In an experiment, researchers manipulate one or more independent variables and examine the effect of these manipulations on one or more dependent variables. In the experiment we’ve just described, there was only one independent variable: the variations of the de- bate video, with each participant randomly assigned to one of the three versions. The dependent variable was the ratings of Reagan’s performance. It was the depen- dent variable because the researchers were interested in seeing if the ratings would depend on (that is, be influenced by) the manipulation of the independent vari- able (that is, by which version of the debate they watched).
independent variable In an experiment, a factor that experimenters manipulate to see if it affects the dependent variable.
dependent variable In an experiment, a factor that experimenters measure to see if it is affected by the independent variable.