The Folly of Fools (14 page)

Second, with the added factor of a long period of parental investment soaked with language, there are many opportunities for conscious and unconscious manipulation, including induced self-deception, in which the parent can induce a pattern of self-deception in the offspring that serves the parent’s interests but not those of the offspring expressing the self-deception. The child may grow to believe that its parents are acting in its true interests when in fact they are not. The offspring may not be in a position to free itself of such an imposed self-deception until it no longer requires parental investment, giving an added reason for emotional turbulence in late adolescence, along with open hostility toward parents. Adults, in turn, may differ in the degree to which they suffer costly effects from earlier parental manipulation. In addition, parents are not a unit; they are a father and a mother, with different interests in offspring manipulation because the manipulation affects them and their differing sets of relatives.

Third and unexpectedly, relatedness considerations automatically split the organism into multiple selves, with differing interests, the most important for our selves being our maternal self and our paternal one. Formerly, we used to believe that an organism had a single self-interest. It had a unitary aim—to maximize its genetic reproduction. Kinship theory says this can’t be true. Different genes within us have differing rules of inheritance, and this will give them contradictory interests. For example, the Y chromosome is always passed father to son. It is not selected to have any interest in daughters. Does that mean we expect fathers to be at least slightly biased toward their sons? Not at all. The male’s X chromosome is passed only to his daughters and it is more than ten times as gene-rich as his Y, so if anything, men should show a slight genetic bias toward their daughters. No one knows whether this is true, but there is some evidence that paternal grandmothers favor their granddaughters over their grandsons according to the differing chances that their X chromosome will be found in them (½ versus 0).

The Y and the X are only small parts of the whole genome. The main genetic split within us is between our maternal and paternal halves, which are equally strong. There are a few hundred genes in us that are active only if inherited from our mother, so-called maternally active genes, and about an equal number from the father, so-called paternally active ones. Maternally active genes are selected to promote maternal interests and paternally active, paternal. This generates internal genetic conflict in which two separate genetic selves compete for control of our behavior and larger phenotype. This conflict has two important effects. We expect deception between these two halves—not directed toward outsiders but toward each other. For example, maternal genes in you may overemphasize the benefits to the organism as a whole of acting on its special relatedness to others (when these are maternally biased), while paternal genes may be selected to discount such maternal effects. Second, we also expect differences between our two halves over whom to deceive in the outside world (with or without self-deception). As we shall see below, this split in us runs deep, both from early-acting genes affecting growth and consumption of parental resources to later-acting ones affecting adult behavior.

PARENT/OFFSPRING CONFLICT

Because parents typically are related to each offspring by ½ but not by 1—and vice versa—there is ample scope for conflict between the two parties. This conflict usually concerns how much parental investment the offspring receives and what its behavioral tendencies are, as these affect its relatives. The parent is selected to maximize the number of surviving offspring it produces, but the child is twice as related to itself as to its full siblings, so it is selected to try to gain more than its fair share of resources—though not so much more that it inflicts twice the cost on its siblings as the gain it enjoys itself. Deception is an important part of the child’s repertoire, pretending greater need than is actually being experienced and manipulating the parent psychologically, sometimes against the parent’s better instincts. The parent may be selected to minimize the appearance of available resources, the better to save some for other offspring. One critical choice the parent has is whether to impose its will, insofar as it can, or opt for a fair split with the offspring. The latter, in principle, should reduce future conflict with the offspring, especially if in response it adopts a similar posture. One danger of complete domination is the turmoil that may erupt when the offspring is as physically large as the parent and is cognizant of the parental style to which it has long been exposed.

Regarding the offspring’s general behavior, it is selected to act altruistically toward a relative only when the benefit times degree of relatedness is greater than the cost to itself (B>2C for full siblings), but the parent would prefer to see altruism whenever there is a net benefit to the parent’s offspring—in this example, B>C. Thus, parents are selected to mold their offspring into being better people (more altruistic, less selfish) than they are inclined to act on their own. This may take the form of punishing behavior as being generally immoral (instead of merely counter to the parent’s self-interest).

CASES OF EXTREME ABUSE

The long period of parental investment in humans means that there are many opportunities for each party to respond to the other’s actions. One important consequence is that a child who is receiving insufficient investment or actual abuse maybe put in an awkward position where resistance is concerned. In the extreme case, resistance is likely to only make matters worse; it will provoke additional abuse and withdrawal of investment. Thus, until children reach the teen years, they may, in general, have to submit—and the more so the harsher the regime under which they live. There also are more things they need to hide from the outside world, so lack of resistance includes lack of disclosure to others, and here the evidence is clear. For abuse in general (physical, emotional, and sexual), the more the abuse is perpetrated by a close relative (or stepparent), compared to that from a more distant figure, the longer the children take to disclose the abuse, if at all. We are talking about delays of a year or more. Intervention is less likely and caregivers less supportive. And there are negative immune effects that endure into adulthood (see Chapter 6).

Here the child may be favored by natural selection to keep up a good front, which may involve self-deception, such as disassociation and selective recall. In disassociation, the mind is split into two (or more) relatively separate parts, one of which fails to recall the abuse or see it as such—perhaps the self that is usually shown to the parent. Disassociation is more common than selective recall in those who have been abused, and this disassociation compromises intellectual performance, for example, on the Stroop test (recognizing words denoting color that are written in different colors).

The notion that children completely repress memory of extreme trauma, only to recall it years later in full detail, has been shown to be unlikely in most cases, but this does not mean that amnesic factors are not at work in trauma, of which disassociation is only one example. Again, it is the closeness of the abuser that is associated with the greatest memory defects. For all forms of impairment, abuse by a caregiver induces more memory impairment than similar abuse by non-caregivers. Is this because it is inherently more offensive and in need of memory eradication or because pressure from caregivers to keep one’s silence is especially strong? It may be both. We know that the tendency to share with others is less frequent when the abuse comes from a caregiver.

GENOMIC IMPRINTING

As mentioned already, one of the most striking discoveries in the past thirty years of genetics is that we are expected not to be unitary creatures with a single self-interest, but to have a paternal genetic interest and a maternal one, which may differ, with each acting to promote a view of the world from its standpoint. Biologists used to think that genes had no memory of where they came from, thus they computed the average degrees of relatedness cited earlier—half chance through Mom, half chance through Dad. In the 1980s, biologists began to discover a minority of genes whose expression level depended on which parent contributed it. Often one copy was active and one inactive. So there are paternally active genes and maternally active ones. With activity limited by parental origin, these genes can act not on average relatedness, but on exact relatedness to each parent (0 or 1) and their relatives.

The first two imprinted genes described in mice tell the whole story.
Igf2
(insulin-like growth factor 2) is a paternally active gene that activates growth in fetal life by increasing rates of cell division. A single active copy increases size at birth by 40 percent compared to no active copies. Why does this make sense? In competition over access to maternal investment, paternal genes in offspring are inevitably less related to siblings than are maternal genes. Multiple mating by a female for each litter or changing fathers between litters lowers paternal relatedness among the resulting siblings while leaving maternal relatedness unchanged. Thus, paternal genes will weigh effects on self relatively more heavily than effects on siblings (compared to unimprinted genes or maternally active ones), preferring faster fetal growth rates and relatively larger size at birth.

The proof is in the pudding. An oppositely imprinted gene has exactly opposite effects.
Igf2r
(insulin-like growth factor 2 receptor) is maternally active and, in mammals, its protein has evolved a secondary binding site to Igf2, which is carried to lysosomes and degraded. Indeed, Igf2r gets rid of 70 percent of all of the Igf2 that is produced. As a result, it lowers the fetal growth rate by about 30 percent. This is no way to build a railroad. Here are two large, costly opposing effects that virtually wipe each other out. This is not good for the individual but is exactly what you would expect if there were two opposing forces within the offspring. Evidence confirms that imprinted genes that affect early development almost always obey “Haig’s rule”—paternally active genes have positive effects on growth during maternal investment, while maternally active ones have negative effects.

One final line of evidence is worth mentioning. Although mice that are artificially manipulated to have a doubly paternal or doubly maternal genome fail to develop, individuals will develop successfully if only a fraction of their cells are doubly paternal (their nuclei from two sperm cells) or doubly maternal (nuclei from two eggs) and the rest are normal cells. Such chimeras reveal a striking fact. The more doubly maternal cells, the smaller the newborn; the more doubly paternal cells, the larger the newborn, exactly as expected. But there is a surprise: the relative size of organs inside the mouse is also changed. For example, the greater the number of doubly paternal cells, the smaller the neocortex and, hence, the brain. The hypothalamus is affected in the opposite way: doubly paternal cells do well in the hypothalamus, while doubly maternal ones disappear. Let us see why.

INTERNAL CONFLICT FROM OPPOSITELY IMPRINTED GENES

Just as conflict between individuals sets the context for deception between them (including self-deception), so conflict within the individual sets the stage for deception between its competing parts—something we might call “selves-deception,” which may involve different parts of the brain. The neocortex is largely the social brain, differentially involved in interactions with close relatives and other social relationships; the hypothalamus is involved in hunger and growth, much more egocentric motives. One can well imagine an argument between the two, with the (maternal) neocortex saying, “Family is important; I believe in family; I will invest in family,” while the (paternal) hypothalamus replies, “I’m hungry.” That is, each argues for its favored position as if arguing for the good of the entire organism (“I”).

And there can be no doubt that the requisite genetic variability is available. It is a striking discovery regarding imprinted genes (in mice, at least) that more than half of them affect neural development and later adult behavior. Work is still in its infancy, but here is one striking example. In mice,
paternally
active genes in females are especially important in directing maternal behavior. A few paternally active genes in adult females mediate such important maternal activities as retrieving the pups, licking them, and huddling over them to transfer heat. Sound like a paradox? Not really. Absent inbreeding, the two kinds of genes in a female—maternal and paternal—have the same chance of showing up in her progeny, so no bias is expected on this basis. But females also invest in their sisters’ progeny and other relatives, and they are more closely related to these on their maternal side, so such genes are more likely to compromise on personal reproduction, saving some investment for others, while paternal genes will emphasize investment in their offspring.

Or consider a young woman contemplating whether to enjoy a sexual adventure with her cousin (let us say, the son of her father’s sister). Her paternal genes will at once see an increase in relatedness to any resulting progeny, from one-half to five-eighths (the upside to inbreeding), while maternal genes will see no increase in relatedness at all—but both sets of genes will suffer the resulting decrease in quality of the offspring due to increased genetic homogeneity (the downside to inbreeding). In short, paternal genes in her are more likely to seek out the sexual relationship and maternal ones to resist it. The first declares that “kissing cousins are cute”; the other speaks moralistically about the dangers of defective young via inbreeding. To the individual, this may be experienced as internal argumentation, without any necessary resolution and with each side tempted to overstate its case.

Imagine also a possible society-wide effect. Imagine a patri-local society, in which a woman moves into her husband’s village at marriage, rarely if ever to return to her village of origin. This is common in rural India and many other parts of the world. All of her children will grow up in a world in which they are more related to most surrounding individuals on their paternal side and not their maternal one (mother and full siblings excepted). Thus, growing up in such societies, youngsters are expected to experience internal conflict between their two genetic selves over behavior affecting others. Altruistic behavior that will increase inclusive fitness of paternal genes will not necessarily do so for maternal ones, and so forth. Sons are destined to remain in this patri-local world while daughters will, like their mothers, migrate to other villages, so sons should be especially conflicted. The mother, in turn, will support the maternal genes in her sons, urging sons especially to be less kin-group oriented than the rest of his genes (and his father) might wish.