to the external environment that can influence a situation’s behavior, decision-making, or outcome.
They are called “situational” because they are specific to a certain situation or context, as opposed to more stable, personal characteristics (like personality traits) that are relatively constant across situations.
Examples of situational variables can range from physical aspects of the environment (like weather, location, time of day, or noise level) to social aspects (like the presence of others, group dynamics, or societal norms) to more abstract aspects (like time pressure, level of risk, or the clarity of instructions).
Situational variables should be controlled so they are the same for all participants.
Standardized procedures ensure that conditions are the same for all participants. This includes the use of standardized instructions
Participant VariableThis refers to the ways in which each participant varies from the other and how this could affect the results, e.g., mood, intelligence, anxiety, nerves, concentration, etc.For example, if a participant that has performed a memory test was tired, dyslexic, or had poor eyesight, this could affect their performance and the results of the experiment. Theexperimental design chosencan have an effect on participant variables.Situational variables also include order effects that can be controlled using counterbalancing, such as giving half the participants condition “A” first while the other half gets condition “B” first. This prevents improvement due to practice or poorer performance due to boredom.Participant variables can be controlled usingrandom allocationto the conditions of the independent variable.
Participant Variable
This refers to the ways in which each participant varies from the other and how this could affect the results, e.g., mood, intelligence, anxiety, nerves, concentration, etc.For example, if a participant that has performed a memory test was tired, dyslexic, or had poor eyesight, this could affect their performance and the results of the experiment. Theexperimental design chosencan have an effect on participant variables.Situational variables also include order effects that can be controlled using counterbalancing, such as giving half the participants condition “A” first while the other half gets condition “B” first. This prevents improvement due to practice or poorer performance due to boredom.Participant variables can be controlled usingrandom allocationto the conditions of the independent variable.
This refers to the ways in which each participant varies from the other and how this could affect the results, e.g., mood, intelligence, anxiety, nerves, concentration, etc.
For example, if a participant that has performed a memory test was tired, dyslexic, or had poor eyesight, this could affect their performance and the results of the experiment. Theexperimental design chosencan have an effect on participant variables.
Situational variables also include order effects that can be controlled using counterbalancing, such as giving half the participants condition “A” first while the other half gets condition “B” first. This prevents improvement due to practice or poorer performance due to boredom.
Participant variables can be controlled usingrandom allocationto the conditions of the independent variable.
- Experimenter / Investigator Effects
The experimenter unconsciously conveys to participants how they should behave – this is calledexperimenter bias.
The experimenter is often totally unaware of the influence that s/he is exerting, and the cues may be very subtle, but they may have an influence nevertheless.
Also, the personal attributes (e.g., age, gender, accent, manner, etc.) of the experiment can affect the behavior of the participants.
- Demand Characteristics
Demand characteristicsare all the clues in an experiment that convey to the participant the purpose of the research. Demand characteristics can change the results of an experiment if participants change their behavior to conform to expectations.
Suppose we wanted to measure the effects of Alcohol (IV) on driving ability (DV). We would have to ensure that extraneous variables did not affect the results. These variables could include the following:
If these extraneous variables are not controlled, they may become confounding variables because they could go on to affect the results of the experiment.
Olivia Guy-Evans, MSc
BSc (Hons) Psychology, MSc Psychology of Education
Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.
Saul McLeod, PhD
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
