Placebo

a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient. Sometimes patients given a placebo treatment will have a perceived or actual improvement in a medical condition, a phenomenon commonly called the placebo effect. In medical research, placebos are given as control treatments and depend on the use of measured deception. http://en.wikipedia.org/wiki/Placebo

cf

• Scientific Method
• Cargo Cult
• Hawthorne Effect http://en.wikipedia.org/wiki/Hawthorne_effect
• Nocebo http://science.slashdot.org/story/12/08/10/2217238/beware-the-nocebo-effect