Think You’re an Expert? That May Hurt You

Imagine you’re asked to attend a presentation about how to use Microsoft Excel in the workplace. This feels like a waste of time considering that you’ve been using the program for years. But at the workshop, you unexpectedly learn something new: With a few simple lines of code, you can have Excel automatically collect information to compose and send an email, saving you an hour a week of work. It turns out that you have more to learn after all.

There’s a difference between what people think they know and what they actually know, and this shapes our decisions, finds research by Chicago Booth PhD student Samuel Borislow and Booth’s Daniel Bartels. According to their study, overconfidence may cause us to overlook details that could improve our decisions, while being open to the possibility of learning more pushes us toward deeper, more complex comparisons.

In a set of five studies, the researchers observed how people use different types of information when assessing common products such as cars, chocolate, laundry detergent, toothbrushes, and wine.

In one of the studies, 390 participants who were recruited online first rated how knowledgeable they felt about the products, which provided a measure of subjective expertise. They then took quizzes designed to gauge what they actually knew, or their objective expertise, about the products.

The quizzes revealed that the participants’ self-confidence and objective expertise were only moderately related. Some who felt they were highly knowledgeable about a car or detergent didn’t score well on a test about it, while others who scored well didn’t rate themselves as particularly knowledgeable.

This mismatch set the stage for a different study in which researchers asked 335 online participants to choose between two cars or wines via a survey. Each participant was asked to choose two additional “custom” features they wanted to consider when making their decision and had a choice between “alignable” features (easy to compare from product to product) or “nonalignable” features. For wine, alignable attributes included price, region, and grape variety. A nonalignable attribute, such as tasting notes or aroma, would require more knowledge to interpret.

Participants with objective expertise used nonalignable attributes more often—they appeared comfortable evaluating unique or complex features of the products and factoring them into their choices. But participants with a higher level of subjective expertise leaned more heavily on alignable attributes. Confidence doesn’t necessarily lead to more sophisticated decision-making but may instead lead to simpler comparisons, the researchers write.

In other studies, participants with high subjective expertise were also less likely to take advice or seek out additional information before making their choice.

The fact that confidence is not the same as competence has clear implications for marketers. Advertisements that emphasize simple, comparable metrics—such as price, speed, or size—can be effective at reaching consumers who believe they already understand a product.

Beyond that, if confidence discourages people from seeking additional information or advice, it may lead them to overlook details that could improve their decisions, whether they’re choosing between investment options or medical treatments.

But the study offers a hopeful takeaway: Genuine knowledge appears to encourage deeper thinking and broader information use. People who truly understand a topic engage more fully with the complexity of their choices.