University of California at Davis doctoral student, Ryan N. Schacht, supervised by Dr. Monique Borgerhoff Mulder, will undertake research on factors that affect the formation of human gender roles. The research is driven by recent theoretical and empirical work on gender that challenges conventional assumptions regarding male and female patterned behavior. Many of the assumptions about gender roles derive from research conducted primarily on Western populations. Therefore, this project focuses on a non-Western group undergoing rapid socioeconomic change.
The research will be conducted in two communities of Makushi people in the Rupununi region of Guyana. Research methods will include both semi-structured and structured interviewing. Data will be collected on Makushi culture and social organization; demographics and economics; and qualities that previous researchers have have found affect mate selection and marriage viability. These data will be compared across the two communities to test hypotheses derived from evolutionary theory on how features of the social arena, specifically the sex ratio of reproductive-aged individuals in the community and the socioeconomic factors that produce the sex ratio, affect sexual behavior, mate choosiness, parental investment, and conjugal bonds.
This work has broad theoretical significance because it will provide an empirical basis for arguments by gender theorists across the social sciences who call for a rejection of essentializing masculine or feminine natures as well as the focus on binary gender strategies. Additionally, the results of this research may inform policy for HIV prevention and mitigation of domestic violence. Funding this research also supports the education of a graduate student.
This research is driven by recent work on gender that challenges conventional assumptions regarding male and female patterned behavior as well as generalizations about human behavioral universals that have arisen from research conducted primarily on western populations. Recent studies in nonhumans reveal extraordinary flexibility of sex roles, both within and between the sexes. Despite these developments, somewhat rigid gender differences in human mating strategies remain a central focus of modern evolutionary psychology with men viewed as eager and indiscriminate in their sexual behavior and women as more coy and choosey. As a consequence, there is considerable concern amongst anthropologists that cultural influences in gender role formation are being overlooked and that we still have little evolutionary understanding of how variation in gender differentiated behavior arises from developmental factors and features of social structure and culture. In order to deal with these shortcomings, we designed a study to address one key feature of the social environment likely to influence mate choice behavior, the adult sex ratio (ASR). ASR theory is derived from the principle that sex roles are determined by the abundance (or shortage) of either sex. This is because the ASR of a population has a large effect on the available mating pool, or what can be thought of as a mating market. When one sex is in an oversupply, variations in the strategies of men and women will appear and cause variations in both mating preferences and behavior For the purposes of this study, eight villages composed of the Makushi Amerindian group in Guyana were studied. Makushi territory is located in southwestern Guyana, near the Brazilian border. The Makushi generally build their villages on the savanna and plant their farms in the nearby forests. They practice swidden horticulture and their staple crop is bitter cassava. Across Guyana, the ASR varies markedly, reflecting different economic specializations – ranching, mining, subsistence, commercial enterprise, plantation labor, etc. Migration has been affecting the family dynamics of the Makushi for decades and this has led to considerable between community variation in the ASR as males migrate into Brazil and Venezuela in search of wage labor and females are pulled into urban areas in search of domestic work. These fluctuations in male and female populations affect the availability of potential mates for marriage and as such reproductive strategies of men and women are expected to vary. While our analysis remains incomplete, our initial findings are quite intriguing. We began by looking at sociosexuality scores (willingness to engage in uncommitted sex as measured by the Sociosexual Orientation Inventory; SOI) of men and women across the communities of varying ASR. When there are few men in a community (men are in demand), we find that men have high scores; higher both than women in the same community as well as men in communities with few women. Conventional theory assumes distinct differences in the sociosexuality scores of men and women across communities– with men having higher scores because they are able to benefit more from mating multiply than women. However our findings counter this assumption, and we find that when the ASR is high (women are in demand and men are abundant), sociosexuality scores of men and women are indistinguishable. Ultimately, we see dramatic changes in male sociosexuality across the ASR. Men are responding to numbers of women by adjusting their promiscuity to match mating market demands, and becoming less willing to engage in uncommitted sex, to the same level that women are, when more abundant. A number of conclusions can be drawn from our initial analysis. First is that there is considerable variation in behavior, both within and between the sexes. Thus, any research that seeks to study human mate choice must take features of social context into consideration when attempting to explain behavioral variability. Second is that it is definitely wrong to assume homogeneity of behavior within men. Clearly how men interact with women depends on many different features of the environment, including the adult sex ratio. Third, women show less variability in sociosexuality with ASR than do men. This, of course, does not exclude other adaptive responses of women in, for example, the realm of mate choosiness on various traits by ASR. However, does this indicate that cultural mores affect women's sexual behavior more than that of men? We simply do not know, but this is a question we will be pursuing. In conclusion, here we have utilized new developments in behavioral ecology that identify ASR as a key factor influencing how men and women respond to opportunities for uncommitted sex. We propose that continued attention to developments in modern evolutionary theory will help rescue evolutionary social science from the stereotypical claims with which it has been associated, and help provide insights into the environmental and/or culturally transmitted cues with which this variation is associated.
