Mind Hacks highlighted an interesting article on the psychology (and sociology) of conspiracy theories which is available on-line through The Psychologist (alt: PDF, MP3). Some excerpts:
(…) Hofstadter’s essay on the ‘paranoid style’, in which he examined right-wing conspiracy theories, effectively set the tone of much of the research that was to follow. The paranoid style, Hofstadter argued, was a result of ‘uncommonly angry minds’, whose judgement was somehow ‘distorted’. Following this vein, some scholars came to view conspiracy theories as a product of psychopathology, such as extreme paranoia, delusional ideation or narcissism. In this view, the incorrectness of conspiracy theories was usually assumed a priori and, more than this, the delusional aspect of conspiratorial beliefs was thought to result in an incapacity for social or political action.
While it is possible that some people who believe in conspiracy theories suffer forms of psychopathology, this in itself is an incomplete explanation given how widespread conspiracy theories are. Hofstadter, however, has remained influential for his interest in why people acquire conspiracy theories, suggesting that a belief in conspiracy theories was more likely to emerge among those who felt powerless, disadvantaged or voiceless, especially in the face of catastrophe. To use a contemporary example, believing that the 7/7 London bombings were perpetrated by the British or Israeli governments may be, for some individuals at least, a means of making sense of turbulent social or political phenomena.
To the extent that conspiracy theories fill a need for certainty, it is thought they may gain more widespread acceptance in instances when establishment or mainstream explanations contain erroneous information, discrepancies, or ambiguities. A conspiracy theory, in this sense, helps explain those ambiguities and ‘provides a convenient alternative to living with uncertainty’. Or as Young and colleagues have put it, ‘[T]he human desire for explanations of all natural phenomena – a drive that spurs inquiry on many levels – aids the conspiracist in the quest for public acceptance.’
In addition, it is also thought that conspiracy theories offer explanations of the world that are not contradicted by information available to adherents. In the context of extremism, Hardin has discussed what he calls a ‘crippled epistemology’: in some cases, extremism is not an irrational response, but rather stems from the fact that people have very little correct or accurate information. Sunstein and Vermeule apply a similar perspective to conspiracy theories: those who believe in conspiracy theories may be responding rationally and logically to what little information they receive, even if that information appears absurd in relation to wider, publicly available knowledge.(…)
The last paragraphs of the excerpt also seem to point in the direction of what in some cases appears to be functions of the ultimate and lasting conspiracy theories better known as religions.
Also see several updates (via related links) at the end of this post.