The July 11 New Scientist, says we believe more in conspiracy theories when we have less wealth and power, when the questioned event happened in our early adulthood, and when the event had greater consequences:
A survey in 1968 found that about two-thirds of Americans believed the [JFK] conspiracy theory, while by 1990 that proportion had risen to nine-tenths. … Over 20 per cent of African Americans believe that HIV was created in a laboratory and disseminated by the US government in order to restrict the growth of the black population, … The people who believe this theory also tend to be more sceptical of government health messages that condoms can stop HIV transmission. … People who believe in one [conspiracy] theory are more likely to believe in others. …
Beliefs in JFK conspiracies are highest among people aged 36 and over, while those between 20 and 35 are most likely to see a conspiracy behind the 9/11 attacks. Surprisingly, perhaps, the youngest age group – 19 and under – are least likely to endorse any theory. … Ethnic minorities – particularly African and Hispanic … are far more believing of conspiracy theories … People who describe themselves as "hard up" are more likely to believe in conspiracies than those with average income levels, while the least likely to believe are the well off. …
I gave volunteers variations of a newspaper story describing an assassination attempt on a fictitious president. Those who were given the version where the president died were significantly more likely to attribute the event to a conspiracy than those who read the one where the president survived, even though all other aspects of the story were equivalent.
Of course none of this says whether we are on average too eager or too reluctant to believe in conspiracy theories. I just watched Platoon again, where army grunts say:
Politics, man, politics. We always getting fucked around here.
I’d love to see studies of such workplace conspiracy theories, to see who tends to believe in what illicit workplace influences, and how often they are right.