What Makes Intelligent People Believe Things That Aren't True?

Why intelligence doesn't guarantee good judgment, and how convincing stories can overpower evidence.

Intelligent people believe things that aren't true because intelligence is only one part of how we form beliefs. Our judgments are also shaped by what we want to be true, whom we trust, what other people believe, and how much we have invested in our existing convictions. Intelligence helps us evaluate evidence, but it doesn't guarantee that we'll examine the right evidence or recognize when our reasoning has become self-serving.

Sometimes, the better we are at constructing arguments, the easier it becomes to defend a conclusion we should be questioning.

The Elizabeth Holmes Problem

In 2018, the Securities and Exchange Commission charged Elizabeth Holmes and her company, Theranos, with an elaborate fraud involving more than $700 million raised from investors.

Holmes promised technology capable of performing extensive blood testing using just a few drops of blood. The prospect was extraordinary: cheaper testing, earlier diagnosis, and a transformation of modern medicine.

Prominent investors, business leaders, and political figures embraced the company. Yet according to the SEC's findings, Theranos's proprietary equipment could perform only a small number of tests, and the company relied heavily on conventional laboratory machines. Holmes was convicted of investor fraud in January 2022.

How did so many accomplished people believe in something that wasn't working?

Holmes presented a vision that fit Silicon Valley's celebration of founders who challenge established industries. Her supporters recognized the enormous potential of the idea without verifying that the technology worked.

Their intelligence allowed them to evaluate the business opportunity and construct persuasive arguments for its potential, but those abilities did not establish whether the underlying science was sound.

The more credible people associated themselves with Theranos, the more credible the company appeared. But an investor's reputation is not evidence that a blood-testing machine functions.

The scandal illustrates a broader problem. People can become convinced by the surrounding evidence of success while overlooking the evidence needed to establish whether the central claim is true.

When Reasoning Protects What We Already Believe

Psychologists call one mechanism motivated reasoning: evaluating information in ways influenced by a preferred conclusion.

In a 2017 study published in Behavioural Public Policy, researchers including Dan Kahan examined how people interpreted numerical evidence.

Participants evaluated data presented as either the results of a treatment for skin rashes or the effects of a gun-control policy.

When examining the skin treatment, people with stronger numerical reasoning skills generally performed better. When the same kind of problem involved gun control, political differences influenced interpretation. Those differences became larger, not smaller, among the most numerically skilled participants.

In this experiment, stronger analytical ability was associated with greater political polarization in interpreting evidence.

This doesn't mean intelligent people are generally more vulnerable to misinformation. Numeracy is not the same as intelligence, and the result concerned a specific politically charged task. But it demonstrates that reasoning ability and the willingness to reach an unwelcome conclusion are different things.

We can use intelligence to discover whether something is true or to defend something we've already decided to believe.

Why Repetition Can Feel Like Evidence

Another mechanism is the illusory truth effect, the tendency for repeated statements to seem more believable because they become familiar.

In a 2015 study, psychologist Lisa Fazio and colleagues investigated whether prior knowledge protected people against this effect. Surprisingly, participants sometimes rated repeated false statements as more truthful even when they possessed the knowledge needed to recognize those statements as false.

Familiarity makes information easier to process, and that ease can be mistaken for credibility.

Imagine hearing a claim from a colleague, encountering it in an article, and seeing it repeated on social media. The claim begins to feel established, even if every version traces back to the same unsupported source.

What feels like three pieces of evidence may be one assertion repeated three times.

Why We Trust People Who Appear to Know More

Most of what we believe comes from other people. We cannot independently verify every medical finding, engineering principle, or economic statistic. Relying on expertise is essential to functioning in a complex world.

The problem arises when we confuse expertise in one domain with authority in another.

A successful investor may understand markets without understanding medical diagnostics. An accomplished executive may recognize an extraordinary business opportunity without knowing whether the underlying science is sound.

Social influence compounds the problem. In Solomon Asch's conformity experiments, participants sometimes repeated obviously incorrect answers after hearing a group give those answers. Real-world judgments are far more ambiguous than comparing the lengths of lines.

When respected colleagues agree, challenging their conclusion can feel like questioning their competence. Their apparent consensus becomes a substitute for independent verification.

Does Intelligence Still Protect Us?

Yes, and this distinction matters.

A 2019 study by Gordon Pennycook and David Rand, involving 3,446 participants, found that people who performed better on a cognitive reflection test were generally better at distinguishing real from false news headlines. Analytical thinking helped even when headlines aligned with participants' political beliefs.

Intelligence and reflective thinking are valuable protections against misinformation. The research does not support a blanket claim that smarter people are more susceptible to falsehoods.

But ability doesn't eliminate self-deception.

In a separate 2012 study, Richard West, Russell Meserve, and Keith Stanovich examined the bias blind spot, our tendency to recognize biases in other people more readily than in ourselves. Greater cognitive sophistication did not eliminate this tendency.

Together, these findings reveal an important distinction: being better at reasoning does not guarantee that we recognize when our own reasoning is compromised.

What Would Actually Prove It?

Consider Theranos again. Independent validation of its blood-testing technology would have addressed the central claim. An impressive board of directors, a rising valuation, and an inspiring founder could not.

The same distinction applies whenever we encounter an extraordinary claim.

Something can be proven, supported by reliable evidence. It can be plausible, consistent with what we know but not yet demonstrated. Or it can be hoped for, a future possibility that inspires enthusiasm without establishing present reality.

All three have legitimate places in how we think about innovation, science, and progress. Problems arise when we confuse them.

The practical challenge is not to distrust everyone or reject ambitious ideas. It is to identify which claims have been demonstrated, which remain untested, and which depend on something we simply want to be true.

That distinction becomes especially important when we find ourselves defending a belief rather than investigating it.

🧬 QuestionStrings to Practice: Testing Conviction

Use this sequence when a claim feels especially convincing.

What exactly am I convinced is true? → What evidence originally convinced me? → How much of that evidence is independent? → What evidence would cause me to reconsider? → Am I willing to seek it?

The purpose isn't to eliminate conviction. It's to understand what supports it.

The most dangerous false beliefs are not always those we accept without thinking. Sometimes they are the ones we have spent the most time learning how to defend.

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