The Placebo Effect

The word placebo is derived from Latin and means “I shall please”. We apply the word placebo to anything that is used with the intent to deceive the recipient. In other words, placebos have no actual effect but we want the person to believe that the substance will help them. Placebos are used extensively in medical research to test the efficacy of the drug being tested. Stated another way, to test the efficacy of a drug, random volunteers are given the actual drug or a placebo that does not contain the drug but looks just like the drug being tested. These studies are done blind, meaning that the people involved do not know which drug is real and which drug is the placebo. It is expected that this sort of blind testing will prove if the drug actually works or not. Ironically, it was quickly discovered that if the person believes that the substance will help them, even if it contains only sugar, in many cases, it does! This phenomenon is called the placebo effect. The effectiveness of the placebo effect depends on many factors including:

  1. The personal beliefs and expectations of the person receiving the placebo
  2. Memories about therapies that the person believes have worked in the past
  3. Encouraging words given by people in authority such as doctors or other medical personnel
  4. Color, shape, smell, and taste of the placebo
  5. Interactions with other people who feel that the placebo treatment was effective
  6. The sight of health professionals, hospitals and medical instruments that reinforce the belief that the placebo is beneficial.

Below are some interesting studies illustrating the belief factors from the list above. See if you can determine which of the factors were used in each study to “deceive” the participants.