Keywords: indipendent variable
Description: The independent variable is an essential part of any psychology experiment. By manipulating the independent variable, researchers can look at cause-and-effect relationships.
Kendra Cherry is an author and educator with over a decade experience helping students make sense of psychology. She is the author of the Everything Psychology Book (2nd Edition) and she has published thousands of articles on diverse topics in psychology including personality, social behavior, child therapy, research methods, and much more.
"Why is the independent variable labeled the independent variable? Because it is independent of research participants' actions - participants have no control over what condition or group they are assigned to. It is the experimenter who manipulates the independent variable, whereas participants have nothing to do with it (they are simply exposed to one version of the independent variable)."
"Independent variables are selected because an experimenter believes they will cause changes in behavior.
Increasing the intensity of a tone should increase the speed at which people respond to the tone. Increasing the number of pellets given to a rat for pressing a bar should increase the number of times the bar is pressed. When a change in the level (amount) of an independent variable causes a change in behavior, we say that the behavior is under the control of the independent variable."
"It is crucial that the experimental and control groups in a study be very similar, except for the different treatment that they receive in regard to the independent variable.
This stipulation brings us to the logic that underlies the experimental method. If the two groups are alike in all respects except for the variation created by the manipulation of the independent variable. then any differences between the two groups on the dependent variable must be due to the manipulation of the independent variable. "