Yet alongside this consensus is an equally important concept: uniqueness. Uniqueness can also be measured. It is the degree to which someone rates a specific person as lower or higher than the person’s consensus value. For example, even if Neil is a 6 on average, certain women may vary in their impressions of him. Amanda fails to be charmed by his obscure literary references and thinks he is a 3. Yet Eileen thinks he is a 9; she finds his allusions captivating.

In initial encounters, consensus and uniqueness are in tension. Which ultimately prevails?

In answering this question, it is crucial to keep in mind the obvious (but underappreciated) fact that most people do not initiate romantic relationships immediately after forming first impressions of each other. One recent study of a representative sample of adolescents found that only 6 percent reported that they and their partners formed a romantic relationship soon after meeting.

It seems most likely that it is the consensually desirable people who pull off the rare feat of quickly leveraging an initial positive impression into romance, while a vast majority of us get to know our romantic partners slowly, gradually, over time. Most of us have networks of opposite-sex friends and acquaintances. And even though we would never consider many of them as romantic partners, for a handful, all it would take is the right moment and a spark. These are the contexts that produce most romantic liaisons — and as our recent work shows, these contexts reveal very little consensus with respect to mate value.

For one of our studies, we recruited 129 heterosexual individuals across several small undergraduate classes. These individuals indicated, at both the beginning and the end of the semester, the extent to which the opposite-sex students in their class possessed a set of desirable qualities. We found that consensus dropped and uniqueness increased as these students got to know one another over time. After three months, uniqueness dominated consensus for all desirable qualities: attractiveness, vitality, warmth, potential for success and even the ability to provide a satisfying romantic relationship.

In a related study of approximately 350 heterosexual individuals, we collected these same measures in networks of opposite-sex friends, acquaintances and partners. Among these well-acquainted individuals, consensus on measures of mate value was nearly zero. These are the people who know what authors you like, what you wore for Halloween six years ago and what obscure movie you will quote the next time you all get together. But they cannot agree on your mate value. Over the years, it has evaporated before their eyes.