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Author: Ryan Backman

Identify placebos in experiments.

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Hi. This tutorial covers something called a placebo. Let's start with a definition. A placebo is a simulated and generally ineffectual treatment that is given to the participant that is not the actual treatment. Researchers often give a placebo to the control group as part of a blinded experiment.

Remember what a blinded experiment is. It is an experiment in which participants do not know what treatment they received. Sometimes when participants do know what treatment they receive. Sometimes there's bias that's introduced into the experiment. So placebos are, many times, used in a blinded experiment.

Specifically in medical experiments, a placebo is often a pill that looks like the treatment pill, but is devoid of any active ingredients. A placebo in a medical experiment could also be a cream, or an injection, or some other medical treatment that mimics the actual treatment. So a placebo's often needed in medical experiments because a person's beliefs can influence recovery from an illness.

So suppose researchers are conducting an experiment to evaluate the effectiveness of a new drug. So what they would do first is split up the group of subjects randomly into two groups-- a control group and a treatment group. And then this would be where the subjects do not know which group they're in. The drug would be given to the treatment group and the placebo-- that pill, or injection, or that cream-- would be given to the control group.

So they're getting this placebo treatment, instead of just nothing, like a control group usually gets. Now, often, when subjects receive a placebo drug-- and remember, they don't know that they're getting this placebo drug-- they will sometimes show improvement. Now, the reason this is happening is that the subjects believe the placebo's helping them. So this change in psychology affects the subject's hormones, which often improves the health.

So this is generally what's called the placebo effect. So now, after the subjects have been exposed to either the treatment or the placebo for a while, the researchers would measure improvement in both groups. If the treatment group does not show better results than the control, then the treatment is not shown to be effective.

So the placebo group provides a better basis for comparison than a no-treatment control group, and would allow the researchers to determine whether the treatment had any real effect over just the placebo effect. So that has been your tutorial on the placebo. Thanks for watching.

Terms to Know

An inert drug or treatment given to the control group. It has no active ingredient in it.

Placebo Effect

The observed phenomenon whereby certain individuals will exhibit a desired response even when taking a placebo, which contains no active ingredient.