Not so long ago we had to rely on chance to introduce us to our love matches. We liked to call it “fate,” and make sweet movies celebrating the blind date and happy accident. Now, though, thanks to a merging of the social and digital spaces, matchmaking sites are flourishing based on making the search for love more predictable.

Sure, a big draw of matchmaking sites is that they take the ‘chance’ out of ‘chance meeting’, but the real hook may be in the scientific precision of the online personality inventory, guaranteed to match us with the optimal mate.

As it turns out, though, the heart knows a lot more about these things than the head. A recent study conducted Eli Finkel of Northwestern University found that people choose the more compatible mate by following their gut, not the rational list of optimal personality traits spat out by a matchmaking algorithm.

The same idea of emotional response applies to brands. Often “what people want” is based on an inventory of items that have been reported from that rational side of us—you know, that way we like to think of ourselves as logical and making decisions based on that logic. But, as Brand Keys has found, people choose brands like they choose mates: more on basis of emotional factors than rational ones. In fact, that ratio is 70:30 heart-over-head.

What’s the cautionary tale for the brand manager here? Thinking too much about a logical set of preferences, like superficial commonalities between people, can distort your ability to identify what has real meaning.

In love as in brands, “the heart has its reasons which reason knows nothing of.” Remembering this will keep your brand from ever skipping a beat.