According to the Merriam-Webster online dictionary, to "debunk" is defined as: "to expose the sham or falseness of."
If debunkers are not careful, their communications may backfire - increasing an audience's long-term belief in myths. Backfire effects can occur if a message spends too much time on the negative case, if it is too complex, or if the message is threatening.
The term "debunk" originated in a 1923 novel Bunk, by American journalist and popular historian William Woodward (1874-1950), who used it to mean to "take the bunk out of things".
The term "debunkery" is not limited to arguments about scientific validity; it is also used in a more general sense at attempts to discredit any opposing point of view, such as that of a political opponent.
Alan Melikdjanian (Captain Disillusion) is a debunker of viral videos and hoaxes on the Internet, usually deconstructing them and explaining the post production techniques and software used to create the illusions.
Donald Menzel was Philip Klass's predecessor in debunking UFOs.
Phil Plait is an astronomer and science writer whose speciality is fighting pseudoscience related to space and astronomy. He established Badastronomy.com to counter public misconceptions about astronomy and space science, providing critical analysis of pseudoscientific theories related to these subjects.
Benjamin Radford is an American writer, investigator, and skeptic who has authored, coauthored or contributed to over twenty books and written over a thousand articles and columns debunking topics such as urban legends, unexplained mysteries and the paranormal.
Phil Mason is a scientist and YouTuber with the online pseudonym "Thunderf00t" (also "VoiceofThunder"), who debunks various snake-oil merchants and fundraiser campaigns for certain products, using basic scientific understanding, e.g. the laws of thermodynamics, to show that the advertised things simply make no sense and cannot deliver what is promised. He is known for criticising religion, pseudoscience, creationism, Hyperloop, Solar Roadways, etc.
The authors of the Debunking Handbook warn that a failed debunking can actually worsen misconceptions. They recommend simple, positive, and emotionally sensitive education (e.g., bolstering the learner's ego, or avoiding threatening words).
Australian Professorial Fellow Stephan Lewandowsky and John Cook, Climate Communication Fellow for the Global Change Institute at the University of Queensland (and author at Skeptical Science) co-wrote Debunking Handbook, in which they warn that debunking efforts may backfire. Backfire effects occur when science communicators accidentally reinforce false beliefs by trying to correct them, a phenomenon known as belief perseverance.
Cook and Lewandowsky offer possible solutions to the backfire effects as described in different psychological studies. They recommend spending little or no time describing misconceptions because people cannot help but remember ideas that they have heard before. They write "Your goal is to increase people's familiarity with the facts." They recommend providing fewer and clearer arguments, considering that more people recall a message when it is simpler and easier to read. "Less is more" is especially important because scientific truths can get overwhelmingly detailed; pictures, graphs, and memorable tag lines all help keep things simple.
The authors write that debunkers should try to build up people's egos in some way before confronting false beliefs because it is difficult to consider ideas that threaten one's worldviews (i.e., threatening ideas cause cognitive dissonance). It is also advisable to avoid words with negative connotations. The authors describe studies which have shown that people abhor incomplete explanations - they write "In the absence of a better explanation, [people] opt for the wrong explanation". It is important to fill in conceptual gaps, and to explain the cause of the misconception in the first place. The authors believe these techniques can reduce the odds of a "backfire" - that an attempt to debunk bad science will increase the audience's belief in misconceptions.
The Debunking Handbook 2020 explains that "backfire effects occur only occasionally and the risk of occurrence is lower in most situations than once thought". The authors recommend to "not refrain from attempting to debunk or correct misinformation out of fear that doing so will backfire or increase beliefs in false information".
^Houdini and the spiritualists, Summit Daily News, November 3, 2007, "Houdini himself wouldn't have believed in his second coming anyway, because he didn't believe in spirit manifestations. In fact, he spent much of his life and career debunking spiritualists and mediums - an admirable mission that history and forensic specialists now tell us probably led to his untimely death at the age of 52."
^"Obituaries; Betty Hill, 85; Claim of Abduction by Aliens Led to Fame", Los Angeles Times, Oct 24, 2004, "Carl Sagan, the Pulitzer Prize-winning astronomer, was among the Hills' debunkers, yet he considered their story noteworthy."
^Beveridge, W. I. B. (1950). The Art of Scientific Investigation. New York: Norton. p. 106.
^Skurnik, I.; Yoon, C.; Park, D.; Schwarz, N. (2005). "How warnings about false claims become recommendations". Journal of Consumer Research. 31 (4): 713-724. doi:10.1086/426605.
^Weaver, K.; Garcia, S.M.; Schwarz, N.; Miller, D.T. (2007). "Inferring the popularity of an opinion from its familiarity: A repetitive voice sounds like a chorus". Journal of Personality and Social Psychology. 92 (5): 821-833. doi:10.1037/0022-3522.214.171.1241. PMID17484607.
^Schwarz, N.; Sanna, L.; Skurnik, I.; Yoon, C. (2007). Metacognitive experiences and the intricacies of setting people straight: Implications for debiasing and public information campaigns. Advances in Experimental Social Psychology. 39. pp. 127-161. doi:10.1016/S0065-2601(06)39003-X. ISBN9780120152391.