Signaling Singleness: Mating Intelligence and Black Day

This post was co-authored with Jessica Fell Williams who is an MA student in Psychology at SUNY New Paltz and a member of the Evolutionary Psychology Lab. This is cross-posted at the Psychology Today blogs and at the blogroll for Oxford University Press.

On the 14th of April, single Koreans will signal their singleness by wearing, eating, and experiencing “black” as a statement on the nature of being single.

From the perspective of mating intelligence, following mating-relevant customs that are specific to one’s culture is crucial in mating. Knowing the rules and showing others that you can play by these rules is a signal to others that you have your stuff together. On this day in South Korea the rules are as follows: if you’re single, you’re to publicly display this fact by eating, wearing, and experiencing black. Doing so shows that you know what the rules are and that you’re willing and able to play by them. Ultimately, such a signal is attractive to potential mates and such signaling may, ironically, be a key to attracting mates on Black Day.

From an evolutionary perspective, the nature of pairbonding is ultimately rooted in the costs associated with parenting that typify our species. According to Trivers’ parental investment theory, in species that have relatively altricial (helpless at birth) offspring, mating systems favor pairbonding to help bring multiple adult helpers to assist with the raising of young. And humans fit this model in spades. Pair-bonding, a form of reciprocal attachment, is observed among humans in romantic relationships across cultures and social structures. Although the norms found vary quite a bit across cultures, most cultures have some sort of institutionalized guidelines on pair-bonding (often overlaying with marriage in an extended pair-bond situation).

Many modern cultures now experience (and socially accept) higher rates of single parenting and individuals marrying later in life. However, evolutionarily speaking, being shut out of the mating game, or in the case of a female, waiting too long, is a dead end for reproductive success. As such, it makes sense that cultural norms would address the issue of being single (as cultural norms often pertain to evolutionarily important issues such as mating, parenting, how to treat others, and so forth). At the very core of the matter is what many consider to be the ideal: reciprocal attachment, or pair-bonding, and the stigma associated with a lack thereof. Thus, it may be possible to infer that cultural norms aimed at recognizing “singleness” actually help develop signals that assist individuals in engaging in mate-seeking strategies.

Black Day seems to be a culturally specific way to acknowledge this issue of being single. Not only to support those who are unattached, but also to call attention to “singleness,” which ultimately can help people plan for mating-relevant aspects of their future. Outwardly, the process of commiserating with other singles may appear to be a way of establishing a similar in-group experience as those who have found themselves in relationships. But it also has the possibility of being more. Events designed by and for singles may help these singles “signal” to other unattached individuals that they are ready, willing, and able to invest in pair-bonding behavior.

Like the peacock that displays his plumage for potential mates despite the risk of being quickly eaten by predators, single people unite during holidays such as Black Day to display their wares in hopes of finding a kindred soul. By outwardly participating in the rituals of the celebration, they potentially place themselves at risk of being scorned by the elite group of those who are attached, but the potential to reap the evolutionary benefits may outweigh the costs. Effectively navigating such decisions is a crucial part of human mating intelligence.

In South Korea, donning all black clothing and going out to share the traditional comfort-food meal of noodles and black bean sauce could provide just the opportunity for single people to connect with others in the same position. These culturally specific customs provide an occasion for individuals to seek out and evaluate potential mates by engaging in a variety of evolutionarily based mating displays. In fact, in the absence of issues of mate-guarding, and potentially reduced intrasexual competition, singles on Black Day may have an even better chance at spending the next 14 April on the other side of the relationship fence.


Geher, G., & Kaufman, S. B. (2013). Mating intelligence unleashed: The role of the mind in sex, dating, and love. New York: Oxford University Press.

Trivers,R. (1972). Parental investment and sexual selection. In B. Campbell (Ed.), Sexual selection and the descent of man: 1871. Chicago: Aldine.



Glenn Geher

About Glenn Geher

Glenn Geher is professor and chair of psychology at the State University of New York at New Paltz. In addition to teaching courses at both the undergraduate and graduate levels, and conducting research in various areas related to evolutionary psychology, Glenn directs the campus’ EvoS program, one of the most successful, noteworthy, and vibrant features of a campus that prides itself (rightfully) on academic vibrance. In Building Darwin’s Bridges, Glenn addresses the details of New Paltz’s EvoS program as well as issues tied to the future of evolutionary studies in the rocky and often unpredictable landscape of higher education.
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