Placebo: The Belief Effect
That biologically inactive substances, such as sugar pills and saline, can be as powerful as morphine, and that sham operations as effective real ones has been one of the most startling discoveries in recent biomedical science. The placebo effect, only acknowledged by the scientific community in the middle of the last century, is controlled for in trials, widely used to explain the effectiveness of supposedly non-therapeutic “treatments,” and sometimes used when we do not really want to treat a patient with drugs. However, for such a pervasive concept, little is understood about how it works.
Dylan Evans, a philosopher and “evolutionary roboticist” (I am not sure what that is either), however, has a theory as to the underlying mechanism of the placebo effect. To summarise his theory, only certain conditions are placebo responsive, and these all involve the acute phase response and innate immune system. The placebo response, Evans argues,