Kipsigis people of Kenya and a Life History

• Life History Theory: Explains anatomy and behavior through natural selection.

• Sexual Selection Theory: Uses the "cost of reproduction" metaphor.

• Commoditization: Women valued based on reproductive potential.

• Bridewealth: Examples include dowry, brideservice, and sister exchange.

• Kipsigis Study: Physical condition, age, and economic value influence reproductive value.

• Universal Practices: Similar mate choice behaviors found globally.

• Nature vs. Nurture: Ongoing debate with no consensus.

• Human Cooperation and Culture: Key factors in human ecological success.

Wikipedia defines life history theory as “[seeking] to explain aspects of organisms' anatomy and behavior by reference to the way that their life histories...have been shaped by natural selection”.  As Dr. Meehan explains in her lecture Bridewealth, sexual selection theory uses the metaphor of the “cost of reproduction” for understanding the sexual motivations of individuals.  This metaphor considers sexually mature women “as a kind of scarce commodity”.  In life history theory, the concept of reproductive value (RV) is used to describe this commoditization, whereby age and physical condition determine the number of offspring a woman can produce over the course of her lifetime. In fact, as evidenced in differing cultures all over the world, women are literally commoditized in a system known as bridewealth.  Dowry, brideservice, and sister exchange are examples of bridewealth commonly found across cultures. 

As demonstrated in the study of the Kipsigis people of Kenya presented by Dr. Meehan, where the bridewealth system is employed in arranged marriages, data show that, in addition to physical condition and age, a bride’s likelihood of fidelity and economic value correlate with her reproductive value in the community.  Other aspects of sexual selection such as heritable traits, male-male competition, and female choice may also play a part in evaluating a potential mate’s reproductive value among humans.  This academic approach to understanding sexual selection in a cultural context is known as evolutionary behavioral ecology and helps contextualize seemingly bizarre mating habits observed in cultures other than our own.

But in North America, aspects of bridewealth can be found in the form of engagement rings, arranged marriages among some social groups, or even parents’ steering of offspring to successful and hardworking mates.  In this way, unfamiliar patterns of mate choice in other cultures are like sexual selection behaviors in the U.S. and everywhere else in the world.  Additionally, while natural and sexual selection do play a role in human mating behavior, there is not a broad consensus among biologists and social scientists regarding this nature versus nurture question, as complex human culture is extremely rare in other mammals.  Human cooperation, and the advent of a rapidly changing, advanced culture, have had a unique impact on human life ways.  So ‘those aspects of organisms’ behavior and anatomy” evaluated by life history theory involving sexual selection by humans may be best understood in the context of both natural and cultural phenomena.  As biologists Joan B. Silk and Robert Boyd note, “the three Cs – cognition, culture, and cooperation – have made humans a runaway ecological success” (418).

References

Boyd, Robert. How Humans Evolved (Seventh Edition), 7th Edition. W. W. Norton & Company, 20140910. [Yuzu].

Meehan, Courtney.  Lecture 7, “Bridwealth.”  WSU Global Campus.  Spring, 2017.

Wikipedia contributors. "Life history theory." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 1 Feb. 2017. Web. 9 Mar. 2017.