Table of ContentsView AllTable of ContentsDependent and Independent VariablesIntervening VariablesExtraneous VariablesControlled VariablesConfounding VariablesOperationalizing VariablesFrequently Asked Questions

Table of ContentsView All

View All

Table of Contents

Dependent and Independent Variables

Intervening Variables

Extraneous Variables

Controlled Variables

Confounding Variables

Operationalizing Variables

Frequently Asked Questions

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Imagine you’re a researcher studying how sleep affects mood. To explore the connection, you would look at two key “variables”: sleep (how much someone gets) and mood (how happy or irritable they feel). In psychology research, variables allow researchers to study certain pieces of information and determine if changes in one lead to changes in another.

Variables in psychology are things that can be changed or altered, such as characteristics or values. Variables are generally used in psychology experiments to determine if changes to one thing result in changes to another.

Variables in psychology play a critical role in the research process. By systematically changing some variables in an experiment and measuring what happens as a result, researchers can learn more about cause-and-effect relationships.

The two main types of psychological variables are the independent and dependent variables. Both variables are important in collecting data about psychological phenomena.

Two of the most important variables you should learn about are an experiment’s independent and dependent variables. Sometimes, these are fairly easy to identify, particularly if the experiment is quite simple. However, this task can become more difficult as the complexity of an experiment increases:

The things that change, either naturally or through direct manipulation from the experimenter, are generally the independent variables. What is being measured? The dependent variable is the one that the experimenter is measuring.

Intervening Variables in Psychology

In the real world, variables often don’t stand alone. In many cases, factors affect the main variables of interest.

As a result, stress might be an intervening variable that influences how much sleep people get, which in turn may influence how well they perform on exams.

How Psychologists Use Experimental Methods

Extraneous Variables in Psychology

Independent and dependent variables are not the only variables present in many experiments. In some cases, extraneous variables may also play a role.

This type of variable may impact the relationship between the independent and dependent variables.

For example, in our previous example of an experiment on the effects of sleep deprivation on test performance, other factors such as age, gender, and academic background may have an impact on the results. In such cases, the experimenter will note the values of these extraneous variables so any impact can be controlled for.

There are two basic types of extraneous variables:

Other extraneous variables include the following:

Controlled Variables in Psychology

In the case of participant variables, the experiment might select participants that are the same in background and temperament to ensure that these factors don’t interfere with the results. Holding these variables constant is important for an experiment because it allows researchers to be sure that all other variables remain the same across all conditions.

It is important to also note that a controlled variable is not the same thing as acontrol group. The control group in a study is the group of participants who do not receive the treatment or change in the independent variable.

All other variables between the control group andexperimental groupare held constant (i.e., they are controlled). The dependent variable being measured is then compared between the control group and experimental group to see what changes occurred because of the treatment.

Confounding Variables in Psychology

If a variable cannot be controlled for, it becomes what is known as aconfounding variable. This type of variablecanhave an impact on the dependent variable, which can make it difficult to determine if the results are due to the influence of the independent variable, the confounding variable, or an interaction of the two.

Operationalizing Variables in Psychology

An operational definition describes how the variables are measured and defined in the study.Beforeconducting a psychology experiment, it is essential to create firm operational definitions for both the independent variable and dependent variables.

For example, in our imaginary experiment on the effects of sleep deprivation on test performance, we would need to create very specific operational definitions for our two variables. If ourhypothesisis, “Students who are sleep deprived will score significantly lower on a test,” then we would have a few different concepts to define:

Once all the variables are operationalized, we’re ready to conduct the experiment.

RecapVariables play an important part in psychology research. Manipulating an independent variable and measuring the dependent variable allows researchers to determine if there is a cause-and-effect relationship between them.

Recap

Variables play an important part in psychology research. Manipulating an independent variable and measuring the dependent variable allows researchers to determine if there is a cause-and-effect relationship between them.

Takeaways

Understanding the different types of variables used in psychology research is important if you want to conduct your own psychology experiments. It is also helpful for people who want to better understand what the results of psychology research really mean and become moreinformed consumers of psychology information.

While many people understand the basics of the independent and dependent variables, there are also less apparent variables that can affect experimental results. Intervening, extraneous, controlled, and confounding variables are just a few other factors that should be considered when assessing psychology research.

Frequently Asked QuestionsIndependent and dependent variables are used in experimental research. Unlike some other types of research (such ascorrelational studies), experiments allow researchers to evaluate cause-and-effect relationships between two variables.Researchers can use statistical analyses to determine the strength of a relationship between two variables in an experiment. Two of the most common ways to do this are to calculate a p-value or a correlation. The p-value indicates if the results are statistically significant while the correlation can indicate the strength of the relationship.In an experiment on how sugar affects short-term memory, sugar intake would be the independent variable and scores on a short-term memory task would be the independent variable.In an experiment looking at how caffeine intake affects test anxiety, the amount of caffeine consumed before a test would be the independent variable and scores on a test anxiety assessment would be the dependent variable.Just as with other types of research, the independent variable in acognitive psychologystudy would be the variable that the researchers manipulate. The specific independent variable would vary depending on the specific study, but it might be focused on some aspect of thinking, memory, attention, language, or decision-making.

Independent and dependent variables are used in experimental research. Unlike some other types of research (such ascorrelational studies), experiments allow researchers to evaluate cause-and-effect relationships between two variables.

Researchers can use statistical analyses to determine the strength of a relationship between two variables in an experiment. Two of the most common ways to do this are to calculate a p-value or a correlation. The p-value indicates if the results are statistically significant while the correlation can indicate the strength of the relationship.

In an experiment on how sugar affects short-term memory, sugar intake would be the independent variable and scores on a short-term memory task would be the independent variable.In an experiment looking at how caffeine intake affects test anxiety, the amount of caffeine consumed before a test would be the independent variable and scores on a test anxiety assessment would be the dependent variable.

In an experiment on how sugar affects short-term memory, sugar intake would be the independent variable and scores on a short-term memory task would be the independent variable.

In an experiment looking at how caffeine intake affects test anxiety, the amount of caffeine consumed before a test would be the independent variable and scores on a test anxiety assessment would be the dependent variable.

Just as with other types of research, the independent variable in acognitive psychologystudy would be the variable that the researchers manipulate. The specific independent variable would vary depending on the specific study, but it might be focused on some aspect of thinking, memory, attention, language, or decision-making.

Psychology Research Jargon You Should Know

6 Sources

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Andrade C.A student’s guide to the classification and operationalization of variables in the conceptualization and design of a clinical study: Part 1.Indian J Psychol Med. 2021;43(2):177-179. doi:10.1177/0253717621994334

Ulrich AK, Full KM, Cheng B, Gravagna K, Nederhoff D, Basta NE.Stress, anxiety, and sleep among college and university students during the COVID-19 pandemic.J Am Coll Health. 2023;71(5):1323-1327. doi:10.1080/07448481.2021.1928143

Yiping Z.Experimenter effect. In:The ECPH Encyclopedia of Psychology. Springer Nature Singapore; 2024:1-1. doi:10.1007/978-981-99-6000-2_755-1

American Psychological Association.Operational definition. APA Dictionary of Psychology.

Evans, AN & Rooney, BJ. Methods in Psychological Research. Thousand Oaks, CA: SAGE Publications; 2014.Kantowitz, BH, Roediger, HL, & Elmes, DG. Experimental Psychology. Stamfort, CT: Cengage Learning; 2015.

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