The Placebo Effect

The Placebo Effect


You may have heard about the placebo effect before and wondered what exactly it is and its importance in medical research. The activities in this lesson will help you learn about the placebo effect—what it is, what it has taught researchers about brain function, and why it is important for people to understand its potential impact on their lives.


During clinical trials, researchers typically divide participants into two groups—the experimental group and the control group. The experimental group receives the product being tested, while the control group receives a placebo, a physically inert substance identical in appearance to an active pharmacological medical treatment being investigated. Occasionally, active substances are used as placebos. These active placebos have side effects that mimic those of the drug being investigated but do not possess the physical properties hypothesized to produce the beneficial treatment effect.

This process illustrates scientific inquiry. Placebos are used so that the medical treatment being tested can be compared to another substance. The two groups being tested are virtually identical, which ensures that the test is valid. In such tests, the working hypothesis is that the treatment group will improve and the placebo group will not.

Go to the online selection entitled Hotel Maids Challenge the Placebo Effect. Answer the questions found on the Understanding the Placebo Effect student sheet and discuss them with your class.

To learn more about the placebo effect, read Your Health: The Placebo Effect and discuss it with your classmates.

Learn more about placebos by exploring these Web resources. Write down notes about the main points discussed on each site on your Understanding the Placebo Effect student sheet.

This esheet is a part of the The Placebo Effect lesson.

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