You're actually conflating two quite different societal constructs. Yes, there is undoubtedly a popular cultural stereotype of the conspiracy theorist as the uneducated, irrational “tin-foil-hat” type. Cartoons, films and popular culture have reinforced that image for decades. But that is a stereotype, not the definition of conspiracy theorist, and certainly not a scientific assessment of someone's intelligence. In fact, the psychological research is rather more nuanced than the caricature you are describing. There are studies and meta-analyses finding a modest statistical association between lower cognitive ability and greater endorsement of conspiracy beliefs. But correlation is not classification, and it certainly doesn't mean that conspiracy theorists are unintelligent. Intelligence is only one variable, and researchers repeatedly distinguish cognitive ability from cognitive style. And that distinction is important. A highly intelligent person can still reason badly. Intelligence gives you greater cognitive horsepower; it doesn't necessarily tell you where you're driving. Someone who is already committed to a conclusion can use considerable intelligence to construct increasingly elaborate justifications for it. That's motivated reasoning, not stupidity. Indeed, there is another rather amusing societal construct operating in the opposite direction. The conspiracy subculture often portrays the conspiracy theorist as the intelligent one. The believer is the person who has “done their own research”, “asked questions”, “woken up” and “seen through the lies”. Everyone else is a sheep, brainwashed by the mainstream media and incapable of thinking independently. So we have two competing caricatures: Mainstream stereotype: “Tin-foil-hat idiot who believes anything.” Conspiracy-subculture stereotype: “Independent genius who sees what everyone else is too stupid or brainwashed to see.” Neither is a useful way of assessing intelligence. The interesting question isn't “How intelligent is this person?” It's “How good is the reasoning being used to arrive at this particular conclusion?” Does the person distinguish evidence from speculation? Do they consider alternative explanations? Can their hypothesis actually be falsified? Do they change their position when evidence contradicts it? Do they apply the same evidential standards to claims they like as to claims they dislike? That's where the real issue lies. There is a particularly revealing irony here. Someone can complain that society unfairly portrays conspiracy theorists as unintelligent while simultaneously portraying themselves as intellectually superior to everyone who disagrees with them. “They think we're stupid; we know we're the ones who are awake.” That's not evidence of superior intelligence. It's simply another social construct. So yes, the “stupid conspiracy theorist” stereotype exists. But so does the “enlightened conspiracy theorist” stereotype. Neither tells us whether an individual argument is true. Intelligence isn't an epistemic trump card. Evidence is.
