Answer: independent
Step-by-step explanation:
An independent variable remains under the control of the experimenter. The variable can be altered according to the desire of the experimenter. Thus the changes that occurred in the independent variable causes the changes in the dependent variable or experimental variable. The experimental variable is the outcome for the purpose of study.
The distance of the object is the independent variable, as this can be changed and will affect the fact that how the object is perceived which is the dependent or the experimental variable.