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My son starts his last soccer season this weekend. I expect him to close out strong. He's captain, this year, of his college team: physically and mentally at the top of his game. Mothers tend to be proud of their sons.
As it turns out, Oedipus is a lot less complex than Freud thought. Back at the beginning of the last century, in his book The Interpretation of Dreams, he remembered Sophocles' tragedy — the one where Oedipus kills his father Laius on the road, becomes king of Thebes, then marries his mother, Jocasta. "It may be that we were all destined to direct our first sexual impulses toward our mothers, and our first impulses of hatred and violence toward our fathers; our dreams convince us that we were," Freud wrote, speaking for himself.
But fathers have often fought with their sons, and the objects of competition have often been women. In a Freudian world, they compete over the mother. In a Darwinian world, they fight over status, inheritances — and other girls.
That logic begins, again, with Robert Trivers. In a 1974 paper on parent-offspring conflict, he noted that in sexually reproducing species, parents and their offspring are related by half, but that parents and offspring are fully related to themselves. The result is that offspring should be naturally selected to want twice as much as their parents are naturally selected to give. In Trivers' words: "As long as one imagines that the benefit/cost ratio of a parental act changes continuously from some large number to some very small number near zero, then there must occur a period of time during which ½ < B/C < 1. This period is one of expected conflict."
When sons do come into competition with their fathers, a mother will tend to side with her son. That too follows from Trivers' logic. As he pointed out in a 1972 paper on parental investment, a woman under optimal conditions will raise on the order of 10 children, but a man under optimal conditions will raise an order of magnitude more. It follows that a woman gains little by mating with more than one man, but she gains a great deal by helping her son.
Trivers wasn't explicit about the conflict between sons and fathers, but John Hartung was. Fathers and sons should be selected to compete with each other — not over the son's mother, but over other mates. "Put plainly, every successful male has a mother, and every mother with highly successful sons has an extraordinary number of grandchildren," is how Hartung summed up. Against Laius, Oedipus and Jocasta should be on the same side. And incest should be the last thing on their minds.
The cross-cultural evidence bears that out. At the end of the last century, Nancy Thornhill made the case that rules against incest between sons and their mothers are conspicuously absent across cultures. But that rules against "incest" with other women — against sex with step-mothers, daughters-in-law, and so on — are common. Men don't have to be reminded to stay away from their mothers. But they do have to be reminded to stay away from their fathers' other wives.
And as Martin Daly and Margo Wilson years ago pointed out, any sex-bias in parent-offspring conflict is much more likely after daughters and sons have grown up. As long as children are in Freud's circumpubertal (age 11-16), latency (age 6-10), or Oedipal (age 2-6) stages, sex-bias is nonexistent — at least in the homicide evidence. Parents are equally likely to kill their underage sons or daughters. But fathers are much more likely to kill, or be killed by, their adult sons. In Daly and Wilson's words: "The data match Trivers' model better than Freud's."
The historical evidence matches Trivers' model as well. Centuries before Sophocles, Hesiod, who was Homer's contemporary, wrote the oldest of Greek myths. In his Theogony, the sky god, Ournaos, has sex with the earth goddess, Gaia, who gives birth to a houseful of children. But as soon as Gaia's sons are born, Ouranos hides them away from the light of day. Their mother comes to the rescue. She makes a "saw toothed scimitar," a "great long jagged sickle," and tells her boys that it's time to get back at their father. And her youngest son, Kronos, who goes on to become the father of Zeus, "harvests his father's genitals," and makes himself a king.
Centuries before Hesiod, there was another myth like that from the Ancient Near East. King David lived in an ivory palace, wrapped in aloe and cassia scented robes, entertained by stringed instruments, and surrounded by "ladies of honor" and "virgin companions." The Bible names 20 of David's children: 19 boys, and Tamar — David's virgin daughter, who's raped by his oldest son. Which made another of Tamar's brothers mad. Absalom bided his time, but in the end, "went in to his father's concubines, in the sight of all Israel," and started an insurrection. 20,000 men died in the battle he fought against his father in the forest of Ephraim; and Absalom was one of them. He got hung up in an oak, with 3 darts in his chest. And the concubines in question were put under house arrest, "shut up until the day of their death" (Psalms 45:9, 14; 2 Samuel 6:20, 16-20).
Ever since the Norman Conquest, for the better part of a millennium now, strong queens of England have successfully promoted their sons. Kings whose mothers were heiresses in their own right started reigning 5 years younger, on average, than kings of mothers who were not; and their reigns averaged over a year longer. Kings of mothers whose fathers were kings began their reigns almost 6 years before nonroyal mothers; and they reigned for an average of 8 more years.
Some queens of England rebelled against their husbands. Eleanor, the heiress of Aquitaine, backed her sons' failed revolt against their father, Henry II "the Lion" — for which she was locked up in various castles around England for the next 16 years.
Other queens, like Mary Queen of Scots, had their husbands blown up. Mary married her lover 3 months after that, then she abdicated in favor of James VI, her one-year-old son — who became England's James I.
Oddly enough, the same thing might happen in apes!
References
Betzig, Laura. 2012. Fathers vs sons: Why Jocasta matters. In M. Fisher et al. eds., Evolution’s Empress. New York: Oxford University Press.
Betzig, Laura. 2014. The French connection: Parent-offspring conflict and the English revolution. In T. Shackelford and R. Hansen eds., The Evolution of Sexuality. Berlin: Springer.
