I. INTRODUCTION

The present article aimed to investigate if there were differences – and which – between partner selection criteria of females in long term relationships that desired and that did not desire children with their current male partners. Data consisted of 288 answers to the research questionnaire aimed at cisgender, heterosexual and nulliparous women currently in a relationship, which evaluated the presence or absence of 23 certain traits in their current male partners. From them on, the aim was to statically evaluate the existence of significative differences between percentage frequency of answers regarding both groups of women and to assess whether findings could be in agreement with the female partner selection model proposed by evolutionary psychology, which is based on male direct or indirect parental investment.

II. PARTNER SELECTION CRITERIA IN HETEROSEXUAL MALES AND FEMALES: AN EVOLUTIONARY PSYCHOLOGY BASED PERSPECTIVE

According to the theory of evolution, behaviors, the mind and culture itself emerged through the union of genetics and the evolutionary environment of the species (epigenetics). Therefore, trying to break the human individual into biological and non-biological (natural and cultural) would mean perpetuating an ancient dualism (BARKOW ET AL, 1992), when actually both instances constantly act conjointly and indivisibly. To Evolutionary Psychology, the existence of a bigger brain in the Homo genus (DE TONI ET AL, 2004) accounted for a range of new cultural developments even before the emergence of the Homo sapiens (CARVALHO, 1989). Therefore, the process of humanization was deeply characterized by cultural specialization (BUSSAB & RIBEIRO, 1998) consisting of a process in which culture created a human being that was capable of creating culture. The initially developed cultural context subsequently promoted the natural selection of new cerebral specialization, which would, by itself, produce more culture (CARVALHO, 1989). In this sense, what occurred during the process of hominization consisted of a natural aptitude for culture and a cultural aptitude for developing human nature (BUSSAB & RIBEIRO, 1998). Cultural evolution is not to be considered separately from natural selection, but rather its ultimate consequence. Culture has been present since the beginning of human evolution and has led humans towards becoming the species we currently are, even before the emergence of the Homo sapiens, having produced the brain that currently produces it (CARVALHO, 1989).

That being the case, it would be erroneous to consider that, once biological evolution produced a being that is physically capable of producing culture, he would break away from nature and start existing independently from it (CARVALHO, 1989). The human being is not currently free from its nature and immersed in culture, (BUSSAB & RIBEIRO, 1998), as to

Evolutionary Psychology, nature and culture are intimately and indissociably connected: the human being is, in perspective, biologically cultural. In this sense, Evolutionary Psychology suggests the existence of generationally selected and transmitted psychological mechanisms, which came to be as fruit of the interaction between natural selection and cultural evolution in the ancestral evolutionary environment. These mechanisms have established behavioral patterns (ADES, 2009) and are directly influenced by current cultural factors. The aim of evolutionary theories is to understand in which ways does this influence occur (VIEIRA & PRADO, 2004).

When it comes to psychological mechanisms related to sexual and parental behavior, TRIVERS (1972) developed the Parental Investment Theory and defined it as any investment made by the parents of a descendant in the direction of increasing his chance of survival and future reproduction, leading to greater reproductive success of the species. (VIEIRA & PRADO, 2003). Evolution has led to both men and women being required to practice parental investment (TOKUMARU & BERGAMIN, 2005). Female parental investment has always been direct; however, male parental investment could be direct or indirect (HEWLETT, 1992; LORDELO ET AL, 2006). Fathers in the evolutionary environment aimed to seek resources that would allow care, feeding, support and protection of mothers (indirect investment) and of descendants (direct investment), along with the transmission of culture in the form of instructions and guidance (BUSS & SCHMITT, 1993; BOSSARDI & VIEIRA, 2010). Parental Investment Theory is considered to be the main influence of sexual selection (BORRIONE & LORDELO, 2005), which is, of female and male partner selection criteria. This states direct relationship between the type and degree of parental investment practiced by each and the specificities of their partner selection criteria.

When it comes to female partner selection criteria for long term relationships, BUSS (1999) states that once ancestral women practiced intense parental investment, there used to be a great cost for not choosing a partner wisely. Therefore, through evolutionarily selected psychological mechanisms, women have proceeded to select their partners based on indicators of genetic quality and quality of male parental investment (BUSS & SCHMITT, 1993). Among these indicators are the preference for men of good economic resources, good financial prospects, social status, ambition, stability, athletic figure, good health, interest and willingness to invest in children, and also who are older, loving and dependable (BUSS, 1999). The specificities of these indicators may vary depending on the culture of each society, however, in all of them what is sought by the female is still an indicator of indirect or direct male parental investment.

While male parental investment could be direct and indirect, female investment was always direct and involved mostly being fertile, having good health and caring for descendants. BUSS (1999) states that for a man to be reproductively successful, there was the need for them to be in relationships with fertile and caring women, who would provide general care to descendants. Female parental investment consists of gestation, lactation, protection and care for children. Therefore, through evolutionarily selected psychological mechanisms, men have proceeded to prefer female traits directly related to their ability to bear healthy children. In other words, men proceeded to seek for indicators of fertility, reproductive value and health.

In broader research, BUSS (1989) aimed to investigate if the same partner selection criteria would appear in different cultural contexts. A total of 33 countries in six continents and five islands were visited, and 37 cultural samples were extracted. As a result, BUSS (1989) denoted that in 36 out of 37 samples, women have valued the potential for economic gain, good financial prospect and ambition in men more than men have valued these traits in women. At the same time, women have valued traits of physical attraction and good appearance in men less than men have valued these traits in women. Women preferred men averagely 3.42 years older than them and men preferred women who were averagely 2.66 years younger. In no sample have men preferred women who were older than them.

BECH-SORENSEN & POLLET (2016) concluded that differences between male and female partner selection criteria for long term relationships have remained stable through the last decades. In this sense, women more than men tend to prefer partners who are older and to value financial gain. Men more than women tend to prioritize physical attraction. WANG ET AL (2018) have statistically demonstrated that women are around a thousand times more sensible to financial gain criteria in a potential partner than men. They also found that men tend to be successful in compensating lack of physical attraction with high level of material resources.

FALES ET AL (2016) determined that women tend to prefer stable financial gain, good current wage, equal or superior level of resources and a successful career more than men tend to prefer those in women. Men tend to prefer good appearance and attractive figure more than women tend to prefer these in men. Lastly, SOUZA ET AL (2016) found that men generally preferred younger female partners while women preferred older male partners. Women tend to value good capacity of financial gain, good prospect of future gains, social status and ambition more than men value these in women. On the other hand, men tend to value physical criteria related to fertility and youth such as silky and lustrous hair, white teeth, symmetrical face and low waist-to-hip ratio in women more than women in men.

Both men and women were evidenced to equally value mutual attraction, love, kindness and intelligence.

III. METHOD

Participants were chosen based on four previously stated criteria: cisgender, heterosexual and nulliparous women of any age, who were in a long-term relationship with a male partner. These women could desire or not desire to have children, now or in the future, with their current partners. Two large populations were therefore compared: 1) Cisgender, heterosexual and nulliparous women in a relationship who desired to have children with their current partners and 2) Cisgender, heterosexual and nulliparous women in a relationship who did not desire to have children with their current partners.

Data collection instrument consisted of an online questionnaire presented with Google Forms and formulated based on BUSS (1989). The first part of the questionnaire consisted of preliminary data after criteria for inclusion of participants was previously met and the second part inquired about partner selection criteria per se, as it follows:

Part 1: Preliminary Data: age of female participant and age of partner, frequency of contraception usage, types of contraception used, desire to have children or preference to be childless.

Part 2: Attribution of Likert Scale regarding presence or absence of each one of 23 traits in current male partner, where1 (Strongly Disagree), 2 (Disagree), 3 (Undecided), 4 (Agree) and 5 (Strongly Agree).

Through Fisher Exact Tests, the answer to each trait was separately analyzed in order to reveal if there were significant differences between the percentage frequency of answers of both compared groups. Each Test led to a value of p. P being lower than 0.1 indicates significant difference between compared percentage frequencies, whereas P being greater or equal to 0.1 does not. Statistical significance was of 10%.

IV. ANALYSIS OF RESULTS

a) Traits without Significative Differences

The following 13 traits (2, 5, 7, 9, 13, 15, 17, 18, 19, 23, 25, 26 and 27) did not evidence significant differences between percentage frequency of answers of women who desired and who did not desire children with their current male partners (p≥0.1):

Chart 1: Traits without significant differences between percentage frequency of answers in both groups

b) Traits with Significative Differences

The following 14 traits (1, 3, 4, 6, 8, 10, 11, 12, 14, 16, 20, 21, 22 and 24) did evidence significative differences between percentage frequency of answers of women who desired and who did not desire children with their current male partners (p<0.1):

Chart 2: Traits with significant differences between percentage frequency of answers in both groups

In order to understand the specificities of differences between answers of the two compared groups in each trait, percentages of Strongly Agree (5) and Agree (4) were added, as well as percentages of Strongly Disagree (1) and Disagree (2). In all of them, women who desired children have agreed more and either disagreed equally or less than women who did not desire children with mentioned traits being present in their male partners.

V. DISCUSSION AND CONCLUSIONS

Out of 27 traits, 14 exhibited significative differences in percentage frequency of answers of women who desired and who did not desire children, where women who desired children agreed more with the mentioned trait being present; whereas the other 13 traits did not exhibit significative differences. When it comes to the first 14 traits, all of them are, aside from culturally valued, directly indicative of male parental investment and genetic quality. Similar educational background, good earning capacity and good education and intelligence all indicate possession of resources to be invested by the male, where the first could mean the same ability to transmit culture to children as the mother (direct parental investment); and the other two could mean the ability to obtain material resources to invest in both the mother and the children (indirect and direct investment). Similarly, desire for home and children, mutual attraction, easygoing and dependable are traits that not only establish greater proximity and care for the woman and children, but also guarantee that available resources will be invested in them. Lastly, good-looking, good health and physical attraction are indicative of genetic quality.

In addition, women who desired children are in majority 21 to 25 and in minority 41 to 66, whereas women who did not desire children are in majority 31 to 40 and in minority 18 to 21. The majority of women who desired children were therefore currently experiencing the peak of their fertility and reproductive value, while the minority of them is already experiencing intense and progressive decline in fertility. Similarly, the majority of women who did not desire children are past their fertility peak and the minority of them is currently at the beginning of their greatest fertile period. Finally, women who did not desire children are 10% more of older age than their partners when compared to women who desired children. Preference for older male partners could be related to their greater possession of resources and greater ability to transmit culture for children than younger partners, whereas for women who did not desire children, there is less concern about having younger partners.

When it comes to the other 13 traits, all of them appear to be equally indicative of parental investment and culturally valued. Good cook and housekeeper, organized and refined are traits that both allow for the ability to take care of women and children, but are also fruit of an increasing cultural value attributed to men who are able to perform domestic tasks. Good social class and hardworking are traits that indicate the possibility of providing resources for woman and children, however at the same time, they do not indicate guarantee of actual investment being performed. Emotional stability and maturity, kind and understanding, sociability, inspiring personality, creative and artistic, good conversationalist, same religious and political beliefs are generic traits that tend to inhabit an imaginary of cultural idealization. A partner in possession of these traits is, apart from potentially able to invest in women and children, also culturally attractive.

In this sense, it would be erroneous to say that selecting a male partner who possesses certain traits is an entirely cultural or evolutionarily selected behavior. In both groups compared, women have selected male traits that are indicators of both male parental investment and genetic quality, but also of cultural value. However, results showed that partners of women who desire children tend to possess more traits directly related to the ability and tendency of practicing parental investment and of genetic quality than partners of women who do not desire children. On the other hand, when it comes to male traits that are equally indicative of parental investment and culturally valued, there have been no significant differences between selection criteria of women who desire and who do not desire children.

It is therefore possible to conclude that evolutionarily selected female psychological mechanisms regarding partner selection do currently manifest as fruit of an indissociable junction between culture and nature, what makes them not exclusively instinctive, but rather incorporated to a conscious net of thoughts, functioning according to current cultural context. It is intended that conclusions reached in the present work help weaken what is known as natureculture dualism, thus defining an evolutive process as not solely biological nor solely cultural. The process of psychological evolution and its behavioral products are therefore simultaneously biological and cultural, in an intrinsically connected way.