Mate Choice, Marital Success, and Reproduction in a Modern Society

Transcription

1 ELSEVIER Mate Choice, Marital Success, and Reproduction in a Modern Society Tamas Bereczkei and Andras Csanaky Institute of Behavioral Sciences, Medical University of Pdcs, Hungary A series of eight predictions concerning human mating was tested on interviews with 1057 female and 774 male Hungarians, who were close to completed fertility. Mating preferences as predicted from the evolutionary explanations are reflected in actual mate choice. Males, more than females, prefer and choose younger mates at marriage, whereas females tend to marry higher educated mates. The reproductive consequences of mate choice are adaptive: females who marry higher status mates and males who choose younger mates have signif'~antly more surviving chadren than those following alternative mating strategies. This link between muting preferences and reproductive output may be mediated by marital success as a proximate mechanism. Couples whose wives are younger and/or less educated and whose husbands are older and/or more educated stay together for a longer period of time than other couples. Similarly, the age and educational differences between spouses are associated with marriage quality. Finally, homogamy is found as a widespread form of mate choice that proved to be almost as reproductively successhd a strategy as hypergamy. We argue that females switch between homogamy and hypergamy and vice versa, depending on the particular social circumstance. KEY WORDS: Mating strategies; Hypergamy; Homogamy; Marital success. i n humans, like in other animals, certain kinds of mate selection and competition are expected to confer a fitness advantage compared to others. Evolution has endowed humans with a discriminating desire for certain mates. Obviously, being involved in special forms of marriage and childbirth, we tend to obey cultural expectations and norms through which we increase our self-esteem. Humans wonder if accomplishing cultural goals lead to high inclusive fitness (Irons 1979). In evolutionary terms, then, relevant questions are: Which forms and styles of marriage promote male and female reproductive Received December 12, 1994; revised July 28, Address reprint requests and correspondence to: Tamas Bereczkei, Institute of Behavioral Sciences, Medical University of P6cs, P6cs 7624, Szigeti u. 12, Hungary. Ethology and Sociobiology 17:17-35 (1996) Elsevier Science Inc., Avenue of the Americas, New York, NY /96/$15.00 SSDI (95)

2 18 T. Bereczkei and A. Csanaky success? How does one's own and his or her mate's income, education, employment, and other socioeconomic factors influence the individual capacity of spreading genes? Due to the initial inequalities between the sexes in parental investment, mean differences are expected to exist between women and men, in terms of which traits are considered attractive (Williams 1975). In our species, although male parental investment is, like in other mammals, less than that of the female, it is substantial in contrast to many other species. Women, therefore, are expected to secure maximal resources monopolized by men that are to be invested in children. They may be expected to value characteristics in potential mates that show possession or likely acquisition of resources (Buss 1987; Symons 1979). Some empirical studies have established certain attributes that females want to be present among their potential mates or marriage partner. Females, more so than males, prefer criteria of wealth and status that, in fact, are closely linked to resource acquisition (Buss and Barnes 1986; Townsend and Levy 1990). Cues like good earning capacity, ambition, good financial prospect, and high-status profession appear to be highly valued by them all over the world (Buss 1989, 1990; Feingold 1992). Males, on the other hand, are expected to compete with each other to pair with females whose reproductive value is high. They prefer female characteristics such as physical attractiveness, youth, and a good physical condition (Buss 1987; Symons 1979; Thornhill and Thornhill 1983). Males have been selected for using these cues in order to secure mates with high fertility and reproductive capacity. Indeed, various studies- including cross-cultural ones- have shown that males, more so than females, when valuing potential mates, place great importance on the criteria of being good-looking and attractive (Buss 1989, 1990; Feingold 1992; Townsend and Levy 1990). Other studies using various methods have revealed similar characteristics of mate choice. Men prefer females with an attractive physical appearance without regard to their status. Conversely, females find males with a poor physical appearance more attractive when their status as shown by their ornamentation was considered high (Hill et al. 1987). These sex differences are also found among mate-retention tactics during the crisis of pair bonding: Men use a display of resources more often than women, who use good appearance and the threat of infidelity to gain their mate back (Buss 1988). Intrasexual competitive behavior, classified into 26 various tactics, proved to be ultimately related to attracting potential males, and it confirmed the predicted differences in mate choice between human males and females (Waiters and Crawford 1994). Using "lonely heart" advertisements, additional support was found for the hypotheses that women prefer mates possessing traits associated with both the willingness and the ability to provide resources (in the form of time, emotion, money, and status) in a relationship, while men rather value physical attractiveness and younger age (Thiessen et al. 1993; Greenlees and McGrew 1994). Recently, Buss found that mate preferences that men and women express for obtaining short-term mates differ from those expressed for obtaining long-term mates, although the main differences between the sexes remained the same (Buss and Schmitt 1993).

3 Mate Choice, Marital Success, and Reproduction 19 Actual Mate Choice and Reproductive Success The above studies have shown that males and females use different criteria for mate choice. From an evolutionary perspective, however, two important questions have remained unanswered. First, we should examine whether sex differences in mate selection affect actual mate choice. It is well known that actual mate choices are determined by many factors, including opportunity, personal characteristics, parental influences, and so forth, that undoubtedly modify mate preferences (Whyte 1990). Nevertheless, preferences are expected to represent one of the main causal forces affecting actual mating decisions. Unless mates are actually chosen according to the stated preferences, these preferences are irrelevant to the evolutionary approach. Therefore, we should go beyond the scope of desires concerning potential mates and their values, and instead investigate the actual mating strategies. Second, because the bottom line of Darwinian studies is the genetic representation individuals have throughout their lifetime, it is crucial to learn whether the predicted male and female choice is associated with a greater reproductive success. In other words, do females choosing males with more resources and males choosing attractive females have more surviving children than those who follow alternative strategies? A few studies have revealed a link between mating preferences and actual mating choices in sexual attractiveness and age. Age differences preferred by mates in the questionnaire studies are a good predictor of actual age differences between married spouses. In a study of 37 samples worldwide, the men on average were 2.99 years older than their wives-approximatively the average of the age difference preferred by males and females (Buss 1989). Additionally, physically attractive females appear to marry males of a high occupational status. The assessment of women's attractiveness and their husbands' occupational position are positively correlated with each other (Elder 1969; Taylor and Glenn 1976). In other words, males possessing resources and females with an attractive appearance tend to search for each other in the "marriage market." In a more re- Cent study, for males, partner acquisition was found to correlate strongly with social status, whereas, for females, it inversely correlated with age (P6russe 1994). These studies, however, carry certain methodological constraints. First, the occupational status of the women was not measured independently of that of the males. This failure imposes a difficulty in calculating the degree of marrying up. Females do not simply tend to marry males of high status and prestige, but rather males with a higher status and prestige than their own. This is particularly true for financially and occupationally successful women: They show the same preferences for mates as other women do. They appear to value even more resources and higher status than they themselves possess (Townsend 1989). Yet, females who expect to find investing males tend to suppress their resources and appearance of competence in order to emphasize their need for investment (Cashdan 1993). Second, other preferred criteria of mate selection, such as income, education, wealth, and so forth, have still not been proved to affect actual mate choice. Each of these should be measured in both marriage partners in order to better understand actual mate choice.

4 20 T. Bereczkei and A. Csanaky The other crucial point is to investigate the relationship between the psychological preferences in mate choice and reproductive success. Do males who choose younger and attractive females and females who choose males with greater resources in fact have more surviving children than those who follow alternative strategies? Several studies in preindustrial societies have shown that certain types of mate choice are strongly associated with fertility. Thus, Kipsigis women's attractiveness such as age and physical condition measured by bride price was found to be positively correlated with their lifetime reproductive success (Borgerhoff Mulder 1988). In the Krumhorn population (Germany, 17th-18th century), the younger the women were when they married and the wealthier the men whom they married, the more surviving children they had (Voland and Engel 1990). In modern societies, however, no reliable data about the relationship between mating preferences and reproductive success are known to us. According to some authors, mating preferences were adaptive only in our evolutionary past, and they are not expected to be relevant to reproductive success in industrial societies anymore (Tooby and Cosmides 1990; Symons 1989). Others claim that psychological capacities underlying mate choice, like other evolved learning rules, enable us to adaptively track the environment even in modern societies (Alexander 1990; Turke 1990). If this is true, certain kinds of recent marriages would tend to produce more children than others, that is, as predicted by mate-selection theory. Given that predispositions to choose mates in order to increase reproductive success are evolved components of human behavior, the following predictions can be made: Prediction L Males would prefer their marriage partner to be younger, whereas females would prefer their mates to be older. Females tend to marry up in that they choose mates with a higher education, occupational status, and income. Prediction 2. These differences in actual mate choice will be mirrored in reproductive differences. Those men who marry younger women and those women who marry men with a higher status will have more children than others who engage in alternative choices. Prediction 3. As males become older, they are expected to choose relatively younger females. In other words, as men get older, the relative age difference between them and their spouses increases. Prediction 4. When they remarry, the age difference between men and their spouses will be increased. In other words, men who remarry choose a relatively younger mate than those men who married only once. Prediction 5. Consequently, for males, but not for females, the number of divorces and remarriages is positively associated with the number of children.

5 Mate Choice, Marital Success, and Reproduction 21 Homogamy and Hypergamy Natural selection has endowed humans with a particularly fine-tuned set of mate preferences. Not only differences but also similarities in age and status between pairs may affect mate choice. In industrial societies, positive correlations have been found between spouses in anthropometric characteristics, personality traits, and many kinds of sociocultural indices (Epstein and Guttman 1984). Marriage partners tend to resemble each other in characteristics like age, socioeconomic status, ethnic background, physical attractiveness, level of education, intelligence, social attitudes, and political orientation. It has been found that homogamy contributes to marital stability as well as to the enhancement of the number of surviving children (Mascie-Taylor 1988; Thiessen and Gregg 1980). Evolved homotypic preferences are suggested to increase genetic relatedness between mates, promoting cooperation and enhancing inclusive fitness (Thiessen and Gregg 1980). Genetic similarity theory, an extension of kin-selection theory, suggests that individuals can detect similar qualities in others in order to spread their shared genes through altruism that they develop toward each other (Rushton et al. 1984). Using blood antigen analyses, the degree of genetic similarity between marriage partners has been found to he greater than between individuais randomly paired from the population (Rushton, 1988). Another study revealed that the larger the heritability of traits was, the more positive the assortative mating was for these traits (Rushton and Nicholson 1988; Russell et al. 1985). Homogamy and hypergamy as adaptive social preferences seem to have distinct evolutionary roots. They have probably been shaped by different selectionary processes and, as a consequence, they achieve by different means the same basic function: the enhancement of inclusive fitness. Although the proximate mechanisms of mate choice are largely unknown, they are likely to be different for homogamy and hypergamy. One mechanism is to estimate the resource-holding potential of the mate, and the other is to recognize genetically similar traits in the mate (Buss 1992; Rushton 1989). We assume that both hypergamy and homogamy are operant under particular circumstances; one is beneficial in a given social environment, and the other is beneficial in a different environment. Females are expected to follow a trade-off between these strategies. In highly stratified societies, where men monopolize resources, hypergamy is a common practice for women because marrying up enhances the chance for their children's survival (Boone 1988; Dickeman 1981; Voland and Engel 1990). However, when a society is not highly stratified in terms of wealth and status, and access to resources is allowed for females as well, homogamy is expected to become prevalent. This is because fewer high-status males are available for females to choose from, and more similarities than differences exist between potential couples in terms of education, occupation, income, and so forth. Furthermore, homogamy as an adaptive feature of human mate choice is expected to be linked to a reproductive output that is above average. Given the former conditions, the following predictions are made:

6 22 T. Bereczkei and A. Csanaky Prediction 6. Even under more or less egalitarian circumstances-as exist in modern industrial states - only a minority of the population will engage in a marriage where males are younger and possess a lower status. The majority of marriages are either hypergamous or homogamous. Prediction 7. Females who choose mates with the same social status and the same age will have more children than women who marry mates with lower status and/or younger mates. Marital Success Both males and females are likely to be chosen as a marriage partner according to evolved mate preferences. Furthermore, those women who choose men with a higher status and men who marry younger, physically attractive women should have more children than others who follow alternative strategies. We assume that the link between adaptive mate preferences and reproductive success is stability and happiness of marriage. Mating criteria, having been shaped by natural selection, give rise to a successful marriage, which, in turn, expresses itself in enhanced inclusive fitness. In other words, at a proximate level, a happy and successful marriage mediates between psychological preferences and reproductive output. What makes the difference between a good and bad marriage? Conventionally, the literature on this topic distinguishes between marital stability and marriage quality (Whyte 1990). Marital stability refers to the duration of a marriage, that is, how long the couples stay together without a divorce. Marriage quality, on the other hand, refers to a set of features of an existing marriage, such as affection, communication between couples, satisfaction, conflicts, spouse abuse, and so forth. Prediction 8. Those marriages will be more successful than others in terms of both marital stability and marriage quality where the females are younger and the males possess higher status. These couples will stay together for a longer time and form a more satisfactory and happy bond. Several studies have revealed that differences between spouses in physical attractiveness and status are associated with marital success. In one study, a moderate husband dominance (decision-making power) and a moderately greater attractiveness of the wife was found to be consistent with marital satisfaction (Weisfield et al. 1992). In another research from the United States, divorce proved to occur more often when the wife's income exceeded her husband's (Booth and Edwards 1985). Additionally, marital dissatisfaction and wife abuse are more frequently found when the wife is higher educated than the husband (Hornung et al. 1981). Homogamy also tends to increase the stability and satisfaction of marriage (Bentler and Newcomb 1978). Only slight discrepancies, if any, between spouses in income, education, parental wealth, and intelligence have been found to correlate with marital satisfaction (Weisfield et al. 1992).

7 Mate Choice, Marital Success, and Reproduction 23 METHOD Our present study was part of a more comprehensive investigation carried out by our research center (Institution of Behavioral Sciences, Medical University of P6cs) between 1988 and 1989 (Tahin et al. 1993). The original survey aimed at assessing the recent state of health in a large area, in Baranya County (southwest part of Hungary). It encompassed the capital of that county (P~cs), two other towns, and 37 villages. It aimed at studying the demographical situation, occupational distribution, personal life style, habits concerning health care, diseases, alcohol and drug addiction, and many other topics. Two-sitting questionnaires were used to collect 2776 variables about 3777 persons. Our sample was representative of the larger population in terms of age, sex, occupation, and settlement. Each of the participants was interviewed personally by a collaborator who was not informed about the purpose of the study. This procedure took about four hours, including resting periods. In our present research, females below 35 years of age and males below 40 years of age were omitted from the original sample. The resulting population contained individuals who were close to the state of completed fertility. Indeed, in Hungary, according to the Demographical Annual Review (1989), females over 35 give birth to only 5.65 T0 of all children, and males over 40 sired o. Therefore, the total number of participants was limited to 1831 persons, that is, 1057 females and 774 males. A total of 881 ( ) persons lived in P6cs, 349 (19.0%) in the two towns, and 601 (32.907o) in the villages. The overwhelming majority of the subjects were currently married (males: 82.3o70 married, 3.0o70 widowed, 6.3o70 divorced; females: married, 8.4% widowed, divorced), and, according to the Hungarian laws at that time, almost all females and males of working age were employed full time (Table 1). In fact, some of the women were on paid marital leave, but they kept their job and could- actually they had to- return to work after the maximum three years' absence per child. The distribution of education and occupation in our sample were representative of the population of that region. To enable a study of behavioral strategies from an evolutionary point of view, the following variables were taken: marital status, age at marriage, educa- Table 1. Male and Female Employment Status Male Female Employment status Frequency Percent Frequency Percent Employed Not-employed Employed, but on paid maternity leave Pensioner On sick pay Disabled Homemaker Others

8 24 T. Bereczkei and A. Csanaky tion, age and educational differences between married couples, the number of living children, marital success and stability, frequency of divorce, and of remarriage. All the variables were detected in the recent or-in the cases of widows and divorcees-last marriages. The distribution of both age and educational differences between married couples was analyzed, and reproductive success (the number of surviving children) was measured as a function of these differences. In estimating the degree of marriage quality, six questions had to be answered by participants. We used a 5-point scale from "not at all" to "yes, very much," and from "almost never" to "very frequently." In order to assess marital success associated with age and educational differences between spouses, only the extreme values of that scale were used (Table 7). The data were analysed with t-test for significance of age and educational differences. Because the number of children is not normally distributed (this variable shows skewness with more couples without children and a long tail for those Table 2. Age Difference Between Married Couples at Marriage Age difference (years) Frequency Percent Note: -female is older; + male is older.

9 Mate Choice, Marital Success, and Reproduction 25 Table 3. Age Difference Between Married Couples at Marriage by Age Groups Male Female Mean age Mean age difference difference Age groups Cases (years) Std. Dev. Cases (years) Std. Dev p =.0297 p =.0032 with many children), Mann-Whitney Two-Sample Test was used for comparing reproductive success. Because education is a categorical variable with eight values, the relationship between income and education was analyzed with Spearman's Coefficient of Rank Correlation. RESULTS Age Differences and Reproduction As Table 2 shows, only of women were older than their husbands. Among couples whose age difference was two years, men were found to be older in 6 times more marriages than women. Of those couples with 4 and 8 years' age differences, males were older in 24 and 27 times more marriages, respectively, than women. Males preferred mates who are, on average, 3.7 years younger than they are, whereas females preferred mates who are, on average, 3.39 years older. The mean age difference was 3.56 years. Comparing the absolute values of the actual age at marriage, similar trends exist. Males showed a preferred age of marriage at 24.08, and females at This asymmetry between the sexes seems to be stable across different age groups; the age difference at marriage does not change much, either for males and females (Table 3). This constancy in age difference between married couples over the decades suggests a deep and stable individual bias, which has occurred Table 4. Age Difference Between Married Couples by Age at Marriage Male Female Mean age Mean age Age at difference difference marriage Cases (years) Std. Dev. Cases (years) Std. Dev. ~< > p =.0000 p =.0000

10 26 T. Bereczkei and A. Csanaky Table 5. Age Difference by Remarriage Mean age difference (years) Male Female Cases Std. Dev. Std. Dev. Male Female First marriage Remarriage p =.0000 p =.0374 in spite of the profound social and political changes in Hungarian history during the past fifty years. However, if we relate this age difference to absolute age at marriage, we get another picture. As men get older, they choose relatively younger mates. The later a man gets married, the larger the age difference between him and his spouse. Conversely, age difference-with one exception-decreases as women are older at the age of marriage (Table 4). Similarly, in males there is an increasing age difference between them and their mates as they remarry, whereas remarrying females appeared to follow a reverse strategy (Table 5). In fact, males prefer and actually choose females displaying cues, such as younger age, that are associated with a higher reproductive capacity. As also predicted, this adaptive preferences gives rise to an increased genetic fitness. The number of those surviving children were counted who were born to marriages where the age differences between spouses were calculated. As shown in Figure 1, men marrying younger women have significantly more common children on average than men whose wives are older (1.82 vs. 1.43). Also, men who marry more than once have on average more children than men who married only once, although this difference does not reach significance (1.93 vs. 1.74). This, in part, FIGURE 1. Age difference between married couples at marriage and fertility.!-! [] Ivlale 1.~18 [] Female ~iiii~i~iii~iiiii~i I Younom" husbmxl No ~ dil~mn~ p (males) < 0.05 Ol~w hu~m~

11 Mate Choice, Marital Success, and Reproduction 27 may be due to the fact that male remarriage is correlated with an increased age difference between sexes at marriage. At the same time, when females remarry, the number of their children appears not to be different from that of females who marry only once (1.91 vs. 1.92). Female reproductive capacity is clearly associated with young age. However, the reproductive difference is much smaller when hypergamous and homogamous women's mates are compared. As predicted, assortative mating concerning age is a reproductively successful strategy compared to marriages in which the women are older than their mates. Indeed, men marrying women of the same age have a similar reproductive output as if they married younger mates (Figure 1). Female reproductive success is also higher when the husband is older (even though this correlation is not so strong as on the male side). Although this result was not predicted, it seems reasonable because the number of children was measured in marriages where the age differences between spouses were calculated. A husband with a younger wife has a wife with an older husband, and they have common children. However, a certain asymmetry between female and male reproductive success has been found, and this may be due to the fact that both female and male populations were randomly selected and separately examined. None of the males were married to any of the females in our sample. Education and Reproduction Education was used as a reliable measure strongly associated with socioeconomic status; various studies have revealed that the higher the education, the higher the personal and family income, and the higher the occupational position for FIGURE 2. 2 Difference in education between married couples and fertility. 1,8 J 1.64 i 1.4 More educated wife No d ~ Mote educated ~ d p (females) < 0.05

12 28 T. Bereczkei and A. Csanaky Table 6. Difference in Education Between Married Couples Male Female Difference in education Cases Frequency Cases Frequency Note: - : more-educated female; + : more-educated male. Scale of Education: I. 0; II. 1-4 years completed; III. 5-7 in elementary school; IV. 8; V. School of skilled workers; VI. Secondary school without maturity; VII. Secondary school with maturity; VIII. Higher school. both males and females (Bourdieu and Passeron 1977). In our sample, these correlations appeared clearly to be present between education and personal income (0.38), education and family income (0.37), and education and occupational status (0.76). Education was classified into eight groups, from which the differences between spouses were established. Education proved to have a large effect on mate choice; the majority of females preferred mates with the same or higher educational level (Table 6). Only of women choose men of lower education and they give birth to significantly less children than women marrying more educated FIGURE 3. Age differences between married couples and marital stability by age group. / / / / ~ 35 'IS f - f29.1 ~.~ ~'~ -o- older ~ older wile,o 15 J., '1"~,.,,,,, I~ I "~3 J p< A A~ moun

13 Mate Choice, Marital Success, and Reproduction / 15 p< FIGURE 4. group. q J Age group Educational differences between married couples and marital stability by age men (1.61 vs. 1.90) (Figure 2). On average, the hypergamous women's reproductive output was higher by 20% over those who chose men of a lower socioeconomic status than their own. As also predicted, assortative mating concerning education is reproductively nearly as successful a strategy as marrying up: The reproductive consequences of homogamy are more similar to that of hypergamy than that of hypogamy. Marital Success We examined how marital stability might be connected to age and educational differences between cohabiting spouses. Couples where the husband was younger and less educated divorced on average more frequently than couples where the husband was older and more educated (for age differences: 28.4% vs. 13.0%; for educational differences: 26.2% vs. 16.9%). Those married couples where the husband was younger stayed together on average for years, whereas couples where the wife is younger have stayed together on average for years. Educational differences have a similar effect on the duration of marriage. Higher educated husbands with less educated wives have lived together on average years, and couples with reversed educational differences have stayed together for years. All of these differences were highly significant (p < 0.01). For the purpose of correcting for age at marriage and age of partners at interview, marital stability was analyzed by age group. Although the differences proved to be smaller, it is still true that in every age group couples where the husband was older and more educated stayed together for a longer period of time than couples with a reversed difference. The differences in duration of marriage- with two exceptions- were statistically significant (Figures 3 and 4).

14 30 T. Bereczkei and A. Csanaky In summary, couples with older, higher educated husbands and younger, less educated wives have been living together, on average, for a significantly longer period of time than other couples do. Respondents were also asked to what degree they were satisfied with their marriage and their mates, and whether they judged their pair bonds to be steady and successful or insecure and bad. In order to obtain the necessary information, six different questions were asked about marriage quality. We kept the extreme values of the answers on both sides (very much, very frequently, and not at all, almost never, etc.) and omitted the mean values (fairly, well, several times, etc.). We wondered whether age and educational differences between mates were associated with marital success. Those who were rather satisfied with their mates- that is, who got along well with each other, felt themselves happily married, had no severe problems, had no severe disagreements, and did not want to change their partner or marital life-lived in marriages where the measured differences in age and education (in favor of the husband) proved to be larger than those between spouses of unsuccessful marriage (Table 7). These differences varied greatly; some were smaller, others were larger. The age differences- with two exceptions- were statistically significant, whereas the educational differences Table 7. Marriage Quality by the Difference Between Marriage Couples in Age and Education Age you happy in your marriage? * Yes, very much 3.92 Not really or not at all 2.99 Are you satisfied with your partner? * Yes, very much 4.05 Not really or not at all 2.77 How do you get on with your partner? * Very well 3.79 Not well or not at all 2.87 Do you have severe problems in your marriage? No 3.62 Yes, many 2.71 How frequent do you have disagreements with your partner? Rarely or almost never 3.68 Frequently or very frequently 2.92 Do you want to change something in your marriage? * No 3.63 Yes, a lot of things 2.35 * p <.05. Mean age Mean difference difference Std. Dev. Cases in education Std. Dev. Cases , I O

15 Mate Choice, Marital Success, and Reproduction 31 were not. However, all the measured differences were in the predicted direction. Unfortunately, the method we used did not prove to be suitable for distinguishing any real differences between homogamous and heterogamous marriage in terms of marriage quality. DISCUSSION Age, Education, and Reproduction In summary, a majority of males preferred and chose younger mates at marriage and these males sired more children than males marrying older mates. As males get older, they choose relatively younger mates. When they remarry, the age difference between them and their wives is increasing. Males who marry more than once have on average more children than men who marry only once, whereas remarrying females follow a reversed strategy. A majority of females tended to marry mates possessing a higher educational level that is linked to resource acquisition, and these females had significantly more children when married to higher status mates. These relationships are likely to hold for other components of socioeconomic status: income and occupational position. Homogamy and Hypergamy Hypergamy- marriage between older, higher status men and younger, lower status women-is a prevalent form of mate choice that, additionally, involves a reproductive advantage for both males and females. Strikingly, however, it turned out that homogamy plays an important role in mate choice; a large proportion of females prefer mates of the same age and education instead of marrying mates with higher age and education. This preference may be due to several factors. First, in modern societies, people most often meet and interact with others of similar traits because of proximity effects (residing in the same neighborhood, attending the same schools, sharing common work environments, etc.). Thus, many men with high status may pair off with women with high status, even if they are more attracted to younger, lower status women (Feingold 1992). Second, marriage between mates with similar characteristics may well express an adaptive decision. Homogamy is, like hypergamy, an evolved strategy that has contributed to the enhancement of female inclusive fitness. Indeed, women marrying men of the same education and same age have a reproductive success close to those who marry higher educated and older men (Figures 1 and 2). Third, certain classes of individuals may be more constrained to practice homogamy than others. Specifically, higher educated women have less chance of marrying up because of the relative lack of suitable husbands. They tend to choose men of the same social status rather than those of a lower status. In contrast, men are less likely to prefer mates with a similar or higher status. In our sample, of women graduates had mates with the same education, and only

16 32 T. Bereezkei and A. Csanaky 30% chose husbands with a lower education. In contrast, only of men graduates proved to be homogamous, while the others had less educated wives. Unfortunately, the scale we used for measuring education was not sufficiently detailed to calculate the exact "downward" and "upward" movements in marriage. We do not know, for example, which percentage of males with a low education tend to marry even lower and which percentage of females with a high education tend to marry even higher. We suppose that using more finely tuned categories for the scale of education, the proportion of hypergamous women would increase. Although in Hungary there are not as many kinds and levels of higher education as in the United States, it remains the case that acquiring different diplomas may involve different levels of prestige. Human behavioral patterns, such as mating preferences, are often complex and depend on the particular pattern of social arrangement existing in a society. A basic message of the evolutionary approach to behavioral science is that behavior depends on the context: Individuals respond appropriately to the environmental challenges they'encounter. If the criteria of mate choice are facultatively expressed, prevailing conditions will determine the preferred traits of marriage partners. Homogamy and hypergamy are different behavioral strategies; both tend to enhance the individual reproductive success through different mechanisms of mate choice. Females seem to conduct a trade-off strategy between hypergamy and homogamy. It has been shown that in preindustrial societies, wealth and status, especially that of males, are positively associated with reproductive success. In highly stratified societies where resources can be transformed into reproductive success and women have no access to them, the majority of women are expected to prefer hypergamy to homogamy. Marrying up is an adaptive strategy for females and their relatives in this environment because it increases the chance of their children's survival. This study suggests that hypergamy, to some degree, has kept its selective value; women marrying up have more children than others. In modern societies, however, where no sharp status difference exists between sexes, women have a much lower possibility of hypergamy, and are therefore forced to choose a mate with a similar social and financial status. We assume that women living in contemporary societies tend to switch off from hypergamy to homogamy because of the relative shortage of higher status mates. As women have an increasingly higher chance to have access to resources and gain social influence, they well decreasingly find suitable husbands to whom they could marry up. Therefore, they have to find another kind of marriage. Without the possibility of marrying up, they have other options left to choose, among which, they prefer homogamy because of its reproductively beneficial character. In other words, females tend to marry up to higher status males only if these males are available. Therefore, women with low education and low occupational status tend to choose more privileged and educated men, whereas educated and socially more influential women are forced to follow homogamy. As we have seen in our sample, only a minority of the highest status women were willing to marry mates with a lower status, and these women's reproductive success proved to be lower than hypergamous women's.

17 Mate Choice, Marital Success, and Reproduction 33 Ultimate and Proximate Causation The fact that these strategies manifest themselves in modern societies indicates their biologically evolved character. That they produce reproductive differences in a predicted way, in turn, suggests that they are still adaptive in this novel environment. Their adaptive character could be explained in two distinct, but hopefully not mutually exclusive, ways. First, conditional strategies underlying mate choice were shaped during biological evolution that was able to track the changing environment (Irons 1979; Turke 1990). A flexible decision-making system can be responsible for increasing reproductive fitness in various environments. Second, natural selection has shaped special-purpose adaptive mechanisms during the Pleistocene, and the human psyche comprises various designs serving specific functions. Mate preferences are considered as genetically prescribed behavioral algorithms (Tooby and Cosmides 1990; Symons 1989). In this case, certain elements of social life related to mate choice must have remained unchanged in human evolutionary history. These elements must have been prevalent over a long period of time, that is, enough to enable natural selection to shape adaptive preferences. In order for the evolved mate preferences to be adaptive, even in modern society, the main social relations of mate choice must necessarily have remained the same. Thus, the evolved psychological design in a substantially unchanged social environment might produce the measured reproductive success in industrial society. What kind of social circumstances could have continued to exist since the ancient human communities to modern ones? We think that marriage may have very stable constituents that might remain mostly unchanged over a long period of time. The primary relationships between husband and wife (or wives) that determine the stability and success of marriage, such as economic and emotional bonds, interdependency, and mutual obligations and assistance, can be considered as universal human traits even though their expressions have varied from culture to culture. Regardless of the particular economic and cultural structure of a given society, then, biologically prescribed mate preferences may produce more stable and successful marriages, and this marital success is, in turn, expected to be transformed into reproductive success. Indeed, this study has revealed that couples where the husband was older and more educated stayed together for a longer period of time, were more satisfied with their marriage, and had significantly more surviving children than couples with reversed differences. Marital stability and quality is regarded as a kind of proximate mediator between psychological preferences and reproductive success. We think that these possible explanations do not exclude each other (Mac- Donald 1991); we may use conditional strategies in certain situations of mate choice and may follow specific psychological algorithms in other situations. Anyway, both of these approaches raise several questions. First, why do evolved mate preferences give rise to a successful marriage? What are the features of society-- that is, of course, products of the operations of our psychological mechanisms-- that make marriages between older, higher status men and younger, lower status women more durable and successful? Second, why do more stable and happier

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