As we’ve previously written, people tend to pair up romantically with partners who are about as attractive as they are. So the most attractive people pair up with each other, followed by the next most attractive people pairing up, etc., all the way down the attractiveness scale. Scientists call this assortative mating.1 How do we know this assortative mating occurs? There is a correlation between two partners’ levels of attractiveness. This means that as one partner’s attractiveness increases, the other partner tends to be more attractive as well. People want the best partner they can get, and the more attractive a person you are, the better mate you can snag.
Although we do have some scientific evidence for assortative mating, this phenomenon really only makes sense when it is very clear who the most attractive people are. And this is not always the case. Someone might view their partner as a 10, but everyone else sees him or her as a 5. Based on other research, we know that people in happy relationships tend to view their partners as better (more attractive, intelligent) than they objectively are — our minds are playing tricks on us. Scientists call this a positive illusion.2
The initial meeting period (when people don’t know each other very well) tends to be the time when perception of attractiveness between partners is the most objective and consistent with the consensus of others. The first time you see someone, your attractiveness radar is more in sync with everyone else’s and there is agreement about whom the hottest people are. This (initial attraction) is where we see strong evidence for assortative mating—the 10s with the 10s, 7s with the 7s, etc.
But what about after people have known each other for a long time? In this situation, people’s perceptions become more idiosyncratic, in part because they might have a lot more information available. The more time you spend with a person, the more you observe them in different contexts, and attractiveness becomes much more subjective. Sure enough, in longer-term contexts we see weaker evidence for assortative mating because there’s less consensus about who is hot when people know each other for a long time.3
In a new study4 the research team asked a sample of 167 couples how long they had known each other (as acquaintances) before they started dating. What they found was that for couples who knew each other for very little time (less than 1 month) there was a very strong correlation between each other’s attractiveness level (ranging between .53 and .72). But for couples who knew each other 9 months or more before dating, the correlation between partners’ attractiveness was basically zero.
A similar effect was found when the researchers asked couples if they were “friends” before dating (I put the word friends in quotation marks because it’s always possible that one partner could be secretly crushing on their friend). For those couples who were friends before dating, there was a much lower correlation between their attractiveness levels. So the take home point is that people are less likely to match their partners’ attractiveness level if they knew each other for a long time before they started dating.
What are the implications of this? Well for starters, we can dismiss the notion that physical attractiveness is a stable trait that never changes. We’re used to thinking about people as “hot or not” but that’s only true in a very limited context (when you first meet someone). Over time you can literally become hotter (or less hot), depending on your relationships with other people. After a while, the chubby, balding short guy (initially not very attractive) could be much more attractive to another person after they’ve known each other for a while and become close friends. When close friendships lead to romance (as they often do), people focus on other traits that make a person desirable.
Another implication might be that the best strategy to date someone “out of your league” is to become friends with them first and be patient. One of my childhood friends calls this “playing the long game.” However, we do not have any data yet about whether this is an effective strategy. It might work but only a small percentage of the time. Hopefully future research will help us discover whether “playing the long game” is generally successful, or if some people are more successful at it than others.
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1Lutz, F. E. (1905). Assortative mating in man. Science, 22, 249–250.
2Barelds, D. P. H., Dijkstra, P., Koudenburg, N., & Swami, V. (2011). An assessment of positive illusions of the physical attractiveness of romantic partners. Journal of Social and Personal Relationships, 28(5) 706–719.
3Eastwick, P. W., & Hunt, L. L. (2014). Relational mate value: Consensus and uniqueness in romantic evaluations. Journal of Personality and Social Psychology, 106, 728–751.
4Hunt, L. L., Eastwick, P. W., & Finkel, E. J. (in press). Leveling the playing field: Longer acquaintance predicts reduced assortative mating on attractiveness. Psychological Science.
Dr. Dylan Selterman – Science of Relationships articles | Website/CV
Dr. Selterman’s research focuses on secure vs. insecure personality in relationships. He studies how people dream about their romantic partners and how nighttime dreams are associated with daytime behavior. In addition, Dylan studies issues related to morality and ethics in relationships, including infidelity, betrayal, and jealousy. 
image source: itsbrianmcfadden.com
