One important experimental design in psychology is the placebo effect. Placebos are not real treatment, they are simply sugar pills that are given to patients in new drug trials to test how the real drugs work, or to see if the patients get better based solely on the fact that they are taking some kind of medication. The term placebo effect means improvement form the mere expectations of improvement. The fact that some patients get better while taking a placebo is due to some kind of confidence or calming influence, just because they think that they are being treated.
One of the most important factors in dealing with an experiment with a placebo is to make sure that the patients remain blind throughout the study. If the patients are not bling in the study, it will potentially mess up the results, as the different study groups will differ in their expectations of improvement. Two specific things can happen to ruin a study. First, the patients in the experimental group may improve faster than the patients in the control group receiving the placebo, because they are aware that they are receiving real treatment. Second, the control group may be disgruntled that they received the placebo, and they will then do everything they can to improve faster than those in the experimental group.
Overall, placebo effects can be very effective, and many show the same characteristics of actual drugs. Placebo effects are most useful in cases of depression and pain. However, they do not usually work well against illnesses such as cancer or heart disease. One other down side to placebo effects is that they do not last as long as actual medications.
Personally, I know that I always feel better after taking medication if I am sick, even though I'm not sure how much it really helps. To most people, placebo effects are hard to fathom. It brings up the question, how could it all be in my head? Most pains and sicknesses seem so real that we feel the need to take medication for it, when in reality medication may not always be the best answer.