inFact with Brian Dunning inFact with Brian Dunning


Conspiracy Theories

Why do so many people believe in completely improbable conspiracy theories?

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Everywhere you turn these days, someone is promoting some wacky-sounding conspiracy theory. Everything from the old classics like the government shot John F. Kennedy and the government was in on 9/11, to the most far-out stories like Denver Airport is the secret headquarters of the Illuminati, and world leaders are actually reptilian aliens wearing electronic disguises. And we'll always have the popular favorites: the medical industry conspires to keep us all sick, the food industry conspires to make us all fat, and the oil companies conspire to suppress new clean energy technologies.

Conspiracy theories are so prevalent that I might have just made you mad by naming one you believe in.

Why do so many people believe in some of the craziest conspiracies? Are these people all suffering from a delusional disorder? No. Belief in conspiracy theories, no matter how ridiculous they are, doesn't mean someone is crazy. All it means is that they're human, and their brain is doing exactly the job it evolved to do.

The human brain evolved to keep itself alive to the best of its ability. Suppose something rustled in the tall grass. Some of our ancestors weren't too concerned, and figured it was merely the wind; but others were more cautious, suspected a panther, and jumped for the nearest tree. Over the eons, and hundreds of thousands of generations, the nonchalant ancestors were wrong (and got eaten) just often enough that eventually, most survivors were those who tended toward caution, and even paranoia. In evolution, it pays to err on the side of caution. The brains most likely to survive were those who saw a panther in every breath of wind, an angry god in every storm cloud, a malevolent purpose in every piece of random noise. We are alive today as a race, in part, because our brains piece random events together into a pattern that adds up to a threat that may or may not be real. As a result, we are afraid of the dark even though there's rarely a monster; thunder frightens us even though lightning is scarcely a credible threat; and we perceive the menace of evil conspiracies in everyday events.

The question we have to answer is can our intellect trump our animal instincts.

Now, before you comment on this video to tell me that some fringe conspiracy theory is actually true, hear what I have to say about it. Come to and search for it.

— Brian Dunning

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References & Further Reading

APA. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV-TR). Arlington: American Psychiatric Association, 2000. 323-329.

Coady, D. Conspiracy Theories: The Philosophical Debate. Hampshire: Ashgate Publishing, 2006.

Goertzel, T. "Belief in Conspiracy Theories." Political Psychology. 1 Dec. 1994, Volume 15, Number 4: 733-744.

Novella, S. "Hyperactive Agency Detection." NeuroLogica Blog. New England Skeptical Society, 22 Mar. 2010. Web. 26 Jun. 2011. <>

Shermer, M. The Believing Brain: How We Construct Beliefs and Reinforce Them as Truths. New York: Henry Holt and Company, 2011. 207-230.

Vedantam, S. "Born with the Desire to Know the Unknown." The Washington Post. 5 Jun. 2006, Newspaper: A05.


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