From Traditional Medicine to Witchcraft: Why Medical Treatments Are Not Always Efficacious

Tanaka, M.M.; Kendal, J.R.; Laland, K.N.

doi:10.1371/journal.pone.0005192

From Traditional Medicine to Witchcraft: Why Medical Treatments Are Not Always Efficacious

Tanaka, M.M.; Kendal, J.R.; Laland, K.N.

Authors

M.M. Tanaka

Dr Jeremy Kendal jeremy.kendal@durham.ac.uk
Associate Professor

K.N. Laland

Abstract

Complementary medicines, traditional remedies and home cures for medical ailments are used extensively world-wide, representing more than US$60 billion sales in the global market. With serious doubts about the efficacy and safety of many treatments, the industry remains steeped in controversy. Little is known about factors affecting the prevalence of efficacious and non-efficacious self-medicative treatments. Here we develop mathematical models which reveal that the most efficacious treatments are not necessarily those most likely to spread. Indeed, purely superstitious remedies, or even maladaptive practices, spread more readily than efficacious treatments under specified circumstances. Low-efficacy practices sometimes spread because their very ineffectiveness results in longer, more salient demonstration and a larger number of converts, which more than compensates for greater rates of abandonment. These models also illuminate a broader range of phenomena, including the spread of innovations, medical treatment of animals, foraging behaviour, and self-medication in non-human primates.

Citation

Tanaka, M., Kendal, J., & Laland, K. (2009). From Traditional Medicine to Witchcraft: Why Medical Treatments Are Not Always Efficacious. PLoS ONE, 4(4), Article e5192. https://doi.org/10.1371/journal.pone.0005192

Journal Article Type	Article
Online Publication Date	Apr 15, 2009
Publication Date	Apr 15, 2009
Deposit Date	Jan 24, 2012
Publicly Available Date	Jan 24, 2012
Journal	PLoS ONE
Publisher	Public Library of Science
Peer Reviewed	Peer Reviewed
Volume	4
Issue	4
Article Number	e5192
DOI	https://doi.org/10.1371/journal.pone.0005192

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Copyright Statement
Copyright: © 2009 Tanaka et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.