Nocebos describes a sort of dark placebo effect:
The nocebo effect arises when you expect a poor health outcome, and then get one. For obvious reasons, nocebo effects are harder to test scientifically, because researchers do not wish to create them on purpose.Robert Ehrlich, in his Eight Preposterous Propositions, reports a few experiments. A group of hospital patients were given sugar water, and were told it would induce vomiting. Eighty percent of the patients vomited as a result.
Eighty percent of the patients vomited as a result. Crazy.
Many Chinese and Japanese people believe that the number four is unlucky. Scientists studied a sample of 200,000 such people, living in America. On the fourth day of the month, the death rate from heart attacks was thirteen percent higher.. In California, where Asian population concentrations might reinforce superstitious beliefs, the death rate on the fourth was twenty-seven percent higher. I wonder how many of the ‘heat deaths’ in Europe were accelerated, simply because some people thought they were supposed to be dying.