An essay I wrote recently on evolutionary psychology. Sorry for the stilted language; it was inspired by the books I’ve been reading, especially David Buss’ “The Evolution of Desire”. Enjoy.

Most observers will agree that for men, the primary sexual strategy is to inseminate as many females as possible, to ensure that at least some of their genetic material will survive into the next generation. However, there is a secondary sexual strategy that men can, and often do, choose: to provide their resources of time, attention and material goods to a single female, in order to reap the benefits that this strategy promises.

Those benefits include (but are not limited to) status in the community, as well as more secure knowledge of the disposition of their progeny.

Men are at a disadvantage, in that it is difficult to be certain that the progeny of their mates are, in fact, their progeny. Those men in the past who provided their resources to a female in order to raise children who did not share the males genes would be at a disadvantage, evolutionarily speaking.

Determining paternity is a challenge for mammals, primates, and especially humans, because conception takes place internally in the female. Maternity is never in question for the female. Therefore, humans have developed adaptive mechanisms for dealing with this.

One such mechanism is psychological in nature. It is called “jealousy”.

From the standpoint of evolution, a man and a woman who are mates are providing each other with some benefit. The man who has opted for the secondary sexual strategy of long-term commitment is offering his resources to the female, and is expecting the female to provide him with a return benefit. In most cases, the benefit he is expecting, and therefore the attribute a man most values in a long-term relationship, is fidelity. Men who are seeking long-term mates do not value promiscuity in females, and do not see infidelity as a positive. They stress fidelity and expect their mates to provide them and them alone with sexual access.

Thus, it is expected that males who are seeking long-term mates to view a woman’s activities with a jealous eye. Since paternity is always in question, a deeply-rooted fear of being cuckolded, well below the conscious level, likely exists in many, if not most, men.

To be sure, jealousy is active in females as well. A male who is active with other females is a threat to the woman, as the male may decide that other children are more valuable and may split his resources, or begin providing them to the other mother and children exclusively. However, the adaptive challenge that is present for the male (to ensure that his resources are only going towards his own children) is not present at all for the female, and in fact a woman may exploit the paternity challenge by getting resources from one male while bearing the children of another. In this way she can have the best of both worlds.

This female strategy, however, butts right up against the challenge posed to men, and few men would endure this situation for very long. The typical male reaction to infidelity is anger or other violent action, while the typical female reaction to the same circumstances is sadness. For the male, a promiscuous mate means that he cannot be certain any of his genetic material will survive into the next generation, thus, his genetic line is threatened to its root. For the woman, infidelity simply means that the males resources may be withdrawn, and, depending on the other resources available to her, this may range from merely inconvenient to a life-threatening action.

Although the past illuminates the root causes of jealousy, and the differential response the two genders have to the acts that trigger this emotion, it does not condemn all humans to suffer the extremes suggested by this essay. Remember, though, that adaptations to evolutionary challenges, such as this one, provide a framework for understanding individual motivations.

In the prehistoric past, it may have been common for men to sequester their mates from all other male contact, and to become enraged at a male’s attention towards their mate; enraged to the point of murder. In modern humans, this is, sadly, still all too common. But much more likely, and much more palatable among humans that ascribe to a moral code, a man may simply decide that a woman who wishes to entertain other male company is not offering acceptable behavior for a long-term commitment and will choose to terminate the relationship and look elsewhere.

Among civilized humanity (I apologize for the loaded term “civilized” but can find no other way to separate modernity from our ancestry) relationships need to fulfill both parties needs, and, due to our evolutionary history, males primary needs in a long-term relationship is fidelity in their mates.