Psychologists tend to disagree with that theory. In another experimental mock speed-dating event, subjects who thought they were similar to one another were more likely to be attracted to each other, but that wasn’t the case for those who were actually similar to one another.

“People are not romantically attracted to people who look like them,” Zebrowitz said. “That has to do with the disadvantages of mating with your brother, for example.”

Indeed, Lisa DeBruine, a psychologist at the University of Glasgow in the U.K., has found that people find self-resembling, opposite-sex faces to be trustworthy, but not sexy, and they can even be repulsive for a short-term relationship.

But George Michael and Maeby might be relieved to know that while excessive genetic overlap between two people results in poor reproductive prospects, a small amount can be acceptable. That might be why 20 young Norwegian couples rated their partner’s photograph as more attractive when it was digitally “morphed” to look ever so slightly more like themselves. The magic number was a 22 percent resemblance—any more similar was deemed gross.

And, by the way, you really should call the whole thing off if one of you says potato and the other “po-tah-to” (because after all, who says it like that?). Couples with similar speech styles were more likely to stay together than those who speak differently.

DeBruine points out that though we’re programmed to avoid dating our relatives, we also have a certain, subconscious affinity for our own parents.

“The scientific evidence reflects complexity and suggests that there may be a ‘happy medium,’” DeBruine told me. “But, ultimately, other factors are much more important in successful relationships.”

Will my online dating attempts lead to a relationship?

We may have more options for potential mates than ever before, but unfortunately people have trouble determining what they really want in their lovers. One 2008 study by Eli Finkel and Paul Eastwick at Northwestern University found, for example, that though men and women tend to say they prioritize different things in their mates (men are more likely to emphasize looks and women money), there’s no difference in the types of mates the two sexes actually choose in a real-life setting—which the authors gauged using a speed-dating exercise.

What’s more, there was little association between the traits participants said they wanted in a partner on paper and what they actually liked about the mates at the speed dating event. In other words, you may flaunt your Rolex in your Tinder photo, but that might not stop your date from heading home with a scruffy artist once you’re at the bar.

This is in part because the way people pair with one another on dating sites is different from the way they will then later evaluate the relationship, according to Finkel and Eastwick. People browse online profiles in what’s known as “joint evaluation mode,” comparing multiple suitors against one another on the basis of attractiveness, income, and other factors. But they make relationship decisions in what’s called “separate evaluation mode,” judging just that person and thinking, “Is this person right for me?” Even if you pick out the prospect with the most striking jawline, and you may overlook the one who will willingly spend hours watching Cake Boss with you, sans judgement.