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This article has been peer reviewed. It is the authors' final version prior to publication in Annals of Internal Medicine Volume 78, Issue 4, April 1973, Pages 595-598. The published version is available at PubMed ID: 4694043. Copyright © American College of Physicians


An overview of prescientific medicine, evolution, and individual human development is presented in an attempt to discover the generic factors operating in all interpersonal therapies. We hypothesize that the placebo effect rests on the universal human need for a group and, by symbolic extension, a system.