资料来源 : WordNet®

placebo effect
     n : any effect that seems to be a consequence of administering a
         placebo; the change is usually beneficial and is assumed
         result from the person's faith in the treatment or
         preconceptions about what the experimental drug was
         supposed to do; pharmacologists were the first to talk
         about placebo effects but now the idea has been
         generalized to many situations having nothing to do with
         drugs