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This could be a deal breaker.

Melissa Locker
August 15, 2017

When you’re trolling Tinder for a new life partner, skip the talk of religion or politics and ask dates about whether they prefer Coke or Pepsi. That’s according to a new study from a team at Duke University's Fuqua School of Business who found that so-called “brand incompatibility” can slowly erode a relationship. Turns out whether you have the same belief in brands, may be more important to a long and happy relationship than other shared interests or religious beliefs.

The researchers tracked individuals and couples for over two years, looking at brand preferences for products like soda, coffee, chocolate, beer and cars. In addition to asking whether they prefer Starbucks or Dunkin', they also looked at power dynamics within the relationship as well as overall happiness. Those couples that agreed on preferred brands were generally happier. "It's an extremely robust effect, we found it over and over and over again," said Professor Gavan Fitzsimons, who worked on the study, in a statement.

While flight attendants and waiters would have us believe that Coke and Pepsi are more or less interchangeable, true soda devotees know that when it comes to cola, you’re either a Coke fan or a Pepsi fan and there is no substitute. The Duke team’s findings, "Coke vs. Pepsi: Brand Compatibility, Relationship Power, and Life Satisfaction," were just published in the Journal of Consumer Research and they showed that those of us with strongly-held beliefs about Pepsi vs Coke fans are the Romeo and Juliet of the grocery store aisle, and a long-term relationship just might be doomed from the start.

The study asserts that over the course of a marriage, if one person constantly comes home from the store with Pepsi, while their partner prefers Coke, it can start to grate. "Most couples won't break up over brand incompatibility, but it leads to the low power partner becoming less and less happy," said Danielle Brick, who also worked on the study. “11 years into a relationship, when he or she keeps coming home with Pepsi, day in and day out, it might start to cause a little conflict. And if you're the low-power person in the relationship, who continually loses out on brands and is stuck with your partner's preferences, you are going to be less happy."

So, when you’re embarking on a new relationship, perhaps take a quick trip through the drive-thru and see what soda they choose. Or, as Fitzsimons notes: "People who are looking for love should maybe consider including brand preferences on their dating profiles.”