When Maria Rodas and Jennifer Stoner met in graduate school at the University of Minnesota nearly a decade ago, one of the things that they bonded over was a shared love of chocolate.

“We both considered ourselves chocoholics,” said Rodas, now an assistant professor of business administration at Gies College of Business at the University of Illinois Urbana-Champaign. “And then we started mulling, like, ‘Does this make us connoisseurs of chocolate?’”

Around that time, Rodas was working on a study of people’s secret eating habits and decided to include a sample of chocolate that was billed as the world’s best. She no longer remembers the brand name, but she does recall that it was from Venezuela and cost $20 a bar. Naturally, she and Stoner had to try it.

They were not impressed. “It wasn’t worth the $20,” said Rodas. Maybe, they decided, they weren’t actually true connoisseurs because they were unable to appreciate the best chocolate in the world.

Then Rodas thought back to an experience before she became a doctoral student, when she was working as a brand manager at General Mills and had to administer blind taste tests of Yoplait yogurt to see how people reacted to changes in ingredients. The testers were all yogurt fans, but they couldn’t detect the differences between the various samples.

“I started thinking, maybe that's not the best way to go about it because the participants might be blind to these subtle differences without knowing which brand they were tasting,” Rodas said. Without knowing the brand, they couldn’t be certain if it tasted like Yoplait. As far as they were concerned, all yogurt was good yogurt.

Could it be possible that Rodas and Stoner’s love of chocolate had blinded them to subtleties in flavor in the same way?

For years, they considered this problem, even after Rodas began teaching at Gies and Stoner at the University of North Dakota Grand Forks. Now they have a solution, which they have published in a paper in Marketing Letters called “Love is blind: the ironic effect of fans’ experience on taste perception.” The paper is based on a series of taste-test experiments, each involving a nearly universally-beloved food: cheese, coffee, and, of course, chocolate.

In the first study, 129 participants tasted samples of sharp and mild cheddar cheese, first blindly and then after reading a description of a fictitious brand. After each tasting, they took a survey rating the sharpness of the cheese and their degree of cheese fandom. The researchers discovered that self-professed cheese fans rated the sharpness of the two cheeses as equal in the blind test, but were able to correctly distinguish between sharp and mild after reading the brand description.

For the second experiment, Rodas and Stoner recruited 205 undergrad students who had already spent an hour participating in another study. They asked the students if they would be willing to complete an additional survey in exchange for a bar of chocolate. The researchers assumed that those who agreed to spend more time on yet another survey, despite having already completed an hour of tasks, demonstrated a genuine love for chocolate. This recruitment method allowed them to focus on individuals likely to be true chocolate enthusiasts: previous research suggested that fans are often willing to go the extra mile for what they love. 

The researchers distributed bars of dark and milk chocolate to all the students. Both bars were from a German brand called Moser-Roth, but only some of them were labeled. After tasting, the students rated the intensity of the chocolate in each bar. As in the cheese experiment, the students with the unlabeled chocolate were unable to distinguish between the two bars, while the students with more information could tell the difference.

“We saw the effect, and we spent a lot of time trying to figure out what was going on,” Rodas said. “The adage that ‘love is blind’ came to mind, but we realized that the phenomenon we were observing was more nuanced.

“All human beings are cognitive misers,” Rodas continued. “If we had to pay attention to every single thing that came our way, we would be completely depleted by 10 AM. If you have that much experience eating chocolate, you don't have to go through this very cognitive depleting process of making sense of the experience. Your brain says, ‘I am going to rely on these past experiences,’ and that's what blinds you.”

When the cheese- and chocolate-lovers were eating the unlabeled products, their brains were taking a shortcut, relying on a lifetime’s worth of information about cheese and chocolate to draw conclusions about the taste instead of sorting through what was actually happening in the moment. This is known as top-down processing. 

But when those tasters were forced to reflect, even by something as simple as a label or brand description, their brains slowed down to take in specific details about the flavor of what they were eating. This is called bottom-up processing.

In a final experiment, Rodas and Stoner decided to encourage bottom-up processing. Participants were given either branded or unbranded cups of strong and weak coffee, or they were asked, before an unbranded tasting, to read a prompt that urged them to focus their attention on the sensory experience of drinking the coffee.

As in the previous experiments, the tasters filled out surveys rating their love of coffee and the strength of the coffee they’d just tasted. As before, the coffee fans with the brand information rated the strength of the coffee more accurately than those without. But so did the coffee fans who had only read the prompt.

“The entire project was incredibly rewarding to put together,” Rodas said. “Collaborating with Jen, one of my favorite collaborators, made the research even more enjoyable.” Rodas emphasized how companies could benefit from the insights they had gathered. "If I were still at General Mills, I would ensure that not all taste tests are conducted blindly. While blind tests are useful for certain types of feedback, they can obscure the nuanced ways in which brand context influences perception.” By incorporating both blind and branded tests, she explained, companies could get a fuller picture of how consumers perceive their products in real-world settings.

“What makes a lot of the work more meaningful for me is when I know that it has very clear implications for practitioners,” Rodas said. “I also think this is just generally interesting for people because many of us think of ourselves as chocoholics. The idea that our love for this product might be blinding us may seem counterintuitive at first, but when you explain why that is and how we rely on all of these mental shortcuts, it makes sense to people. And so it's fun to share with lots of people.”