Placebo

Definition

A placebo is an inactive substance or treatment given to a group of participants in an experiment to compare its effects with those of an active treatment. The purpose is to control for the psychological effects of receiving a treatment.

5 Must Know Facts For Your Next Test

1. Placebos are used as controls in experiments to help determine the actual effectiveness of the experimental treatment.
2. The placebo effect occurs when participants experience changes simply because they believe they are receiving a treatment.
3. Placebo groups help researchers isolate the physiological effects of the real treatment from psychological or other effects.
4. Blinding is often used alongside placebos to prevent bias; participants and sometimes researchers do not know who receives the placebo.
5. Ethical considerations must be taken into account when using placebos, especially in medical research.

Review Questions

• What is the primary purpose of using a placebo in an experiment?
• How does blinding enhance the validity of experiments involving placebos?
• What ethical issues should be considered when administering a placebo?

Related terms

Control Group:

A group in an experiment that does not receive the experimental treatment and is used as a benchmark to measure how the other tested subjects do.

Blinding:

A method used in experiments where information about which participants receive specific treatments is withheld to prevent bias.

Double-Blind Study: An experimental design where neither the participants nor the researchers know who belongs to the control group and who belongs to the experimental group, reducing bias.