The last couple of decades have seen a rise in prominence of both cultural and evolutionary approaches in psychology. At times, they have been unfairly and mistakenly seen as at odds with each other, with one approach emphasizing enormous human variability and the other emphasizing underlying human universals. Fincher & Thornhill (F&T) remind us that human evolution occurs within a social context that is responsive to changing local environments. Humans coevolve with other organisms in their environment – including various parasites. F&T offer an impressive theory that represents an able synthesis of evolutionary and cultural approaches, with far-ranging implications for a number of social-psychological phenomena.
One of the most exciting implications of the theory is its provision of a framework linking ecology to culture and social behavior (see Berry Reference Berry and Berkowitz1979; Triandis Reference Triandis1994). We believe that the parasite-stress theory may help illuminate cultural differences in relationships between men and women. While F&T point out (sect. 2.2, para. 4) the link between greater parasite stress, assortative sociality, and less freedom for women, they (understandably) do not theorize about why this is the case. We propose that the problem of mate selection, particularly within cultures of honor, can provide some explanation.
Perhaps one of the most fundamental dilemmas humans must confront is the optimal choice of a mate. The choice poses two competing risks. On one hand, as articulated by F&T, out-group members may introduce dangerous infectious diseases from novel foreign parasites. This may motivate the avoidance of coupling beyond the in-group. On the other hand, exclusive inbreeding runs the risk of congenital birth defects, and virtually every society has incest taboos to guard against this possibility (Brown Reference Brown1991). One solution is to be very selective about choosing partners outside of the immediate in-group, paying particular attention to cues that signal “purity.” Many societies have developed strict regulations regarding purity, along with great concern for purity as a central domain of morality (Rozin et al. Reference Rozin, Lowery, Imada and Haidt1999; Shweder et al. Reference Shweder, Much, Mahapatra, Park, Brandt and Rozin1997).
Behavioral rituals and attitudes that signal one's commitment to moral purity should be highly valued, particularly in environments of high parasite stress. These signals of moral purity should be doubly important in traditional cultures in which economic prosperity is highly linked to social reputation and forged with family alliances, as is the case in cultures of honor (Peristiany Reference Peristiany1965). In many such stratified societies, families can move up the social ladder through marriage alliances. It is almost always the case that with hypergamy (up-status marriage), it is women who marry into higher status families, and subsequently those women's families who stand to benefit (Ortner Reference Ortner1978). In this sense, purity (spiritual, moral, and sexual) is a women's value. As the anthropologist Jane Schneider (Reference Schneider1971) noted when discussing honor cultures of the Mediterranean, women are a “contested resource” and their comportment defines the honor of their social groups.
This established phenomenon takes on new meaning in light of F&T's theory, because in each of these marriage alliances, the male partner's family takes a risk in bringing a new member into their unit, and would not be inclined to do so without assurance of the conformity of the woman with all applicable norms. Therefore, women, who bear the responsibility of serving as ambassadors from their native unit, must be especially zealous in signaling their moral and physical purity.
Our recent work (Vandello et al. Reference Vandello, Hettinger and Cohen2011) provides evidence that norms for moral purity are stronger for females than males in virtually all nations globally, though there is also great variation in the extent to which female purity norms hold sway. As part of this research, we have developed an index measuring the extent to which cultures emphasize female purity (over and above emphasis on male purity), using cross-national data on things like sexual practices, preferences for virgins, and smoking and drinking rates of women relative to men. As an initial test of whether there might be a connection between F&T's notion of high parasite-stress environments and cultural concerns with female purity, we correlated our purity index with F&T's national ratings of non-zoonotic infectious disease prevalence. The association is quite strong, r=0.60, n=146, p<0.001, suggesting that in places where parasite stress is heightened, cultures emphasize female purity, perhaps as a way of ensuring women's “marketability” in a risky mating pool.
Also relevant is Schmitt's (Reference Schmitt2005) cross-cultural data on sociosexual mating orientations (monogamous versus promiscuous). Using his data on the extent to which male and female sociosexuality is restricted or unrestricted, non-zoonotic disease prevalence is associated with a more restricted female sociosexuality, r=0.38, n=45, p<0.01, but is not associated with male sociosexuality, r=0.11, n = 45, p=0.46, again suggesting stringent female purity norms may especially co-occur with environments of high parasite stress. While this may seem of questionable relevance for modern, progressive societies, we have gathered evidence that purity norms remain stronger for females than males among contemporary American college students (Hettinger & Vandello Reference Hettinger and Vandello2011), and women are policed more strictly than men to ensure against purity violations.
We acknowledge that this link between pathogen prevalence and female purity is quite speculative and awaits further testing, but we use it as an example of what we feel is a strength of F&T's theory – the possibility of linking ecological features to cultural norms and socio-psychological traits. More generally, F&T's theory may prove valuable in understanding the origins of cultures of honor, which are typically characterized by high degrees of suspicion, competition, and conflict between rival families and small clans who compete for strategic resources. It may be that in such cultures, where there is often very little sense of community beyond the family, and reciprocal hostility among groups is quite common (fostering in-group assortative sociality), pathogens are widespread.
The last couple of decades have seen a rise in prominence of both cultural and evolutionary approaches in psychology. At times, they have been unfairly and mistakenly seen as at odds with each other, with one approach emphasizing enormous human variability and the other emphasizing underlying human universals. Fincher & Thornhill (F&T) remind us that human evolution occurs within a social context that is responsive to changing local environments. Humans coevolve with other organisms in their environment – including various parasites. F&T offer an impressive theory that represents an able synthesis of evolutionary and cultural approaches, with far-ranging implications for a number of social-psychological phenomena.
One of the most exciting implications of the theory is its provision of a framework linking ecology to culture and social behavior (see Berry Reference Berry and Berkowitz1979; Triandis Reference Triandis1994). We believe that the parasite-stress theory may help illuminate cultural differences in relationships between men and women. While F&T point out (sect. 2.2, para. 4) the link between greater parasite stress, assortative sociality, and less freedom for women, they (understandably) do not theorize about why this is the case. We propose that the problem of mate selection, particularly within cultures of honor, can provide some explanation.
Perhaps one of the most fundamental dilemmas humans must confront is the optimal choice of a mate. The choice poses two competing risks. On one hand, as articulated by F&T, out-group members may introduce dangerous infectious diseases from novel foreign parasites. This may motivate the avoidance of coupling beyond the in-group. On the other hand, exclusive inbreeding runs the risk of congenital birth defects, and virtually every society has incest taboos to guard against this possibility (Brown Reference Brown1991). One solution is to be very selective about choosing partners outside of the immediate in-group, paying particular attention to cues that signal “purity.” Many societies have developed strict regulations regarding purity, along with great concern for purity as a central domain of morality (Rozin et al. Reference Rozin, Lowery, Imada and Haidt1999; Shweder et al. Reference Shweder, Much, Mahapatra, Park, Brandt and Rozin1997).
Behavioral rituals and attitudes that signal one's commitment to moral purity should be highly valued, particularly in environments of high parasite stress. These signals of moral purity should be doubly important in traditional cultures in which economic prosperity is highly linked to social reputation and forged with family alliances, as is the case in cultures of honor (Peristiany Reference Peristiany1965). In many such stratified societies, families can move up the social ladder through marriage alliances. It is almost always the case that with hypergamy (up-status marriage), it is women who marry into higher status families, and subsequently those women's families who stand to benefit (Ortner Reference Ortner1978). In this sense, purity (spiritual, moral, and sexual) is a women's value. As the anthropologist Jane Schneider (Reference Schneider1971) noted when discussing honor cultures of the Mediterranean, women are a “contested resource” and their comportment defines the honor of their social groups.
This established phenomenon takes on new meaning in light of F&T's theory, because in each of these marriage alliances, the male partner's family takes a risk in bringing a new member into their unit, and would not be inclined to do so without assurance of the conformity of the woman with all applicable norms. Therefore, women, who bear the responsibility of serving as ambassadors from their native unit, must be especially zealous in signaling their moral and physical purity.
Our recent work (Vandello et al. Reference Vandello, Hettinger and Cohen2011) provides evidence that norms for moral purity are stronger for females than males in virtually all nations globally, though there is also great variation in the extent to which female purity norms hold sway. As part of this research, we have developed an index measuring the extent to which cultures emphasize female purity (over and above emphasis on male purity), using cross-national data on things like sexual practices, preferences for virgins, and smoking and drinking rates of women relative to men. As an initial test of whether there might be a connection between F&T's notion of high parasite-stress environments and cultural concerns with female purity, we correlated our purity index with F&T's national ratings of non-zoonotic infectious disease prevalence. The association is quite strong, r=0.60, n=146, p<0.001, suggesting that in places where parasite stress is heightened, cultures emphasize female purity, perhaps as a way of ensuring women's “marketability” in a risky mating pool.
Also relevant is Schmitt's (Reference Schmitt2005) cross-cultural data on sociosexual mating orientations (monogamous versus promiscuous). Using his data on the extent to which male and female sociosexuality is restricted or unrestricted, non-zoonotic disease prevalence is associated with a more restricted female sociosexuality, r=0.38, n=45, p<0.01, but is not associated with male sociosexuality, r=0.11, n = 45, p=0.46, again suggesting stringent female purity norms may especially co-occur with environments of high parasite stress. While this may seem of questionable relevance for modern, progressive societies, we have gathered evidence that purity norms remain stronger for females than males among contemporary American college students (Hettinger & Vandello Reference Hettinger and Vandello2011), and women are policed more strictly than men to ensure against purity violations.
We acknowledge that this link between pathogen prevalence and female purity is quite speculative and awaits further testing, but we use it as an example of what we feel is a strength of F&T's theory – the possibility of linking ecological features to cultural norms and socio-psychological traits. More generally, F&T's theory may prove valuable in understanding the origins of cultures of honor, which are typically characterized by high degrees of suspicion, competition, and conflict between rival families and small clans who compete for strategic resources. It may be that in such cultures, where there is often very little sense of community beyond the family, and reciprocal hostility among groups is quite common (fostering in-group assortative sociality), pathogens are widespread.