Question

Placebo's are sometimes used in research in order to demonstrate the effects of partipant expectations or beliefs on the outcome of behavior.

Answer 1

It's physics not biology.
and what is the question??

Answer 2

It's also used to determine whether a supposed medicine performs better than a placebo or not (double blind studies). The double blind studies are also used to test alternative medicine where it is shown that they don't do much better than the placebo effect.

Answer 3

Curiously, the placebo effect seems to work even when subjects are told they are getting the placebo.