In a study involving over 10,000 people from 37 cultures, Buss (Psychology/Univ. of Michigan) uses evolutionary theory to explain the psychological mechanisms behind how and why people choose, keep and discard their mates.
Mating, according to Buss, is not a sentimental or humane activity; it is, rather, as competitive, conflictual, and manipulative on the human level as it is among the insects. To provide for themselves and their offspring, women seek providers--men with money, power, maturity, ambition, stability, commitment, health, and cooperative natures. Men, for similar reasons, invest their time, resources, and sperm in young, beautiful, and fertile women who will give them heirs and status. At the same time they retain a primitive ability for casual sex as well--a sexual mechanism that is less selective and can be satisfied in more primitive ways such as fantasy, homosexuality, and incest. The capacity for multiple partners, casual sex, jealousy (a series of protective responses), and divorce are all adaptive mechanisms to help people--though mostly men--achieve their reproductive potential. Detailed analysis of various forms of mating rituals considered in large anthropological and biological contexts explain adaptive techniques for attracting and keeping mates and what happens when they get out of hand, ancestral instincts becoming destructive (abuse and rape). Scientifically rigorous, the study, on a human level, is abstract and statistical (75 societies reported infertility as a cause of conjugal dissolution); the detail is found on the animal level, as in a lurid scene of mating between scorpion flies.
However incomplete sociobiology and evolutionary psychology may be in explaining human relationships, they clearly affirm the value of raising the instinctual to the level of consciousness and the miracle, as Buss eloquently concludes, of modern marriage as a "crowning achievement of humankind.''