A LINE ON LIFE

9/8/96

Choosing a Spouse A Product of Evolution? *

David A. Gershaw, Ph.D.

Across history and many cultures, there have been polygamous men and monogamous women. Men are allowed to mate with many women. Women are severely punished for even glancing at another man. Many people believe that these are merely sexist customs to control women. However, evolutionary psychologists present another view.

Evolutionary psychologists follow Charles Darwin with his theory of natural selection. Darwin theorized that traits develop in animals because they ensure survival. In the 1960s, biologist Robert Trivers advocated sexual strategies that would ensure the survival of prehistoric men and women.

Trivers justifies his conclusions about gender differences by their ability to parent offspring. Women are limited in the number of children they can bear. Since women provide primary child care for years after birth, they require many resources. However, men can sire as many children as they can find women to impregnate. They don't even have to stay for the birth.

In his book, The Evolution of Desire (Basic Books, 1994), psychologist David Buss expands this theory. In contrast to being sexist, evolutionary psychologists hope they can help both sexes understand their behavior and that of their mates. This information might even help them get along better. Buss submits several basic ideas related to the theory.

In 1990, over 10,000 people in 37 different cultures were surveyed. These were various cultures from the United States and European countries to Zambia and Indonesia. Both men and women were asked what qualities they preferred in an "ideal" mate. In most cultures, both sexes rated kindness and intelligence as the most desirable traits. Beyond that, sexual preferences were extremely different. Women rank "good earning capacity" and ambition higher than physical attractiveness. On the other hand, men preferred physical beauty and youth more. The difference in ratings between the sexes varied across cultures, but the pattern was constant.

These preferences are supported from other cross-cultural surveys. In contrast to women, many more men seek short-term relationships casual sex, one-night stands, short affairs with many sexual partners over their lifetime. Most men are willing to have sex with a partner they have known only briefly. This is not true for most women.

From an evolutionary view, casual sex offers fewer risks and more benefits for men. They can scatter their genes among a large number of offspring while using few resources.

On the other hand, this behavior does not favor women. Women risk being labeled as "promiscuous." (Men like promiscuous women as short-term mates, but not as long-term mates.) In addition, women risk raising children without help. When they have children, they reduce their chances of attracting another mate. Why should a man waste his resources raising another man's child?

This leads to different ploys to get a mate. Each gender uses deception to attract a partner. As a group, men pretend that they are more committed than they really are. They tend to exaggerate their material assets and professional expectations. Women emphasize their physical beauty. To compete for mates, women need to rely more on hair care, jewelry and makeup. Beauty fades with age, but older men are more likely to have amassed resources. Thus older men are viewed as good potential partners, while prospects fade for older women.

Even when "having affairs," there are gender differences. Usually a woman is unhappy with her primary relationship and is looking for someone better. In contrast, men are seeking sexual diversity. Unfaithful men are not less happy with their marriages than those who remain faithful.

Of course, men become extremely jealous, if they think their partner may be having sex with another man. This can be explained by the evolutionary viewpoint. Humans are the only species whose females have concealed ovulation. Men cannot tell when the women are fertile. If sexual relations occur with other men, the original partner cannot be sure if she is bearing his child. He may be "wasting" his resources on an other man's child.

Women are more jealous if their men become emotionally involved with other women. In contrast to just sex, emotional involvement with another woman might mean fewer resources for her and her offspring. In a study that measured psychological arousal to imagined situations, men and women demonstrated arousal increases that supported these differences.


With insight and effort,
we can develop the relationships we desire
in spite of our genes.


Buss sees humans as a "collection of evolutionary determined mechanisms" that push us in certain directions. However, Buss does not believe that these gender relationships are inevitable. In fact, by understanding the fantasies of the other sex, it may be easier to reduce the conflict between the sexes. We can go along with our innate tendencies, or we can modify them to fit our social and cultural needs. It is like maintaining a healthy diet rather than following our genes by eating fatty foods. It takes more effort to change our behavior, but the choice is ours.


* Adapted from Beth Azar's "Modern mating: attraction or survival?", and "The art of love and deception," APA Monitor, August, 1996, pages 30-31.

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