Hello. You did not present the experiment to which this question refers, which makes it impossible for me to give you an answer. However, when searching for your question on the internet, I was able to find another question exactly the same as yours, which showed that Rachel was studying the causes and consequences of treating mental illness in patients with generalized anxiety disorder. In this experiment, she gave each participant an untested drug, a placebo and a nocebo and assessed how these substances altered the arousal of the sympathetic nervous system one week before and one week after the study.
If that is the case with her question, the two reactions that Rachel could use to operate the dependent variable would be placebo and nocebo.
We can reach this conclusion because both the nocebo and the placebo do not generate real effects in the participants, but it causes psychological effects, imagined by the patient, against the real medicine. In this case, both the placebo and the nocebo are capable of provoking pisological effects in the excitation of the sympathetic nervous system of the patients. Within an experiment, the variable that has the power to provoke something is the independent variable and it is this variable that allows the researcher to operate the dependent variable. In this case, we can consider that the nocebo and the placebo are the independent variables that can manipulate the dependent variable, which is the sympathetic nervous system excitation.
