The placebo effect occurs when a person experiences real symptom relief after taking an inactive substance believed to be medicine. A study published in the Journal of the American Medical Association (JAMA, 299(9):1016–1017, March 2008) showed that the perceived cost of a placebo can influence how strongly it seems to work.
In this experiment, 82 healthy volunteers were exposed to mild electrical shocks and then given an identical sugar pill described as a new pain medication. Participants were randomly assigned brochures stating the pill cost either $2.50 or $0.10 per dose. After taking the pill:
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85% of those told it was the higher-priced pill reported reduced pain
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61% of those told it was the low-priced pill reported reduced pain
Co-author Dan Ariely and colleagues noted that expectations shaped by cost and marketing cues can influence how people perceive symptom relief.
