I Believe, So . . . There

The Flat Earth Society was founded in Victorian England to preach one simple belief: Our planet is not a sphere. This was not a metaphor. Followers believed, quite literally, that we all inhabit a large disc, with the North Pole at the center and a large wall of ice at its edge. This particular brand of magical thinking pretty much died out in the early 20th century, though a few hangers-on were still around to accuse NASA of fraud when the agency published photographs that clearly showed a blue orb spinning in space.

The last Flat Earther supposedly was spotted in California, near Los Angeles, some years ago. But the term endures in our cultural idiom, where it has come to mean any dogmatic, rigidly anti-scientific thinker: Creationists, holocaust-deniers, indeed anyone who insists on an irrational belief, all meaningful evidence to the contrary notwithstanding. The label also suggests an in-your-face, mean-spirited kind of stupidity.

Are we being too hard on Flat Earthers? Let’s look at the evidence. Psychologists have long been interested in why we make so many errors in logical reasoning and judgment. Why are we superstitious, for example? These scientists have been studying the human mind’s complex reasoning process, and there is today broad agreement on one fundamental idea: We have two very different cognitive machines working at the same time. One is a rapid, automatic, belief-driven machine, and the other is a slow and deliberate analytical machine.

When these dual processors are working in concert, all is well. The logic supports the belief. That’s why we’re not in mental anguish over widely-shared wisdom—the existence of subatomic articles, for example, or the structure of DNA. But what happens when our two mental processes don’t jibe? Psychologist Wim De Neys of the University of Leuven, Belgium, decided to explore this experimentally, to see how belief and logic slug it out in the mind. He also wanted to know if this cognitive interplay is different in smart and stupid people.

Since nobody really believes in a flat Earth anymore, De Neys had to find another way to study faulty reasoning in the lab. So he used syllogisms. He first sorted volunteers using a standard test of mental acumen, then had all of them work through a series of syllogisms. Some were logically valid, while others were not, and the volunteers had to determine which were which. Here’s one:

All fruits can be eaten.
Hamburgers can be eaten.
Therefore, hamburgers are fruits.

This one is easy, because not only is the conclusion ridiculous, the logic is obviously flawed as well. Even the stupid volunteers got this right immediately. But how about this one?

All mammals can walk.
Whales are mammals.
Therefore, whales can walk.

Again, the conclusion is wildly impossible, but to understand why requires some mental gymnastics. The syllogism is logical, but you have to stop and analyze a bit to realize that the false conclusion follows from a false premise—that is, that all mammals can walk. As De Neys reports in the journal Psychological Science, many people get this wrong: They fail to see the logic when the conclusion is so absurd.

But why? Here's where the volunteers' mental ability comes into play. De Neys added another mental task to the syllogism test, this one designed only to tax the volunteers’ overall mental resources. He found that the added mental demands were much harder on the slower problem solvers, causing them to default to their less rational belief system more readily. In other words, they lacked the cognitive capacity to rigorously reason themselves out of a wrong-headed conclusion.

So back to the original question: Are we being too hard on the Flat Earthers? Maybe, in a sense. Another analysis by De Neys showed that the slower subjects were not coming to their false conclusions because they didn’t try. They did indeed try to use their analytical skills, but their analytical skills were limited, so they failed. And the stupider they were, the more likely they were to fail—and to fall back on illogical beliefs. So creationists and holocaust deniers and other modern-day Flat Earthers may not be hateful after all. It may be that they really, really can’t think any better than that.

For more insights into human nature, visit the Association for Psychological Science website at www.psychologicalscience.org.