Playboy reports that actress Scarlett Johansson said “I don’t think it’s natural to be monogamous.” I’m sure Hugh Hefner and lot of other men whole heartedly agree with her. But on examination her statement is ignorant of the history of human evolution and the peculiar pressures that formed the human psyche.
I believe Richard Dawkins (1941—) has it pretty much right in his book, The Selfish Gene. Stephen Jay Gould (1941-2002) hated that book and probably hated Dawkins as well. Dawkins believes that selfish genes trying to lever their way into the next generation are what determines the phenotypic expression of the organisms that host them. Gould believed it is the organism that determines the make up of it genes.
If Dawkins is correct and genes are the unit of natural selection, then Scarlett Johansson is wrong. Monogamy is a part of human nature, for several reasons.
Humans are peculiar to the animal world because of our long childhood and long life span. The utter helplessness of the human female during pregnancy, her need of assistance while carrying an unborn child and the child’s need of care from its parents for an unusally long period tells us why monogamy is our natural state. If it’s all about genes trying to lever they way into the next generation then it is imperative that the animals genes inhabit be well adapted to survival. An animal that dies before reaching sexual maturity thwarts it genes from reaching the next generation.
The result of selfish gene competition for survival has created a human being in which both male and female humans benefit from sharing a strong bond of affection. They also share a strong desire to have the other remain faithful to them. When humans lived in caves a pregnant woman abandoned by her husband would probaby not survive. Her husband would be possesive of his wife because he would not pass his genes to the next generation if his wife died or was impregnated by some other male. This gave each an incentive to care for each other and not to cheat, or at least not to get caught.
You might think it was only the woman with an incentive not to cheat. After all, females are limited to only about 20 possible offspring in their entire lives, whereas a man could impregnate hundreds of even thousands of females and spread his genes widely. The brake on this is the possessive attitude toward his female partner his genes have given him. The last thing selfish genes want is to inhabit the body of a man who devotes his resources to nurturing the offspring of some other man. Thus, the phenotypic expression in the human male is a man that will likely take extraordinary steps to prevent his partner from cheating and to have a murderous attitude toward anyone who breaks that barrier.
The incentive for the female not to cheat is first, not to lose the care and support of her partner, ans second, not to be murdered by him. This second impulse was very strong during most of human evolution which took place before civilization began and legal consequences against murder were established. Even so, as late as the mid-20th Century juries were reluctant to convict paramour killers.
In other species males can be seen to battle brutally over mating rights. They seldom kill each other in those fights. Humans kill each other more often and the main causes are love, money and revenge, in that order.