Why Beautiful People Have More Daughters: From Dating, Shopping, and Praying to Going to War and Becoming a Billionaire–Two Evolutionary Psychologists Explain Why We Do What We Do (14 page)

Men who are cuckolded do not manage to transmit their genes to the next generation and achieve no reproductive success. Men are therefore selected to be very sensitive to cues to possible cuckoldry and to attempt to guard against the possibility. A man would therefore only invest in his mate's children if he was reasonably certain that they were genetically his. In the absence of DNA tests (which did not exist in the ancestral environment), how could men ever be certain that their children were genetically theirs?

The child's physical resemblance would be one clue available to men in the ancestral environment. If the baby looks like the father, it is more likely that it is genetically his, whereas if the baby looks nothing like him, or, worse yet, looks a lot like his neighbor, then it is doubtful that he is its genetic father. This reasoning leads evolutionary psychologists to predict that, holding constant the probability of cuckoldry, babies who resemble their father are more likely to survive than babies who do not resemble him (or resemble the mother), because the father of babies who resemble him is more likely to be convinced of his paternity and to invest in them, thereby increasing their chances of survival, whereas the father of babies who do not resemble him (or resemble the mother) is less likely to be convinced of his paternity and to invest in them, thereby decreasing their chances of survival. Over many generations throughout evolutionary history, genes that make babies resemble the father therefore survive, whereas genes that make them resemble the mother do not, and so more and more babies come to resemble the father, until most babies are born resembling the father, not the mother.

This is precisely what two psychologists at the University of California, San Diego, Nicholas J. S. Christenfeld and Emily A. Hill, discover in their ingenious study.
²³
Christenfeld and Hill show the subjects in their experiment a picture of a child at ages 1, 10, and 20, and a set of three pictures of adults, one of whom is the real parent (mother or father) of the child. They then ask the subjects to match the child with the correct parent. Christenfeld and Hill's subjects therefore have 0.33 probability of selecting the right parent by chance. If the child truly resembles the parent, then the subjects should be able to match the two pictures at a much higher probability.

A major finding in Christenfeld and Hill's experiment is that children in general do not physically resemble their parents. The subjects are not able to match the picture of the child at any age to the picture of either the mother or the father better than expected by chance. The only exception, however, is the matching of 1-year-old babies to their father. The subjects are able to match both baby boys (0.505) and baby girls (0.480) to their father (though not to their mother) at statistically significantly greater rates than by chance. That means that one-year-old babies resemble their fathers, as might be expected from the evolutionary psychological logic presented above.

Christenfeld and Hill's finding was widely reported in the media, but it has also become one of the most controversial contentions in evolutionary psychology, not least because, although their explanation had impeccable logic, their finding could not be replicated. To date, attempts at replication have shown that newborn babies objectively resemble mothers more than fathers,
²⁴
and infants and children resemble both parents equally.
²⁵
Thus, the question of whether newborn babies objectively resemble the father more than the mother must be treated as an open one until more experiments are conducted.

But Who Are Newborn Babies Said to Resemble?

There is a related finding that is much less controversial and well replicated, however. Nature may or may not help assure fathers of their paternity by making babies resemble them; however, friends and family—in particular, mothers and their kin—certainly do. In three separate studies conducted in three different North American countries (Canada, Mexico, and the United States) in three different decades, mothers and maternal relatives are far more likely to allege the baby's paternal resemblance than its maternal resemblance.
²⁶
This happens even when the newborn babies in fact do
not
resemble their fathers.
²⁷
Such allegations of paternal resemblance assure the fathers of their paternity, whether the babies actually resemble them or not.

Further, in most societies, babies get their last name from the father, not the mother, thereby once again suggesting to the father that he is the father of the baby. (Russians go one step further and give their babies their
middle and last names
after the father.) This is true even in societies where women routinely keep their last name when they get married and do not adopt their husband's name. The children of such parents nonetheless usually get their last name from the father, not the mother. Many Western professional women these days often keep their last name when they get married. Most of their children still get their last names from the father, not the mother. By giving their children the father's last name, these women are essentially (albeit unconsciously) saying, “Honey, it's yours” (even, or
especially
, when it is not). They need to reassure their husbands of their paternity, but do not themselves need to be reassured of their maternity; they know for sure. Mommy's baby, Daddy's maybe. And for 10–30 percent of daddies, it is not.

Q. Why Are There So Many Deadbeat Dads but So Few Deadbeat Moms?

When married couples with children get divorced, chances are that the children stay with the mother, not the father, especially when they are young. According to the 1992 March/April Current Population Survey in the United States, conducted by the US Census Bureau on a nationally representative sample, 86 percent of custodial parents are mothers.
²⁸
Further, many of the noncustodial fathers who have agreed, either voluntarily or via court order, to pay child support default on their commitment and often become “deadbeat dads.” The first national survey of the receipt of child support, conducted in 1978, reveals that less than half (49 percent) of women awarded child support actually receive the full amount due to them, and more than a quarter (28 percent) of them receive nothing.
²⁹
The percentages have remained more or less constant since. In 1991, 52 percent of custodial parents awarded child support received the full amount; 25 percent of them received nothing.
³⁰
Why are women so much more dedicated parents than men? Why are there so many deadbeat dads but so few deadbeat moms?

On the surface, this massive sex difference in the dedication to parenthood might appear puzzling, since both the mother and the father are equally related to their children genetically; each transmits half of their genes to their child. However, there are two biological factors that combine to make fathers far less committed as parents than mothers.

“Mommy's Baby, Daddy's Maybe”

The first is paternity uncertainty. As we discussed in chapter 2 and above in this chapter (“Why Does the Baby Have Daddy's Eyes but Not Mommy's?”), because gestation for all mammals (including humans) takes place internally within the female's body, the male can never be certain of his paternity, whereas maternity is always certain. And paternity uncertainty is not a remote theoretical possibility. As we mention elsewhere (see “The Evolutionary Psychological Perspective” in chapter 1 and “Why Are There Virtually No Polyandrous Societies?” in chapter 4), the estimated incidences of cuckoldry (men unwittingly investing in another man's genetic offspring) in contemporary industrialized societies is substantial (between 10 and 30 percent), although a comprehensive recent review suggests that the actual incidence among Western populations may be much lower, at around 4 percent.
³¹
Thus, this is a very realistic possibility for any father in contemporary Western society (and probably elsewhere throughout history as well). Naturally, men are not motivated to invest in children who have a distinct possibility of not being genetically theirs.

The Best They Can Do Is Better for Men

The second biological factor that makes fathers less committed parents is their higher fitness ceiling (the best they can do reproductively). Fetuses gestate for nine months within the female body, and infants are, at least in the past, nursed by the mother for several years after birth, during which the mother is usually infertile. Women also have a much shorter reproductive life than men do. These two factors combine to create a much higher fitness ceiling for men than for women. Men can potentially have many more children than women can. (Remember Moulay Ismail the Bloodthirsty?) The sex difference in the largest possible number of children means that, while
reproductive success
is equally important to men and women (in fact, to all biological organisms),
each child
is far more important to the mother than it is to the father. Each child represents a far greater portion of a woman's lifetime reproductive potential than it does a man's. If a 40-year-old mother of five deserts her children and they die as a result, she will likely end her life as a total reproductive loser, having failed to leave any copy of her genes in the next generation. If a 40-year-old father of five does the same, he can go on to produce five (or ten or twenty) more children.

Both paternity uncertainty and the higher fitness ceiling make fathers less committed parents than mothers, and this is why there are so many more deadbeat dads than deadbeat moms; very few women abandon or neglect their children. Ironically, it is the mother's greater commitment to her children that allows the father to neglect them even more.
³²
Knowing the mother's greater commitment to her children, the father can abandon them, secure in the knowledge that the mother would never do likewise, because if she did, the children would be virtually certain to die. In other words, divorced parents with children are playing a game of chicken, and it is usually the mother who swerves. Most fathers would probably prefer to invest in their children and raise them by themselves rather than see them die, but they normally do not have to make this difficult decision, because they know that the mother would never abandon them. The mother's greater commitment to her children ironically allows the father to have his cake and eat it too, by moving on to the next marriage and family in which to invest.

Are Mothers Always Good Parents?

None of this means that all mothers are always good parents or better parents than fathers. Sometimes mothers even kill their babies. However, evolutionary psychological logic can even explain who is more likely to kill their babies, and why.

Statistics show that very young mothers, by far, are the most likely to kill their babies, and older mothers are the second most likely to do so, but for different reasons.
³³
Very young, teenage mothers kill their babies because they still have most of their reproductive lives ahead of them, and they can make more babies in the future even if they kill the one they just had. Having a baby under unfortunate circumstances (such as without the father willing to invest in it) not only threatens the well-being of the baby but also jeopardizes the mother's chance of finding a mate in the future. And teenage mothers are more likely to have their baby under unfortunate circumstances than others.

Older mothers (above the age of 35) kill their babies for a different reason. They are more likely to have defective babies because of their age. Every child (defective or otherwise) consumes parents' resources. Since defective children are much less likely to attain reproductive success, from the purely genetic point of view, any resources invested in children who will not have children themselves are wasted. Such children are taking away valuable resources from other children who have better reproductive prospects. Older mothers are more likely than younger mothers to have other children they must also raise. So parents are designed not to invest in defective children. (By the same token, parents invest more in better-looking children than in less good-looking children, and in more intelligent children than in less intelligent children.)

Yes, the evolutionary logic is very brutal, cold, and heartless. It only cares about the survival of the genes.