November 22nd marks the 50th anniversary of the assassination of President John F. Kennedy. Over the years, numerous investigations have amassed evidence that Lee Harvey Oswald was the assassin, and failed to find compelling proof that anyone else was involved. Yet the identity of the person who fired the fatal bullet is still a subject of debate among the public. In the run up to the anniversary, the internet has been rife with conspiracy theories surrounding Kennedy’s death. Polls consistently show that conspiracist accounts of the JFK assassination are more widely believed than any other conspiracy theory – most surveys show that a majority of the US public suspects that Lee Harvey Oswald wasn’t acting alone. Why is it that this event, more than any other, captured the conspiracist imagination and refuses to let go?
Evidence in favour of a conspiracy is a mixed bag, at best. Conspiracy theorists have accused dozens of individuals and organisations of being involved in an assassination plot, but a conspiracy has never been definitively proven. Yet there are enough ambiguities and apparent inconsistencies in what is disparagingly termed the ‘official story’ to allow conspiracist narratives to thrive on the periphery of genuine scholarship. This year alone, a handful of new books claim to reveal startling new evidence substantiating various conspiracy theories.
Regardless of what actually happened that day, research suggests that we might be psychologically predisposed to see conspiracies behind events like the Kennedy assassination. This is because of an unconscious mental rule of thumb called the proportionality bias. When the outcome of an event is significant, proportionally significant causes seem more plausible. When consequences are modest, more modest attributions are made. Psychologists have demonstrated the bias using a variety of experimental scenarios, from reports of disease outbreaks and tornadoes to plane crashes and crimes. The findings are consistent: we tend to infer big causes for extreme events and small causes for insignificant events.
Few events are more momentous than the assassination of a nation’s leader. Explaining the death of President John F. Kennedy as the result of a lone, otherwise unremarkable individual violates the principle of proportionality. On the other hand, a theory alleging a vast, insidious conspiracy among a shadowy group of powerful figures might satisfy our unconscious desire for proportionality between cause and effect.
This idea was first put to the test in 1979, when researchers in the US created fake news stories reporting that the President of an unidentified nation had been shot at by an assassin. In one version of the story, the President was reported to have been fatally wounded. According to an alternative version of the story, however, the assassin’s bullet missed and the President escaped unscathed. People who read these scenarios were more likely to attribute the successful assassination to a conspiracy, while the unsuccessful assassination attempt was seen as the work of a lone gunman.
Three decades later, researchers in the UK repeated the experiment, finding the same pattern. But this time the researchers added two more scenarios. In one, the President was wounded by an assassin’s bullet, but miraculously survived. In another, the assassin’s bullet missed, yet shortly after the assassination attempt the President died of unrelated causes. In these new scenarios, the authors argued, the President’s fate is unrelated to the assassin’s skill or motives. Yet despite breaking the causal relationship between assassin and outcome, the proportionality bias still influenced people’s beliefs about the assassin. When the outcome was large in magnitude (the President died), the would-be assassin was judged likely to have been part of a conspiracy – even though he hadn’t caused the President’s death. When the outcome was minor (the President survived), the assassin was more likely to be viewed as a lone gunman.
Most recently, researchers in the US crafted assassination scenarios in which the causal chain between assassin and outcome was even more far removed. Fake news reports were again created for the research, this time claiming that a British newspaper had criticised the recently assassinated President of an unnamed country, thereby inciting terrorist attacks against Britain. One version of the story had dire consequences, reporting that Britain had declared war against the country as a result of the attacks. In a second version, the consequences were minor: the British Prime Minister responded peacefully, thereby subduing the attacks. Thus, the consequences of the assassination were arbitrarily determined by the British Prime Minister’s reaction. Despite the absence of a direct causal link between the initial assassination and its ultimate consequences, people preferred a conspiratorial explanation for the assassination when the magnitude of the consequences was large.
One more experiment by the same researchers ditched the pretence of fictional Presidents, and instead explicitly concerned the assassination of JFK. People who took part in the study were told either that Kennedy’s death had prolonged the Vietnam war, resulting in thousands of additional casualties, or that the assassination had no effect on the war. As expected, when the consequences were said to have been more significant, people endorsed a conspiratorial explanation of Kennedy’s assassination more strongly. When people were told that the assassination had not affected the war, however, they were slightly less likely to accept the conspiracy theory – though it was still preferred by over half of the participants.
These experimental findings offer a potential explanation for the continued popularity of conspiracy theories about JFK’s assassination. The event was so profound that the lone gunman account will always be unsatisfying. Conspiracy theories offer an explanation more intuitively befitting of such an extraordinary event. If the bullets had missed and Kennedy survived, conspiracy theories probably wouldn’t have gotten off the ground. Compare the assassination of JFK with the failed assassination attempt on President Ronald Reagan. Few people doubt that John Hinckley Jr. was acting alone when he tried to kill Reagan, yet people who believe Lee Harvey Oswald was a lone gunman are in the minority.
In reality, small causes can have large effects. Tiny pathogens cause pandemic disease outbreaks, one malfunctioning component can bring down an entire airplane, and a lone gunman can change the course of history. But these facts don’t fit with our intuitions. Instead, the proportionality bias imbues conspiracy theories with intuitive appeal which the ‘official’ explanations often lack. In this sense, conspiracism isn’t the result of a psychological defect or anomaly, but a byproduct of how our minds work normally. We’re all intuitive conspiracy theorists.