No one would be surprised to hear that we are often attracted to people with similar beliefs to our own. Research has shown that long-term couples align by ideology more often than any other trait besides religion. But a new study suggests that this attraction might be more biological than we previously thought. The study, published in the American Journal of Political Science, suggests that—to a small extent—we are attracted to the body odor of people with similar political opinions to our own.

The research team, led by Rose McDermott of Brown University, instructed the 146 participants to rate their own ideology on a seven-point scale from “extremely liberal” to “extremely conservative.” Of these 146 subjects, 21 with extreme ideologies were then designated as the lucky few to provide samples of their body odor.

After washing with fragrance-free shampoo and soap, the chosen ones wore gauze pads under their arms for 24 hours and were instructed to abstain from: “smoking, drinking, deodorants, perfumes, being around strong odors or candles, animals, eating strong-smelling foods, having sex, or sleeping in a bed with any other people or pets.”

The gauze pads were then returned to the lab, transferred into vials, and frozen for a week. Following the freezing period and a brief thawing, the remaining 125 participants acted as “evaluators,” and smelled the odor samples collected from the other subjects—people they had never seen—and rated their attractiveness.

Participants found the scent of those with whom they were ideologically similar to be preferable to those with opposing views. Some examples of this phenomenon were more prominent than others. In one instance, a subject stated that the sample (from an opposing political view) had “gone rancid.” Immediately afterward, another evaluator (with a similar ideology to the sample-provider) reportedly asked the researchers if she could keep the vial, because it was “the best perfume she’d ever smelled.”

Ultimately, the researchers claim that attraction to people with similar beliefs may be a residual component of “a more primitive behavioral adaptation designed to ensure reproductive success.” It makes evolutionary sense for us to be attracted to people we agree with, as this often increases the chances of a successful long-term relationship. While most of the mate selection process likely happens consciously, with intelligent decisions informing our choices more so than “more basic physical desires,” these subtle whiffs may affect our moods and hormone regulation.

Of course, many other factors play into sexual attraction beyond odor attraction, and ideology is by no means the only influence on odor attraction—which the researchers readily acknowledge. They write: “The influence of smell constitutes only one of thousands of potential factors that operate as part of the complex interaction between local ecology, immediate environment, parenting, culture, physiology, and neurobiology.” Despite this research, we probably won’t be trying to sniff out our soulmates any time soon.