|Coined by||M. Lamar Keene (1976)|
|Definition||The condition of continuing to believe a paranormal event/phenomenon after it has been debunked|
|Signature||Belief continues without grounds or base|
True-believer syndrome is an informal or rhetorical term used by M. Lamar Keene in his 1976 book The Psychic Mafia. Keene used the term to refer to people who continued to believe in a paranormal event or phenomenon even after it had been proven to have been staged. Keene considered it to be a cognitive disorder, and regarded it as being a key factor in the success of many psychic mediums.
In his book The Psychic Mafia, Keene told of his partner, a psychic medium named "Raoul" in the book. Some in their congregation still believed that Raoul was genuine even after he openly admitted that he was a fake. Keene wrote "I knew how easy it was to make people believe a lie, but I didn't expect the same people, confronted with the lie, would choose it over the truth. ... No amount of logic can shatter a faith consciously based on a lie."
According to The Skeptic's Dictionary, an example of this syndrome is evidenced by an event in 1988 when James Randi, at the request of an Australian news program, coached stage performer José Alvarez to pretend he was channelling a two-thousand-year-old spirit named "Carlos". Even after it was revealed to be a fictional character created by Randi and Alvarez, many people continued to believe that "Carlos" was real. Randi commented: "no amount of evidence, no matter how good it is or how much there is of it, is ever going to convince the true believer to the contrary."
In the book When Prophecy Fails, Festinger and his colleagues observed a fringe group led by Marian Keech who believed that the world would be destroyed on December 21, 1954 and the true believers would be rescued by aliens on a spaceship to a fictional planet Clarion. When nothing happened, the group believed that their devotion convinced God to spare the world and they became even more feverish in proselytizing their belief. This is one of the first cases that led Festinger to form the theory of cognitive dissonance. 
In an article published in Skeptical Inquirer, psychologist Matthew J. Sharps and his colleagues analyze and dissect the psychology of True Believers and their behavior after the predicted apocalypse fails to happen. Using the 2012 Mayan apocalypse prophecy as example, and cited several other similar cases, Sharps contributes four psychological factors that compel these people to continue the belief (or even stronger belief) despite the conflicted reality. 
- Subclinical dissociative tendencies: While not suffered from mental illness, people with subclinical dissociative tendencies have a higher inclination to experience disconnection with immediate physical reality and propensity to see highly improbable things with enhanced credulity. Such subclinical dissociation is usually associated with paranormal thinking. 
- Cognitive dissonance: The more one invests in a belief, the more value one will place on this belief and in consequence, be more resistance to facts, evidence or reality that contradict with this belief. Some of the True Believers in the Keech case in example above had left their spouses, jobs and gave up their possessions to prepare to board the alien spacecraft. When the world did not end, cognitive dissonance provided an enhancement of their beliefs and outlet for their heavy investment and discomfort in front of reality. 
- Gestalt processing: In the continuum in human information processing, people with Gestalt processing will consider a concept without detailed analysis (as opposed to feature-intensive thinking) and accept the idea as a whole relatively uncritically. Sharps suggests a relationship between dissociative tendencies and gestalt processing. People who incline to believe paranormal activities will be more likely to credulously entertain the ancient Mayan prophecies whose details most people know little about. 
- Availability heuristic: Under the mental shortcut of availability heuristic, people place more importance and give more weight to a belief when examples related to the idea are more readily recalled, most often because they are recent information and latest news.  The information of Mayan prophecies has been abundantly available, especially in the media, before the expected apocalyptic date. People's judgments tend to bias toward this latest news, particularly those with dissociative tendency toward supernatural and favor gestalt processing. 
- Lamar, Keene, M. (1976). The Psychic Mafia. St. Martin's Press; New York
- Lamar and Sgragett, p.151
- Davis, W. Sumer. Just Smoke and Mirrors: Religion, Fear and Superstition in Our Modern World. pp. 11–12. ISBN 0-595-26523-5.
- "true believer syndrome". Skeptic's Dictionary. Retrieved 2007-08-19.
- Lamar and Spraggett, pp.141–151
- ABC News (1998-10-06) "The Power of Belief: How Our Beliefs Can Impact Our Minds", ABC News (2007-06-04)
- Festinger, Leon; Henry W. Riecken, Stanley Schachter (1956). When Prophecy Fails: A Social and Psychological Study of a Modern Group that Predicted the Destruction of the World. University of Minnesota Press. ISBN 1-59147-727-1.
- Sharps, Matthew; Liao, Schuyler; Herrera, Megan (2014). "Remembrance of Apocalypse Past". Skeptical Inquirer (CSI) 38 (6): 54–58.
- Tversky, Amos; Kahneman, Daniel (1973). "Availability: A heuristic for judging frequency and probability". Cognitive Psychology 5 (2): 207–232. doi:10.1016/0010-0285(73)90033-9. ISSN 0010-0285.
- Keene, M. Lamar and Spraggett, Allen (1997) The Psychic Mafia, Prometheus Books, ISBN 1-57392-161-0
- Hall, Harriet A., (2006). "Teaching Pigs to Sing: An Experiment in Bringing Critical Thinking to the Masses", Skeptical Inquirer, Vol 30, #3, May/June 2006, pp. 36–39
- Lalich, Janja. Bounded Choice: True Believers and Charismatic Cults. University of California Press, 2004. ISBN 0-520-23194-5
- Raymo, Chet. Skeptics and True Believers: The Exhilarating Connection Between Science and Religion. Walker Publishing, 1998. ISBN 0-8027-1338-6
- Singer, Barry and Benassi, Victor A., (1980). "Fooling Some of the People All of the Time", Skeptical Inquirer, Vol 5, #2, Winter 1980/81, pp. 17–24