We Love Those Who Are Similar to Us

Posted on February 12, 2022 by Victor Karandashev

“Similarity psychology” and positive assortative mating play an important role in love relationships. We like others who are not only beautiful but also similar to ourselves.

It seems natural to like and love those who are beautiful. Men and women tend to favor physically attractive men and women. When asked, they frequently express their preferences for good-looking prospective partners (Buss and others). Do they really choose those with attractive appearances for a relationship? Are men more likely to fall in love with beautiful women than women are to fall in love with handsome men?

Do We Love Others Who Are Beautiful or Similar to Us?

The puzzle remains: if beautiful women and men are so attractive, why don’t we fall in love with the most beautiful ones? Three explanations are possible.

Men and women perceive them as beautiful yet unattainable. The anxiety of not being accepted by a beautiful person makes them cautious, even subconsciously, to avoid the frustration of implied and tacit rejection. This might work as a psychological defense mechanism.
It is possible that we love someone for reasons other than their beauty. Beauty just adds to our admiration. However, causation can also work in the opposite way: we perceive our beloved as beautiful because we love him or her.
People tend to prefer homogamy in relationships and similarity with another person in their physical appearance and other personal, social, and cultural features.

Let us consider how “similarity psychology” and positive assortative mating work in love relationships.

“Similarity Psychology” Attracts Us to Similar Men and Women

The early studies showed that partners in marriage were more likely to resemble each other than to differ in physical and psychological traits, even though those similarities and differences varied among social characteristics (Brockner & Swap, 1976; Burgess & Wallin, 1943).

The similarity in values, beliefs, attitudes, and personality traits also plays a role in the choice of a mating partner. Partners with similar attitudes, as well as those who see each other more frequently, are more attracted to each other in general (Aron et al., 1989; Byrne et al., 1971).

The studies in different cultures confirmed these tendencies.

In the 1990s, a large survey of the Spanish population showed that individuals are more likely to fall in love with potential partners who they view as similar to themselves in physical attractiveness (Yela & Sangrador, 2001).

Due to romantic idealization, they have a positive bias toward a partner and perceive him or her as a little more attractive than themselves. Over the course of a long-term relationship, habituation diminishes the value of the partner’s physical attractiveness. Over time, familiarity and cognitive dissonance counterbalance physical attractiveness. The role of these and other attributes increases.

How Positive Assortative Mating Works

There is strong evidence that people who prefer positive assortative mating choose to mate with those who are similar to themselves. This type of selection—also called homogamy—is quite common in several individual characteristics.

Positive assortative mating also works with physical traits. For example, a person of short stature tends to mate with another person of similar height. This tendency of men and women to select mating partners with similar phenotypes motivates them to fall in love with those of similar physical appearance.

Many studies have demonstrated that individuals prefer relationships with others who have physical characteristics similar to themselves (e.g., Bereczkei et al., 2002; Zajonc et al., 1987).

Furthermore, individuals decide to initiate a dating relationship with those whose “social desirability” is similar to their own. They are associated with a lower likelihood of possible rejection (Berscheid et al., 1971).

Why Do Mates Look Alike?

Two effects can play roles in such preferences:

early childhood imprinting and
self-referent phenotype matching.

The relationship with caregivers during childhood plays a role. The early childhood imprinting of caregiving experiences can shape the expectations of desirable partners for mating (e.g., Bateson, 2004; Bereczkei et al, 2004).

Specifically, due to sexual imprinting, people see others they grew up with as sexually attractive. The opposite-sex caregiver’s phenotype can be used as a model for future mate preference. This can be a parent, stepparent, or other early caregiver with whom a child spends much of their time in the early years. For example, women tend to choose partners that resemble their adoptive fathers (Bereczkei et al., 2004).

Due to self-referential phenotype matching, an individual may prefer a person who resembles themselves. Or, alternatively, the homogamy can be due to the sexual imprinting of the parents in childhood. The results of the study demonstrated that a tendency to homogamy in facial characteristics between partners in a relationship really exists and occurs largely due to self-referent phenotype matching and, to some degree, due to sexual imprinting (Nojo et al., 2012).

Do Partners Become Alike Over the Course of a Relationship?

Since men and women prefer phenotypically similar mates, this leads to mating homogamy in physical traits between partners.

Another factor can also play a role in increasing facial homogamy.

One study demonstrated that partners who live with each other for a long period of time become physically similar in their facial features. Their facial similarity increases and becomes apparent after 25 years of cohabitation. Moreover, those with such an increasing resemblance experienced greater marital happiness. The authors proposed a “vascular theory of emotional efference” (VTEE) to explain this effect (McIntosh, Zajonc, et al., 1997; Zajonc et al., 1987).

According to this idea, emotional processes cause vascular alterations that are influenced in part by facial musculature. The face muscles are thought to operate as ligatures on veins and arteries, allowing blood to be diverted away from or directed toward the brain. As a result, habitual usage of facial musculature may have a long-term effect on facial features. Two people who have lived together for a long time will develop physical similarities in their facial features as a result of frequent empathic imitation. Kin resemblance may thus be more than just a result of shared genes but also of long-term social contact and the mere exposure effect.

The Other Articles of Interest on the Topic

Genetic Secrets of Love Attraction

Attraction to Familiar Others

Genetic Diversity and Genetic Sexual Attraction

Our Predisposition to Homogamy in Love

Sexual Preferences for Physical Attractiveness

What’s an Ideal Age Difference in Dating?

Physical Beauty of Men and Women Across Cultures

Women and Men Who Are Physically Attractive in Different Cultures

Sexual Preferences for Physical Attractiveness

Posted on February 1, 2022 by Victor Karandashev

To what extent do men and women place different values on different aspects of physical attractiveness when trying to mate?

Evolutionary science gives us important keys for better understanding the mating value of physical attractiveness. However, despite the general universality of evolution, its specific evolutionary principles and mechanisms vary across species and cultures. Many of them refer to sex differences.

Let us consider sexual differences in the value of physical attractiveness in mating.

Why Do Male and Female Animals and Birds Look Different?

Physical appearance helps sexually dimorphic animals and humans select a mate. Many species, including mammals and birds, have their own mate preferences and focus their courtship energy on those favorites (see e.g., Andersson 1994; Fisher, 1998).

When it comes to mating and sexual relations, they are not promiscuous. They are picky and won’t mate with just anyone. They communicate their love and attraction.

“They stroke, kiss, nip, nuzzle, pat, tap, lick, tug, or playfully chase this chosen one. Some sing. Some whinny. Some squeak, croak, or bark. Some dance. Some strut. Some preen. Some chase. Most play”
(Fisher, 2004, p.27).

Males and females differ in appearance and behavior. As I noted elsewhere, in some species, like birds, evolutionary mechanisms tend to beautify males, making their appearance attractive for female mates. They need to be distinctive and attract a potential female for mating. On the other hand, the appearance of females is less appealing among those species. It seems they are on demand anyway (Prum, 2017).

How Women and Men Appreciate their Partners’ Physical Attractiveness: Evolutionary Explanation

People are different in this respect. According to presumed human evolutionary mechanisms, women are more frequently concerned about their appearance and beauty compared to men, who care about this much less (see for review, e.g. Buss, 1994; Feingold, 1990).

These sex differences might be due to human evolutionary roots, which determine the different mating strategies of males and females. Here is an evolutionary interpretation of sex differences in mating. Since women and men have different contributions to the reproduction of offspring, they have different mating strategies and different parental investments (Buss 1989, Trivers, 1972).

Cross-cultural consistencies of these sex differences support such an evolutionary interpretation. Men place a higher value on their female partner’s physical attractiveness in mating relationships. Studies have shown such evidence across many cultural samples worldwide (e.g., Buss, 1989, 1994; Buss et al., 1990; Buss, Shackelford, Kirkpatrick, & Larsen, 2001; Feingold, 1992; Fletcher, Tither, O’Loughlin, Friesen, & Overall, 2004; Langlois et al. 2000; Shackelford, Schmitt, & Buss, 2005; Sugiyama, 2005; Townsend & Wasserman, 1998, see for review, Karandashev, 2022a,).

Here are some cultural examples. In Arab Jordanian society, men prefer young and attractive prospective female mates for long-term relationships. On the other hand, Jordanian women place less value on these characteristics in men when mating (Khallad, 2005).

Another study of Muslims living in the United States found that in their personal advertisements on a matrimonial Web site, women more often described their physical attractiveness compared to men’s self-descriptions. However, these gender differences in preferences for a physically attractive mate are not significant. Nonetheless, men are more interested in their younger and more attractive mates than women are (Badahdah & Tiemann, 2005).

How Men and Women Value their Partners’ Physical Attractiveness: Cultural Explanation

Cultural interpretation of sex differences in the value they place on physical appearance in mating and dating is also possible. These differences might be due to cultural gender stereotypes. Patriarchal cultures, which have been prevalent in many societies for centuries, encouraged men to rely on their wealth as a mating value. So their appearance was of less mating value. On the other hand, women’s cultural roles left them dependent on men for their survival and wealth. Therefore, they could rely largely on their appearance and ability to reproduce.

History, however, has demonstrated much more diversity in gender roles, which did not necessarily follow these cultural patterns. In some societies and social circles, women might play different roles. For example, in many agrarian societies, women’s abilities to cook and work hard were more important than their beauty (Karandashev, 2017).

The current reality of social life across cultures, however, presents a diversity of gender differences and similarities that may go beyond the simple evolutionary explanation. Many modern men love to beautify themselves, while many modern women do not care about this.

Genetic Diversity and Genetic Sexual Attraction

Posted on January 26, 2022 by Victor Karandashev

Despite the importance of similarity in genetic sexual attraction, genetic diversity is equally important in love. It appears that both similarities and differences between love partners play important roles.

Evolutionary Value of Genetic Diversity

Genetic sexual attraction plays an important role in triggering love between men and women. However, sexual attraction for sexual reproduction also strives to avoid the negative effect of excessive genetic similarity between loving partners. Inbreeding has a deleterious biological effect on the offspring in terms of health quality, the likelihood of diseases, disabilities, and mortality (see for review, Ceballos et all, 2021; Hasselgren & Norén, 2019).

Therefore, human evolution and population growth throughout history have promoted people to exclude mates with extreme genetic similarity from the pool of possible mating partners. Such mating increases the likelihood of harmful recessive genes and reduces offspring fitness (Ceballos et all, 2021).

Cultural Evolution Encourages Diversity in Genetic Sexual Attraction

Even though consanguineous marriages—mating relations with blood relatives—have been widespread throughout history, cultural norms of incest taboos have evolved in many societies to safeguard against this harmful effect of inbreeding. People likely became aware of the harmful effect of sexual relations between close relatives on the quality of their offspring. Incest, or sex between family members, became a cultural taboo in many societies. Evolving social norms and psychological experiences of love began to respect the principles of biological evolution. They were adjusted accordingly, encouraging the extended reproduction of offspring.

A Controversy over Genetic Sexual Attraction among Family Members

Although people perceive potential mates who resemble their kin as more sexually appealing, incest avoidance evolves from the development of taboos. When awareness of the kin relationship between self and other is bypassed, relatives often look sexually appealing to a person. So, by only consciously acknowledging incest taboos, people suppress their sexual attraction to kin (Fraley & Marks, 2010).

The Benefits of Diversity in Genetic Sexual Attraction Encourage Cultural Taboos against Incest

The difference between partners in their genetics leads to healthier offspring. Therefore, natural selection—and cultural norms accordingly—developed protective psychological mechanisms to decrease the sexual drive for similarity and allow only a suitable measure of variance between partners in love relationships. This evolutionary mechanism might be at the origin of the strong incest taboo among many populations of species and human societies (Lampert 1997, p.14).

Societies in history and modern times have respected the incest taboo, prohibiting sexual relations between females and males who are in kinship relationships. Many human societies have cultural norms prohibiting sexual relations among kin (Lampert, 1997; Murdock, 1949; Westermarck, 1891/1921).

References

Ceballos, F. C., Gürün, K., Altınışık, N. E., Gemici, H. C., Karamurat, C., Koptekin, D., … & Somel, M. (2021). Human inbreeding has decreased in time through the Holocene. Current Biology, 31(17), 3925-3934.

Hasselgren, M., & Norén, K. (2019). Inbreeding in natural mammal populations: historical perspectives and future challenges. Mammal Review, 49(4), 369-383.

Fraley, R. C., & Marks, M. J. (2010). Westermarck, Freud, and the incest taboo: Does familial resemblance activate sexual attraction?. Personality and Social Psychology Bulletin, 36(9), 1202-1212.

Lampert, A. (1997). The evolution of love. Praeger.

Murdock, G.P. (1949). Social structure. Macmillan.

Westermarck, E. (1921). The history of human marriage (5th ed.). London, UK: Allerton. (Original work published 1891).

Genetic Secrets of Love Attraction

Posted on January 25, 2022 by Victor Karandashev

From a biological evolutionary perspective, the genetic similarity must be important for sexual attraction. Intersexual attraction helps sexually dimorphic animals, such as birds and mammals, select a proper mate because they cannot reproduce offspring with anyone. They can do this only with those with whom mating success is possible and higher than with others (Karp et al., 2017; McPherson & Chenoweth, 2012; Owens & Hartley, 1998; Rigby & Kulathinal, 2015).

Do People Fall in Love with Genetically Similar Others?

For a weird example, a human individual can be attracted by a sexual relationship with a horse, cow, goat, or gorilla. They can even be a nice couple. They may attain sexual pleasure. Nevertheless, such relationships, from an evolutionary point of view, are wasteful expenditures of energy because they are destined to be childless. They are genetically too distant to produce offspring.

However, humans and chimpanzees are more similar in this regard—they have a genetic distance of less than 2%. Therefore, reproductive success in that case could be possible (Lampert 1997).

Therefore, we can expect that genetic factors and corresponding similarities in the physical appearance and chemistry of human individuals can determine their sexual and love attraction. The chemistry of love, which makes some partners more compatible with each other than others, can be real, not metaphorical.

Do we have a genetic predisposition to fall in love with someone?

Optimal Genetic Similarity

In biology, the principle of optimal genetic similarity is important for the evolutionary selection of partners among animals (Lampert 1997). Individuals tend to be attracted to others who are genetically similar to them. However, they prefer to keep their distance from those who are genetically very dissimilar from them. Both factors play their roles in the selection of mating partners with optimal genetic similarity to them.

This principle of genetic similarity may also work among humans. An individual tends to fall in love with a person who, to some extent, is genetically and physically similar. Biological evolution has developed a psychological mechanism that unconsciously attracts individuals to mates who are similar and excludes those who are significantly different.

Why Are Genetically Similar People Sexually Attractive to Us?

Here is one piece of evidence that such an unconscious attraction is possible (Rushton, 1988). Rushton examined the thousands of court cases in which courts investigated the validity of fatherhood. Genetic testing was used to identify whether a man with whom a woman had sex was actually the father of her baby. Examining those cases, Rushton (1988) was interested in knowing how men and women, at the beginning of their sexual relationship—at the time of conceiving a baby—were genetically similar to each other. The data showed that they were genetically more similar to each other than a random couple. These results indicated that it was likely that potential mates unconsciously recognized their genetic similarity with a partner and, therefore, felt sexual attraction (Rushton, 1988).

Another study used genome-wide SNPs and also supported this genetic similarity explanation of sexual attraction. In a sample of American Whites (non-Hispanic), researchers found that married partners are genetically similar to each other—more than random pairs of individuals (Domingue, Fletcher, Conley, & Boardman, 2014).

The Words of Tentative Limitations

It shall be acknowledged, however, that these findings are descriptive and can be considered tentatively true for a causational explanation. The genetic similarity between partners can be due not only to their genetic assortative mating but also to their shared ancestry (Abdellaoui, Verweij, & Zietsch, 2014). The genetic similarities in couples can be due to genetic population stratification that evolved in a society due to geographical proximity, social homogamy, and ethnic homogamy.

Are Close Relatives More Likely to Fall in Love?

According to the findings presented above, genetically similar relatives in nuclear and extended families perceive each other as physically similar and attractive. Does the genetic similarity of close relatives make them more likely to be attractive and love each other? For example, they can perceive each other as more sexually appealing. Then, the psychoanalytic myths of a boy’s unconscious sexual attraction to his mother (the Oedipus complex) and a girl’s attraction to her father (Electra complex) can be partially true due to their genetic similarity, although the effect of imprinting can also play a role.

Many cases of consanguinity in sexual relationships and marriages have been documented throughout history. In these cases, blood relatives find each other attractive (see Karandashev, 2017, 2022 in press for a review). Consanguineous marriages are still widespread and preferred in many societies in West Asia, the Middle East, and North Africa (e.g., El-Hazmi et al., 1995; Hamamy, 2012). Surprisingly, these cultural traditions have been persistent.

However, the negative impact of incest (sexual intercourse with a child, sibling, grandchild, or parent) on offspring is well documented. Therefore, to safeguard against this harmful effect of incest, cultural norms and incest taboos have evolved in many cultures.

The Diversity of Love

Category Archives: the biology of love