Conspiracy theories

Is covid-19 caused by the 5G phone network, or the product of a secret Chinese bioweapons program? No. There is no evidence that either of these claims are true, but to some people that very lack of evidence is itself clear evidence of a cover up. Welcome to the paranoid, topsy-turvy world of the conspiracy theory.

Think of any major world event and there is almost certainly at least one conspiracy theory to explain it. The list is almost endless: the Apollo moon landings were faked, 9/11 was an inside job, climate change is a hoax, JFK was assassinated by the CIA, the earth is flat, the pharmaceutical industry is suppressing a cure for cancer, vaccines cause autism, Princess Diana was murdered by the royal family, Barak Obama was born in Kenya and is secretly a Muslim, the world is ruled by lizards. Many of these “theories” – the word is used in its colloquial sense rather than the strict scientific one, they should really be called “conspiracy hypotheses” – concern matters of science or medicine.

It is easy to dismiss conspiracy theories as unhinged beliefs held by a small number of paranoid idiots, but that seriously underestimates them. Belief in conspiracy theories is very widespread, the product of normal human psychology, and extremely influential and dangerous.

About half of Americans believe in one or more of the common ones. Belief is more widespread among the less-educated, but is by no means confined to them. Educated people are also susceptible if a conspiracy theory fits with their pre-existing world view.

The theories are also endorsed across the ideological spectrum. They are literally left, right and centre. More conservatives than liberals believe the Obama “birther” theory – promulgated by Donald Trump – but many liberals believe 9/11 was a government plot to drum up support for invading Iraq.

Why do so many people believe? One reason, say psychologists, is that it is perfectly reasonable, because conspiracies sometimes happen. Consider the Iran-Contra affair in the 1980s, when senior US officials conspired to sell weapons to Iran – then under an arms embargo – and channel the proceeds to rebels trying to oust Nicaragua’s socialist government.

Conspiracy theories also reflect how we intuitively understand the world and events in it. The human brain did not evolve to process complex information about global politics, economics or science. It evolved to survive on the African savannah where threats and hostile intentions were a daily reality.

Under these circumstances it pays to assume that unseen threats are lurking everywhere, that “outgroups” have malign intent, or that coincidental events are causally related. The cost of holding these assumptions was minimal, but the cost of not holding them was often death. Natural selection favoured the conspiratorial mindset.

Our brains have other cognitive biases that make us susceptible to conspiracy theories. One is proportionality bias, a belief that major events have major causes. Intentionality bias makes us assume that events are planned by somebody or something. Confirmation bias means we seek out evidence that supports our beliefs. And the illusion-of-understanding bias makes us overestimate our knowledge of how things work.

Conspiracy theories can also paradoxically be emotionally reassuring. They provide truthful-sounding explanations for events that otherwise seem inexplicable, random or capricious, and often make your political opponents look bad. They can also give believers a pleasing sense of superiority because they – and sometimes they alone – have seen through the lies and cover-ups to reveal the “truth”.

Personality type also plays a part. People who are naturally suspicious of received wisdom and authority are more likely to believe.

Conspiracy theories are often utterly preposterous and totally lacking in credible evidence, but they are almost impossible to disprove, at least in the minds of believers. No amount of counter-evidence can refute them, and in fact this evidence often reinforces them because it can be dismissed as part of the conspiracy.

In this respect conspiracy theories have much in common with pseudoscience, which superficially resembles science but lacks its crucial epistemological feature, falsifiability – meaning that hypotheses must be structured such that they can be disproved by new evidence.

The conspiratorial mindset may have been an asset in the past, but is now a liability. When it comes to dealing with important issues such as climate change or the cause of covid-19, conspiracy theories are a major obstacle to reasoned debate and evidence-based action.