Jamie Bartlett is head of the Violence and Extremism Program at Demos, a research group based in London.

When Americans visit the Middle East or the broader Islamic world, they are often struck by the vitality of public interest and discussion about world affairs. Less comfortably, they often find the public to be cynical about Western interests, and quick to believe that shadowy groups control the world: that a cabal of Jews was responsible for 9/11 or that the C.I.A. instigated the Arab Spring for oil access.

This is not a stereotype, but a fact of Middle Eastern cultures – and a fact that Western nations must reckon with. Conspiracy theories of this type are ubiquitous in the region; 75 percent of Egyptian Muslims do not believe Arabs were behind 9/11, with many faulting the U.S. government or Jews instead.

Citizens justify sacking an embassy because they believe the U.S. to be part of a network of manipulation and evil machination. Who can change that?

Perhaps citizens of the Islamic world have good reason to be skeptical, having long been lied to by their own governments. Commentators in the region often propound these stories. And the West has not helped: the installation of the shah and the Suez Canal are part of the collective memory.

Conspiracy theories are highly corrosive, because they represent the most radical form of distrust in government possible. Public trust in governing institutions is essential in healthy democratic society and vital for diplomatic efforts. Skepticism is usual and healthy, but conspiracy theories inspire a generalized, knee-jerk cynical mistrust – and keep a populace primed for panic and violence against the West. (The power of conspiracy theories is global, f course: One interesting study found that after watching Oliver Stone's 1991 film “JFK,” which alleges that the assassination of President John F. Kennedy was a conspiracy, moviegoers in the U.S. said they were less likely to vote and make political contributions.)

Our work suggests that conspiracy theories are often part of radical or violent ideologies, serving to delegitimize enemies. It is more justifiable to sack an embassy when you believe it to be part of a network of manipulation and evil machination.

Not every problem has a solution, and dealing with conspiracy theories is especially tricky – especially in an era when misinformation is ubiquitous online and spreads faster than ever before. Western governments will get nowhere by trying to rebut misinformation. Openness and transparency are good, although not enough (and not always possible).

Good relationships between citizens and communities across borders might be more promising. The Somali community in the U.S., or the Pakistani one in the U.K., could help to build confidence “back home” about the reality of living in liberal democracies. This is the long, hard road of gaining trust on the ground, drawing on networks of people rather than government-led information campaigns. But it won’t happen overnight.