Due to females’ higher obligatory parental investment in gestation and lactation compared with males in the case of mammals, including humans (Bateman 1948), females tend to provide more parental care and devote less energy to mating. This tendency, in turn, affects the operational sex ratio (Clutton-Brock 2007), skewing it toward males. Therefore, females can exert their preferences in mate selection, choosing males with a higher social status and more resources thus able to provide more parental investment (Trivers 1972). In humans, it has been found that women are choosier compared to men (Buss 1989, Buss and Schmitt 1993, Buss and Schmitt 2019) and that there is more significant variance in men’s reproductive outcomes as a result of sexual selection (Wilder et al. 2004, Betzig 2012).
Social Status Influences Mating and Reproductive Success
As higher social status is accompanied by more resources being available for rearing offspring and women thus would be expected to prefer higher social status men as their mates (Trivers 1972), men with higher social status should in theory have greater mating success and reproductive success (i.e., more offspring) than men with lower social status. Empirical evidence has consistently shown that, in pre-industrial societies, higher-social status men achieved greater reproductive success (Mealey 1985, Clark and Hamilton 2006, Hu 2020). However, in modern societies, the association between social status and reproductive outcomes is less clear. Some studies have found a null (Freedman and Thornton 1982, Perusse 1993) or negative relationship (Vining 1986) between social status and a man’s number of offspring, while others have found a positive relationship (Hopcroft 2006, Fieder and Huber 2007, Hopcroft 2020, Hopcroft 2021). What is worth noting is that although there is no positive relationship between social status and the number of offspring, Perusse (1993) found evidence suggesting that higher social status men had greater potential fertility — that is, higher copulation frequency. Fieder and Huber (2007) found that income was positively associated with reproductive success for men, mainly because they could reduce the risk of childlessness; after excluding men who had no children, the positive association between social status and reproductive outcomes for men became non-significant. Similar relationships between social status and bachelorhood, as well as childlessness, were found in contemporary Sweden (Kolk and Barclay 2021). Hu (2020) found that the positive relationship between men’s social status and the number of offspring in historical China became non-significant after controlling for the number of marriages.
Taken together, these results suggest that in the past, a high social status would have contributed to men’s reproductive success primarily because of mating success (i.e., a greater number of mates) rather than having more children per partner. This is also consistent with the fact that the maximum number of offspring a woman can have is limited. Note that this explanation does not contradict evolutionary thinking as no prediction of higher social status being associated with an increased desired number of children is made. Instead, it is more likely that the higher reproductive success of high-social status individuals is an indirect result of having more sexual partners (Forsberg and Tullberg 1995) and engaging in more copulations (Perusse 1993, Hopcroft 2006), which would naturally lead to more pregnancies and offspring in the evolutionary past, but not necessarily at present. Thus, in modern secular societies where contraceptives are widely used and (serial) monogamy is the norm, the social status-fertility link may be less strong for men. However, based on both theoretical predictions of women’s preference for higher social status men (Buss 1989) and previous research examining the social status-reproductive success association in men (Hopcroft 2006, Fieder and Huber 2007, Hopcroft 2021), we would still expect men with higher social status to have greater long-term mating success, leading to a decreased likelihood of having no children at all.
On the other hand, according to parental investment theory, reproductive outcomes tend to vary less for women at different points on the social status dimension compared with men, as lower status women are being selected against less than lower status men. That being said, women with a higher social status are more likely to have fewer children than their lower- social status counterparts in modern societies (Fieder and Huber 2007, Huber et al. 2010). From an evolutionary perspective, the lower fertility of higher social status women may partly originate from the interaction between the tendency for hypergamy and the norm of serial monogamy in modern societies. That is, women tend to marry partners who have a relatively higher social status compared with themselves, which is associated with mating and reproductive success for women (Bereczkei and Csanaky 1996). This tendency, however, could also result in spinsterhood at the top and bachelorhood at the bottom of society (Van Den Berghe 1960) in modern societies with a norm of serial monogamy. Research has shown that women with higher education and career prospects may be less desirable in the marriage market, which may result in lower marriage and fertility rates (Bertrand, Cortes, Olivetti, and Pan 2020, Hwang 2016). As more women enter and succeed in higher education and careers, obtaining higher social status, hypergamy is less and less achievable, especially for high social status women. Indeed, a recent population-based study revealed that educational hypergamy (i.e., the pattern in which husbands have a higher educational level than their wives) is ending, while hypogamy is increasing (Esteve et al. 2016). Research from China also indicates that the expansion of higher education enhances the tendency for educational homogamy among younger cohorts (Hui and Qian 2016). Therefore, higher social status women may have lower mating success leading to decreased reproductive success (for opposing evidence in recent Western cohorts, see Budig and Lim 2016, Torr 2011).
Though women’s fertility along the social status dimension can be influenced by evolutionary logic, other important factors have been proposed and studied. Firstly, pursuing higher education and participating in the labour market tends to delay the age of a woman's first marriage (Ikamari 2005), thus postponing reproduction (Mills et al. 2011). Moreover, the anticipation and planning of marriage can also impact women's education levels. Research shows that in specific settings (e.g., rural India), the perceived incompatibility between higher education and preferred age of marriage in women is more significant, which impacts the parents’ decision towards their daughter’s education (Maertens 2013). Secondly, the cost of rearing a child increases as social status rises. Borg (1989) found that after controlling for the estimated net cost of a child, calculated by the sum of a child’s cost and benefits and the mother’s opportunity cost, the negative relationship between income and fertility became positive. Thirdly, evidence suggests that childbirth negatively affects women’s employment and income (Hofferth and Curtin 2006, Takeuchi and Otani 2007, Ejrnæs and Kunze 2013), suggesting a bi-directional relationship. All of these point to the complexity of the mechanisms involved.
Taken together, we hypothesized higher social status to be associated with greater mating success (staying in a marriage) and reproductive success for men but less mating success and reproductive success for women. More specifically, we hypothesized that:
Higher social status increases the likelihood of being married for men but decreases it for women (H1).
Among those who were or have been in a marriage, higher social status decreases the likelihood of marriage disruption for men but increases it for women (H2).
Higher social status increases reproductive success for men but decreases it for women (H3).
The Association of Social Status Difference between Spouses and Their Mating and Reproduction
Besides influencing men and reproductive outcomes via mating success, the tendency for hypergamy can also influence the reproductive outcomes among those who have entered a marriage. That is, the social status difference between partners may also impact reproductive outcomes. Women who marry higher social status men and men who choose younger women as mates have significantly more surviving children than those who pursue alternative mating strategies (Bereczkei and Csanaky 1996). A recent study from China found that women’s relatively higher social status compared to their partners negatively predicted the intention of having a second child (Qian and Jin 2018). Indirect evidence from marital quality also suggests that the social status difference between partners is important. Women who have higher relative social status compared with their male partner were more likely to suffer from domestic violence (Kaukinen 2004, Kayaoğlu 2020), which from an evolutionary point of view, can be conceptualized as a male’s mate retention tactic (Shackelford et al. 2005, Kaighobadi et al. 2009). Moreover, women who have a relatively higher social status compared with their partner were more likely to separate and divorce (Heckert et al. 1998, Liu and Vikat 2007), though in recent US cohorts, this relationship seems to no longer hold (Schwartz and Gonalons-Pons 2016; Schwartz and Han 2014). Therefore, we hypothesized that among first-time married couples, the higher the relative social status of the husband compared with the wife, the greater will be their reproductive success (H4). We restricted this hypothesis to first-time married couples because the current dataset neither recorded individuals’ fertility by marriage nor contained social status information about the respondents’ ex-partners. Therefore, using the relative social status of the current partners to predict fertility through multiple marriages is theoretically problematic.
Age at first marriage can serve as an indicator of mating success in humans. Using historical data, Telford (1992) showed that higher social status is associated with earlier marriage for sons in China. As there is a trade-off between spending time searching for high-value partners and securing an available mate to reproduce with, men who have a relatively higher social status than their future partner may enter into marriage earlier than those not in this advantageous position. We hypothesized that for women, however, the tendency for hypergamy predicts that higher social status women may face more difficulty finding satisfactory partners, increasing the marriage age (H5). Evolutionary psychology also predicts that compared with women, men tend to prefer younger mates who are more fecund (Kenrick and Keefe 1992). However, men's reproductive function is less influenced by ageing than women, and wealth tends to accumulate with age. Therefore, men may make trade-offs between their partners' social status and age, but not women. We hypothesized that men who marry women of relatively lower social status than themselves have younger wives than those men who marry up. In comparison, women who marry men of relatively lower social status than themselves do not have younger husbands than those who marry up (H6). Note that in both hypotheses 5 and 6, we only propose the negative relationships due to trade-offs and do not state that the social status difference causes changes in the age of marriage.
The relationships hypothesized in H1-3 have been partially examined and supported in previous studies (Hopcroft 2006, Fieder and Huber 2007, Hopcroft 2021) using WEIRD (Henrich et al., 2010) data. Thus, the corresponding analyses in the current study will be conceptual replications using different statistical methods and data (see Methods section). However, examining how the relative social status between married couples affects their mating and marriage outcomes (H4-6) has been studied less directly and, therefore, represents a relatively novel contribution to the literature.
Social Status and Reproduction in China
In China, the fertility rate has been declining due to social and economic development and the state’s policy on birth control (Lavely and Freedman 1990, Cai 2010, Piotrowski and Tong 2016) dating from the 1970s (Wang 2012). Thus, a popular conception of fertility decline in China is that the family planning policy mainly drives it. However, research has suggested that social and economic development play a more critical role, like other countries that have experienced a demographic transition (Cai 2010). Furthermore, previous research on social status and fertility in China has only focused on women’s fertility and found that education was negatively associated with fertility and childbearing intentions (Zheng et al. 2016), consistent with findings from other countries (Fieder and Huber 2007, Huber et al. 2010). Therefore, it is reasonable to assume that despite being influenced by a strict policy, Chinese data remains suitable for examining the social status-fertility link.
Moreover, it is difficult, if not impossible, to find a modern industrialized state where the natural fertility of humans may be studied without the influence of any societal structures. As mentioned above, other countries have influenced fertility patterns by social policies (Jalovaara et al. 2019), albeit in the opposite direction. Analyses based on these data have been published and considered as evidence either for or against evolutionary hypotheses. Therefore, results from China are not just acceptable but essential for developing an unbiased understanding of the hypothesized social status-fertility link. However, at this moment, less is known about how social status impacts men’s marriageability and fertility in China. Thus, whether one of the central hypotheses in evolutionary psychology – higher social status positively influences mating and reproductive success for men – still holds in China is unknown and demands investigation.