Unintended consequences

From Wikipedia, the free encyclopedia - View original article

Jump to: navigation, search
This article is about the ethical concept. For the novel, see Unintended Consequences (novel).
An erosion gully in Australia caused by rabbits. The release of rabbits in Australia for hunting purposes has had serious unintended ecological consequences.

In the social sciences, unintended consequences (sometimes unanticipated consequences or unforeseen consequences) are outcomes that are not the ones intended by a purposeful action. The term was popularised in the 20th century by American sociologist Robert K. Merton.[1]

Unintended consequences can be roughly grouped into three types:


The idea of unintended consequences dates back at least to Adam Smith, the Scottish Enlightenment, and consequentialism (judging by results).[2] However, it was the sociologist Robert K. Merton who popularized this concept in the twentieth century.[1][3][4][5]

In his 1936 paper, "The Unanticipated Consequences of Purposive Social Action", Merton tried to apply a systematic analysis to the problem of unintended consequences of deliberate acts intended to cause social change. He emphasized that his term "purposive action... [is exclusively] concerned with 'conduct' as distinct from 'behavior.' That is, with action that involves motives and consequently a choice between various alternatives".[5] Merton also stated that "no blanket statement categorically affirming or denying the practical feasibility of all social planning is warranted."[6]

More recently, the law of unintended consequences has come to be used as an adage or idiomatic warning that an intervention in a complex system tends to create unanticipated and often undesirable outcomes.[7][8][9][10] Akin to Murphy's law, it is commonly used as a wry or humorous warning against the hubristic belief that humans can fully control the world around them.


Possible causes of unintended consequences include the world's inherent complexity (parts of a system responding to changes in the environment), perverse incentives, human stupidity, self-deception, failure to account for human nature or other cognitive or emotional biases. As a sub-component of complexity (in the scientific sense), the chaotic nature of the universe—and especially its quality of having small, apparently insignificant changes with far-reaching effects (e.g., the butterfly effect)—applies.

Robert K. Merton listed five possible causes of unanticipated consequences in 1936:[11]

  1. Ignorance, making it impossible to anticipate everything, thereby leading to incomplete analysis
  2. Errors in analysis of the problem or following habits that worked in the past but may not apply to the current situation
  3. Immediate interests overriding long-term interests
  4. Basic values which may require or prohibit certain actions even if the long-term result might be unfavorable (these long-term consequences may eventually cause changes in basic values)
  5. Self-defeating prophecy, or, the fear of some consequence which drives people to find solutions before the problem occurs, thus the non-occurrence of the problem is not anticipated


Unexpected benefits[edit]

Unexpected drawbacks[edit]

Perverse results[edit]

Unintended consequences of environmental intervention[edit]

Because of the complexity of ecosystems, deliberate changes to an ecosystem or other environmental interventions can have unintended consequences. Sometimes, these effects cause permanent irreversible changes. Examples include:

See also[edit]


  1. ^ a b Robert K. Merton, Versatile Sociologist and Father of the Focus Group, Dies at 92, Michael T. Kaufman, The New York Times
  2. ^ Adam Smith The Theory of Moral Sentiments p. 93.
  3. ^ Renowned Columbia Sociologist and National Medal of Science Winner Robert K. Merton Dies at 92 Columbia News
  4. ^ Robert K. Merton Remembered Footnotes, American Sociological Association
  5. ^ a b Merton, Robert K. "The Unanticipated Consequences of Purposive Social Action". American Sociological Review 1 (6): 895. doi:10.2307/2084615. Retrieved 2008-05-30. 
  6. ^ Merton, Robert K. "The Unanticipated Consequences of Purposive Social Action". American Sociological Review 1 (6): 904. doi:10.2307/2084615. Retrieved 2008-05-30. 
  7. ^ Norton, Rob (2008). "Unintended Consequences". In David R. Henderson. Concise Encyclopedia of Economics (2nd ed.). Indianapolis: Library of Economics and Liberty. ISBN 978-0865976658. OCLC 237794267. 
  8. ^ "HeinOnline". HeinOnline. Retrieved 2010-05-07. 
  9. ^ "28 Florida State University Law Review 2000-2001 Mandatory Minimum Sentences: Exemplifying the Law of Unintended Consequences Comment". Heinonline.org. 1993-06-18. Retrieved 2012-11-21. 
  10. ^ "HeinOnline". HeinOnline. Retrieved 2010-05-07. 
  11. ^ Merton, Robert K (1996). "On Social Structure and Science". The University of Chicago Press. Retrieved 2012-11-21. 
  12. ^ "From Iron Curtain to Green Belt: How new life came to the death strip". London: Independent.co.uk. 2009-05-17. Retrieved 2010-05-07. 
  13. ^ Kate Connolly (2009-07-04). "From Iron Curtain to Green Belt". London: Guardian. Retrieved 2010-05-07. 
  14. ^ "European Green Belt". European Green Belt. Retrieved 2010-05-07. 
  15. ^ "Maryland Artificial Reef Initiative Celebrates 1 Year Anniversary". Dnr.maryland.gov. 2008-02-07. Retrieved 2010-05-07. 
  16. ^ 4:00 p.m. ET (2007-05-25). "Sinking ships will boost tourism, group says – News – msnbc.com". MSNBC. Retrieved 2010-05-07. 
  17. ^ "Life after death on the ocean floor – The National Newspaper". Thenational.ae. 2009-09-21. Retrieved 2010-05-07. 
  18. ^ "Sea Life Flourishing On Vandenberg Wreck Off Keys". cbs4.com. 2009-10-15. Retrieved 2010-05-07. 
  19. ^ "CDNN :: Diver Wants to Sink Old Navy Ships off California Coast". Cdnn.info. 2006-12-27. Retrieved 2010-05-07. 
  20. ^ "BBC 15 February 2001, Aspirin heart warning". BBC News. 2001-02-15. Retrieved 2010-05-07. 
  21. ^ Clive Feather (25 April 1996). Peter G. Neumann, ed. "AOL censors British town's name!". ACM Committee on Computers and Public Policy. 
  22. ^ Cockburn, Craig (9 March 2010). "BBC fail – my correct name is not permitted". blog.siliconglen.com. Retrieved 24 February 2011. 
  23. ^ Moore, Matthew (2 September 2008). "The Clbuttic Mistake: When obscenity filters go wrong". The Daily Telegraph (London). Retrieved 4 April 2010. 
  24. ^ "F-Word Town's Name Gets Censored By Internet Filter". Retrieved 27 July 2011. 
  25. ^ "Evaluating Head Injuries and Helmet Laws in Australia and New Zealand". 
  26. ^ Cameron, M; Cameron, M., Vulcan, A., Finch, C, and Newstead, S (June 1994). "Mandatory bicycle helmet use following a decade of helmet promotion in Victoria, Australia—an evaluation". Accident Analysis and Prevention 26 (3): 325–327. doi:10.1016/0001-4575(94)90006-X. PMID 8011045. 
  27. ^ "Evaluating the Health Benefit of Mandatory Bicycle Helmet Laws, Piet De Jong, Macquarie University – Actuarial Studies, 26 October 2009". Papers.ssrn.com. SSRN 1368064. 
  28. ^ Juan Forero, "Colombia's Coca Survives U.S. plan to uproot it", The New York Times, August 19, 2006
  29. ^ Don Podesta and Douglas Farah, "Drug Policy in Andes Called Failure," Washington Post, March 27, 1993
  30. ^ Dominic Streatfeild (June 2000). "Source Material for Cocaine: An Unauthorized Biography: Interview between Milton Friedman and Dominic Streatfeild". Dominicstratfeild. Retrieved 2012-11-21. 
  31. ^ "An open letter". Prohibition Costs. Retrieved 2008-02-20. 
  32. ^ *Huesemann, Michael H., and Joyce A. Huesemann (2011).Technofix: Why Technology Won’t Save Us or the Environment, Chapter 1, “The Inherent Unavoidability and Unpredictability of Unintended Consequences”, and Chapter 2, "Some Unintended Consequences of Modern Technology," New Society Publishers, Gabriola Island, British Columbia, Canada, ISBN 0865717044, 464 pp.
  33. ^ Bin Laden comes home to roost at the Wayback Machine (archived December 2, 1998)
  34. ^ "Blowback - 96.05". Theatlantic.com. Retrieved 2012-11-21. 
  35. ^ Peter Beaumont, foreign affairs editor. "Why 'blowback' is the hidden danger of war | World news". The Observer. Retrieved 2012-11-21. 
  36. ^ "The State Barrier Fence of Western Australia". The State Barrier Fence Project. Retrieved 2009-10-09. 
  37. ^ "Rabbits: Introduction into New Zealand". Christchurch City Libraries. Retrieved 2009-10-09. 
  38. ^ Smithsonian MagazineKudzu: Love It or Run
  39. ^ Molly McElroy (2005). "Fast-growing kudzu making inroads in Illinois, authorities warn". News Bureau, University of Illinois at Urbana-Champaign. Retrieved April 28, 2008. 
  40. ^ Richard J. Blaustein (2001). "Kudzu's invasion into Southern United States life and culture" (PDF). United States Department of Agriculture. Retrieved August 20, 2007. 
  41. ^ The perils of the Streisand Effect BBC News magazine 31 July 2014
  42. ^ Tentative ruling, page 6, stating, "Image 3850 was download six times, twice to the Internet address of counsel for plaintiff". In addition, two prints of the picture were ordered — one by Streisand's counsel and one by Streisand's neighbor. http://www.californiacoastline.org/streisand/slapp-ruling-tentative.pdf
  43. ^ Rogers, Paul (2003-06-24). "Photo of Streisand home becomes an Internet hit". San Jose Mercury News, mirrored at californiacoastline.org. Retrieved 2007-06-15. 
  44. ^ Canton, David. "Today's Business Law: Attempt to suppress can backfire", London Free Press, November 5, 2005. Retrieved July 21, 2007. The "Streisand effect" is what happens when someone tries to suppress something and the opposite occurs. The act of suppressing it raises the profile, making it much more well known than it ever would have been".
  45. ^ "Etheromaniac". World Wide Words. 2006-09-09. Retrieved 2012-11-21. 
  46. ^ "Our innate ability to think of new ways to use energy" Professor Tadj Oreszczyn. Summer 2009 edition of ‘palette’, UCL’s journal of sustainable cities.
  47. ^ Andres, Von Brandt (1984) Fish catching methods of the world ISBN 978-0-685-63409-7.
  48. ^ Likens, G. E., R. F. Wright, J. N. Galloway and T. J. Butler. 1979. Acid rain. Sci. Amer. 241(4):43–51.
  49. ^ Likens, G. E. 1984. Acid rain: the smokestack is the “smoking gun.” Garden 8(4):12-18.
  50. ^ Joyce, Christopher. "How The Smokey Bear Effect Led To Raging Wildfires". npr.org. Retrieved 27 August 2012.