Understanding the placebo effect from an evolutionary perspective

Pete C. Trimmer*, James A. R. Marshall, Lutz Fromhage, John M. McNamara, Alasdair I. Houston

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

11 Citations (Scopus)

Abstract

A placebo is a treatment which is not effective through its direct action on the body, but works because of its effect on the patient's beliefs. From an evolutionary perspective, it is initially puzzling why, if people are capable of recovering, they need a placebo to do so. Based on an argument put forward by Humphrey [Great expectations: the evolutionary psychology of faith-healing and the placebo effect. In: Humphrey, N (2002). The mind made flesh. Oxford University Press, Oxford. 255-285], we present simple mathematical models of the placebo effect that involve a trade-off between the costs and benefits of allocating resources to a current problem. These models show why the effect occurs and how its magnitude and timing can depend on different factors. We identify a particular aspect of belief which may govern the effect and conclude that a deeper understanding of why the placebo effect exists may allow it to be invoked more easily in the future. (C) 2013 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)8-15
Number of pages8
JournalEvolution and Human Behavior
Volume34
Issue number1
DOIs
Publication statusPublished - Jan 2013

Keywords

  • DEFENSE
  • STRESS
  • HEALTH
  • Belief
  • RESPONSES
  • IMMUNE-SYSTEM
  • Natural selection
  • NOCEBO PHENOMENON
  • Placebo
  • IMMUNOSUPPRESSION
  • BRAIN
  • Nocebo
  • Expectation
  • Evolution

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