AI quiz split_11-16.pdf

ChALLENGES OF PARENTiNG AND KiNShiP 228 to maintain kin contact, even if they move in with their husband’s family after marriage (Scelza, 2011). They continue to visit and spend time with their kin after marriage; they tend to return to stay with their kin around the time they give birth; and a di...

ChALLENGES OF PARENTiNG AND KiNShiP 228 to maintain kin contact, even if they move in with their husband’s family after marriage (Scelza, 2011). They continue to visit and spend time with their kin after marriage; they tend to return to stay with their kin around the time they give birth; and a divorce or death of a spouse triggers a return to living with their kin. And a study in Thailand found that living with kin has positive efects on contributors to fertility such as a short interbirth interval (Snopkowski & Sear, 2013). Genetic Relatedness and Emotional Closeness: Is Blood Thicker Than Water? The Burnstein studies demonstrate clearly that genetic relatedness strongly afects helping, especially in life-or-death situations. Unexplored, however, are the underlying psychological mechanisms that motivate helping. In an efort to fll this gap, two theorists have proposed that “emotional closeness” is a psychological mediator. In one study, participants indicated how emotionally close they felt to each family member, ranging from 1 (not at all close) to 7 (extremely close) (Korchmaros & Kenny, 2001). Subsequently, they completed procedures similar to the Burnstein procedures for helping in hypothetical situations. As in the Burnstein studies, they found that genetic relatedness predicted willingness to act altruistically. But the key new fndings centered on emotional closeness. Not only were individuals more likely to be emotionally close to their family members who were the most genetically related to them, but emotional closeness also statistically mediated the tendency to behave altruistically toward their family members. A larger study of 1,365 participants in Germany found similar results (Neyer & Lang, 2003), as have other studies (Korchmaros & Kenny, 2006; Kruger, 2003). Genetic relatedness proved to be a strong predictor of subjective closeness, a correlation between the two variables being a whopping +.50. These efects proved to be robust even when statistically controlling for variables such as residential proximity and frequency of contact; that is, people feel psychologically close to those who are highly genetically related even if they live far away and rarely see them. Two other indications of emotional closeness are the frequency of contact and doing favors. Both are linked to genetic relatedness (Kurland & Gaulin, 2005). Full siblings, for example, have more frequent contact with each other than do half siblings, stepsiblings, or cousins. And the recency of doing a favor for these individuals falls out in the same order, with most favors done for full siblings and fewest favors for cousins. Yet another indication of emotional closeness is the amount of psychological grief various relatives experience when a child dies. Parents experience more grief than relatives who are less genetically close (Littlefeld & Rushton, 1986). Interestingly, the death of an elder child causes more intense grief than the death of a younger child; and the death of a healthy child causes more grief than the death of a sickly child. In summary, emotional closeness might be one underlying psychological mechanism that prompts acts of altruism toward genetic relatives, although future research will undoubtedly uncover other mechanisms. Blood, as the saying goes, might indeed be thicker than water. Vigilance Over Kin’s Romantic Relationships As we know from Chapters 4, 5, and 6, humans have many mating adaptations because mating is so close to the engine of the evolutionary process—diferential reproductive success. Because of the critical importance of success in the mating game, it would be surprising if individuals were indiferent to the mating relationships of their kin. A study tested two hypotheses: (1) Individuals will maintain greater vigilance over the mating relationships of their close than distant kin; and (2) individuals will maintain greater vigilance over the mating of their female than male kin (Faulkner & Schaller, 8 PRObLEMS OF KiNShiP 2007). Results supported both hypotheses using three dependent measures: awareness of the romantic partner’s good and bad qualities, awareness of how the romantic relationship was progressing, and the degree to which they worried about how the romantic relationship was progressing. Another study in lowland Nicaragua found that both male and female kin of a woman expressed strong preferences for a prospective husband who both was wealthy and displayed good hunting abilities (Koster, 2011b). In sum, degree of genetic relatedness and sex of target both afect the degree to which individuals maintain vigilance over their kin’s romantic relationships. 8.1 Infdelity All in the Family: A Kin Hypothesis Refuted Two evolutionary psychologists generated what appeared on the surface to be an obvious implication of inclusive ftness: If one’s romantic partner commits sexual infdelity with one’s genetic relative, the subjective distress would be less than if the infdelity occurred with a stranger (Kostic & Yadon, 2014). Their reasoning was that if a man’s wife, for example, got impregnated by the man’s brother, then the inclusive ftness costs of the infdelity would be less than if she were impregnated by a stranger. At least some of the victim’s genes would still get passed on through the brother but none through the stranger. Two experiments refuted this hypothesis. When considering hypothetical infdelity scenarios, people reported that they would actually feel worse if their partner cheated on them with a biological relative than with a stranger, contrary to predictions. The authors ofer several possible explanations. One is that a partner’s infdelity with a biological relative constitutes a double betrayal—a betrayal by one’s mate but also a betrayal by a trusted ally such as a brother. Another explanation might be that a partner’s infdelity with one’s biological relative may have been sufciently rare over human evolutionary history that selection failed to fashion an adaptation that relaxed emotional upset in response to it. The authors appropriately state that Hamilton’s theory specifes the conditions under which adaptations could evolve but does not guarantee that adaptations will necessarily evolve in all specifc circumstances, in this case a relaxation of upset if a partner’s infdelity occurs with a genetic relative. These studies also provide a nice illustration of the fact that evolutionary psychological hypotheses that generate specifc predictions can be tested, are sometimes confrmed empirically, and are sometimes refuted or falsifed by empirical studies. Kinship and Stress Stressful situations cause the release of the hormone cortisol into the bloodstream. Cortisol has several functions, including releasing energy for action and afecting mental activity such as degree of alertness (Flinn, Ward, & Noone, 2005). The benefts of cortisol production in dealing with the immediate source of the stress, however, come at a cost. Cortisol tends to inhibit growth and hinder reproductive function. Cortisol produced by prolonged stress can damage body organs and reproductive functioning. Mark Flinn and colleagues monitored cortisol levels through saliva samples in a sample of children residing in a Caribbean village (Flinn et al., 2005). Children living in nuclear families with both parents present showed the lowest levels of cortisol. Children living only with a single mother showed elevated cortisol levels, but if other close kin were also living in the house, the children’s cortisol levels were lower. Children in households with a stepfather and half sibs and households with distant relatives showed the highest levels of cortisol. The links between household composition and cortisol levels could be due to several factors (Flinn et al., 2005). Children living in difcult caretaking environments, such as those with stepfathers, half siblings, or distant relatives, could experience more frequent stressful events, such as fghting between parents, punishment by parents or stepparents, or more confict with half siblings. Or perhaps difculties earlier in their lives may impair coping abilities in dealing with the current stressors. Whatever the precise causal paths turn out to be, these results highlight the importance of close kin in creating less stressful environments and also indicate the stress to which kids are exposed without kin around. 229 ChALLENGES OF PARENTiNG AND KiNShiP 230 Kinship and Survival Emotional closeness and responses to hypothetical life-or-death scenarios is one thing. Actual survival is another. Is there any evidence that having kin in close proximity afects actual survival rates during real life-or-death situations? Two studies have explored this possibility. One was conducted of the survivors of the Mayfower pioneers in Plymouth Colony during the early years of the settling of America (McCullough & York Barton, 1990). Food was in short supply and diseases were rampant during the frst cold winter of 1620–1621. Of the 103 frst pioneers, a full 51 percent died. A large predictor of who lived and who died was simply the number of genetic relatives in the colony. Those who were most likely to die had the fewest relatives. Those who were most likely to live had parents and other relatives both in the colony and among the survivors. Similar results have been documented in other life-or-death situations, such as during the Donner Party disaster of 1846, in which 40 out of 87 people died during a bitter winter (Grayson, 1993). In studies of natural fertility populations, mothers and maternal grandmothers have an especially pronounced infuence on the survival of children (Sear & Mace, 2008). A study of rural Malawi found that having older siblings of either sex is linked with higher survival rates (Sear, 2008). During evolutionary bottlenecks, when life is literally on the line, genetic relatives exert a strong infuence on the odds of survival. Patterns of Inheritance—Who Leaves Wealth to Whom? Another domain for testing inclusive ftness theory centers on the inheritance of wealth. When a person writes a will identifying benefciaries, can the pattern of distribution be predicted from inclusive ftness theory? Smith, Kish, and Crawford (1987) tested three predictions about patterns of inheritance: (1) People will leave more of their estates to genetically related kin and spouses than to unrelated people. The inclusion of spouses in the prediction occurs not because of genetic relatedness but rather because presumably the spouse will distribute the resources to their mutual children and grandchildren. (2) People will leave more to close kin than to distantly related kin. (3) People will leave more to ofspring than to siblings, even though the average genetic relatedness is the same in these two types of relationships. One’s ofspring, generally being younger than one’s siblings, will on average have higher reproductive value. At the time in the life span when wills typically go into efect, siblings are likely to be past their childbearing years, whereas children are more likely to be able to convert resources into future ofspring. To test these predictions, researchers studied the bequests of 1,000 randomly selected decedents, 552 men and 448 women, from the Vancouver region of British Columbia, Canada. Researchers recorded the total dollar value of each estate, as well as the percentage willed to each benefciary. The average estate was $54,000 for men and $51,200 for women. Interestingly, women tended to distribute their estates to a larger number of benefciaries (2.8) than did men (2.0). The frst prediction was soundly confrmed. People left only 7.7 percent of their estates, on average, to nonrelatives and 92.3 percent to spouses or kin. The second prediction was also confrmed. Decedents willed more of their estates to closely related genetic kin than to more distant genetic relatives. Considering only the amount left to kin (excluding spouses and nonkin), people left 46 percent of their estates to relatives sharing 50 percent of their genes, 8 percent to relatives sharing 25 percent of their genes, and less than 1 percent to relatives sharing only 12.5 percent of their genes. These data support the hypothesis that selection has fashioned psychological adaptations of resource allocation that favor close genetic relatives. The third prediction—that people would bequeath more to children than to siblings—also was confrmed. Indeed, people left more than four times as much to their children (38.6 percent of the total estate) as to their siblings (7.9 percent of the estate). An analysis of 1,000 wills from British 8 PRObLEMS OF KiNShiP Columbia replicated these results, and also found support for all three predictions (Webster, Bryan, Crawford, McCarthy, & Cohen, 2008). In another analysis of wills, Debra Judge (1995) replicated the fnding that women tend to distribute their estates among a larger number of benefciaries. A majority of men tended to leave their entire estates to their wives, often with expressed confdence that the wife would pass along the resources to their children. Here are a few examples of the reasons men included in their wills for channeling all of their resources to their wives: knowing her [wife] to be trustworthy and that she will provide for my boys . . . their education and a start in life no provision for my children . . . for the reason that I know she [wife] will make adequate provision for them [wife] can handle the estate to better advantage if the same be left wholly to her and . . . [have] confdence she will provide for her said children as I would have done. (Judge, 1995, p. 306) In sharp contrast, women who were married when they died did not express such trust. Indeed, when a husband was mentioned at all, it was often with a qualifcation. For example, six women intentionally excluded their husbands from their wills because they were abandoned by the husband, “for reasons sufcient [or ‘best known’] to me,” or because of statements about the husband’s “misconduct.” In one case, a woman left her entire estate to her husband “as long as he lives unmarried” (Judge, 1995, p. 307). Older men are far more likely than older women to remarry (Buss, 2016b). Therefore, widowers might use their previous wife’s resources to attract a new mate and perhaps even start a new family. Resources will be diverted from the original wife’s children to unrelated individuals. In contrast, because older women are unlikely to marry and even more unlikely to have additional children (most will be post-menopausal), the husband can be more confdent that his widow will allocate the resources toward their mutual children. A pair of studies conducted in Germany supported these interpretations (Bossong, 2001). Men and women of varying ages were asked to imagine that a doctor had told them that they were terminally ill and so had to write a will to allocate their resources across children and spouse. Women were more likely than men to allocate resources directly to their children. Men were more likely to allocate resources to their surviving spouse. However, the age of the surviving spouse mattered a lot to men. If their surviving spouse was old and post-reproductive, then men were likely to allocate the lion’s share to her, presumably because she would then distribute it to their children. If their surviving spouse was young, however, and hence likely to remarry and possibly have more children fathered by another man, men were less likely to leave their money to their spouses, choosing instead to leave it directly to their children. In summary, genetic relatives are bequeathed more than nonrelatives. Close kin receive more than distant kin. Direct descendants, primarily children, receive more than collateral kin such as sisters and brothers. Given the fact that formal wills are relatively recent inventions, how can we interpret these fndings? It is certainly not necessary to postulate a specifc “willmaking adaptation,” because wills are too recent to have constituted a recurrent feature of our environment of evolutionary adaptedness. The most reasonable interpretation is that humans have evolved psychological mechanisms of resource allocation, that genetic relatedness is a pivotal factor in the decision rules of resource allocation, and that these evolved mechanisms operate on a relatively recent type of resources, those accumulated during one’s life in the form of tangible assets that can be distributed in the form of wills. Investment by Grandparents The past century has witnessed the gradual erosion of the extended family, as increased mobility has spread family members apart. Despite this departure from the extended kin contexts in which humans evolved, the relationship between grandparents and grandchildren appears to have retained a place of importance (Coall & Hertwig, 2010; Euler & Weitzel, 1996). 231 232 ChALLENGES OF PARENTiNG AND KiNShiP You might think that becoming a grandparent would be marked by great sorrow, a signal of old age and impending death. In fact, precisely the opposite is true. The arrival of grandchildren heralds a time of pride, joy, and deep fulfllment (Fisher, 1983). We have all experienced our elders proudly showing of photographs and memorabilia from the lives of their grandchildren or had to endure long-winded tales of the grandchildren’s accomplishments. There is tremendous variability, however, in how close to or distant from their grandparents grandchildren are. With some, the emotional bond is marked by warm feelings, frequent contact, and heavy investment of resources. With others, the feelings are distant, contact infrequent, and investment of resources rare. Evolutionary psychologists have turned to explaining variability in grandparental investment. In humans, grandparents ofen invest in their grandchildren and show Theoretically, grandparents are relationships marked by warmth, frequent contact, and devotion. Specifc genetically related by .25 to each patterns of grandparental investment are predictable from theories of grandchild. So on what basis could we paternity uncertainty developed by DeKay (1995) and Euler and Weitzel generate predictions about diferences (1996). in grandparents’ investment? Recall a profound sex diference that has cropped up several times: Men face the adaptive problem of paternity uncertainty, whereas women are 100 percent certain of their maternity. This applies to grandparents as well as to parents, but there is a special twist on the theory: We are dealing with two generations of descendants, so from a grandfather’s perspective, there are two opportunities for genetic kinship to be severed (DeKay, 1995). First, it is possible that he is not the genetic father of his son or daughter. Second, his son might not be the father of the putative grandchildren. This double whammy makes the blood relationships between a grandfather and his son’s children the most uncertain of all grandparental relationships. At the other end of the certainty continuum are women whose daughters have children. In this case, the grandmother is 100 percent certain that her genes are carried by her grandchildren (keep in mind that none of this need be conscious). She is undoubtedly the mother of her daughter, and her daughter is certain of her genetic relatedness to her children. In sum, the theoretical prediction from the inclusive ftness theory is clear: From the grandchild’s perspective, the mother’s mother (MoMo) should invest the most and the father’s father (FaFa) should invest the least, all else being equal. What about the other two types of grandparents: the mother’s father (MoFa) and the father’s mother (FaMo)? For each of these cases, there was one place in the line of descent where relatedness could be severed. A man whose daughter has a child might not be the actual father of his daughter. A woman with a son might not be related to her son’s children. 8 PRObLEMS OF KiNShiP 233 The investment of these two types of grandparents, therefore, is predicted to be intermediate between the most certain genetic linkage (MoMo) and the least certain genetic linkage (FaFa). The investment that a person makes in grandchildren can take many forms, both behavioral and psychological. Behaviorally, one could examine frequency of contact, actual investment of resources, readiness to adopt, or the willing of property. Psychologically, one could examine expressed feelings of closeness, magnitude of mourning on the death of a grandchild, and willingness to make sacrifces of various sorts. The hypothesis of “discriminative grandparental investment” predicts that behavioral and psychological indicators of investment should follow the degree of certainty inherent in the diferent types of grandparental relationships: most for MoMo, least for FaFa, and in between these two for MoFa and FaMo. Studies from diferent cultures have tested the hypothesis of discriminative grandparental solicitude. In one study conducted in the United States, evolutionary psychologist Todd DeKay (1995) studied a sample of 120 undergraduates. Each student completed a questionnaire that included information on biographical background and then evaluated each of the four grandparents on the following dimensions: grandparent’s physical similarity to self, grandparent’s personality similarity to self, time spent with grandparent while growing up, knowledge acquired from grandparent, gifts received from grandparent, and emotional closeness to grandparent. Figure 8.2 summarizes the results from this study. Findings show that the mother’s mother is closer to, spends more time with, and invests most resources in the grandchild, whereas father’s father scores lowest on these dimensions. Findings presumably refect evolved psychological mechanisms sensitive to the degree of certainty of genetic relatedness. Another interesting pattern emerged for the two grandparents of intermediate relational uncertainty. In each case, for all four variables, the mother’s father was ranked higher than the father’s mother. How can this pattern be explained, since in each case there is one opportunity for the genetic link to be severed? DeKay (1995) had actually predicted this fnding in advance by suggesting that infdelity rates were higher in the younger generation than in the older generation—a suggestion that has some empirical support (Laumann, Gagnon, Michael, & Michaels, 1994). Thus, the relational uncertainty would be higher for the father’s mother, since Figure 8.2 Grandparental Investment in Grandchildren Source: DeKay, W. T. (1995, July). Grandparental investment and the uncertainty of kinship. Paper presented to Seventh Annual Meeting of the Human Behavior and Evolution Society, Santa Barbara. Reprinted with permission. The lefmost panel shows the rankings of subjects’ emotional closeness to each of their grandparents. Participants indicated the most emotional closeness to their mother’s mother and the least emotional closeness to their father’s father. A similar pattern emerged for the variables of time spent with the grandparent and the resources (gifs) they received from the grandparent.