Lunch Talk: Placebo Effects.

UC Berkeley Cognitive Science C102, Lecture 6.

Expensive placebos work better than cheap ones.
Big placebo pills are more effective than little placebo pills.
Dark-colored placebo pills are more effective than light-colored placebo pills.
Placebo pills that taste bad are more effective than placebos that taste good.
Placebo delivered intravenously is more effective than a placebo delivered intra-muscularly.
Placebo delivered through a needle are more effective than delivered through the mouth.

If you tell somebody that you are giving him a placebo it stops being effective.