AI quiz split_6-10.pdf

8 PRObLEMS OF KiNShiP (Chagnon, 1981; Chagnon & Bugos, 1979). Furthermore, a “real abawa” is far more likely to come to a Yanomamö villager’s aid in a social confict, such as an axe fght with a rival individual or a rival group (Alvard, 2009). In short, although kin terms difer somewhat from cultu...

8 PRObLEMS OF KiNShiP (Chagnon, 1981; Chagnon & Bugos, 1979). Furthermore, a “real abawa” is far more likely to come to a Yanomamö villager’s aid in a social confict, such as an axe fght with a rival individual or a rival group (Alvard, 2009). In short, although kin terms difer somewhat from culture to culture, people everywhere seem keenly aware of who are their real kin. A fnal implication of inclusive ftness theory is that kinship terms will be used to persuade and infuence other people, even when no actual kinship is involved. Consider the panhandler’s request: “Hey, brother, can you spare some change?” Precisely why does the panhandler frame the request in this manner? One hypothesis is that he or she is using the kin term “brother” to activate the psychology of kinship in the target. Because we would be more likely to help a brother than a total stranger, the use of the term “brother” might in some small way trigger the psychology of kinship and hence increase the odds of our actually giving spare change. Similar forms of kin term usage are heard in college fraternities and sororities, in which members refer to each other as “brothers” and “sisters.” Soldiers sharing combat often refer to each other as “brothers in arms.” In sum, the invocation of kinship through language is a predicted strategic implication of inclusive ftness theory. Empirical Findings That Support the Implications of Inclusive Fitness Theory The psychology of kinship, although still in its infancy, has received increasing attention in the scientifc literature. Alarm Calling in Ground Squirrels When Belding’s ground squirrels detect a terrestrial predator, such as a badger or a coyote, they sometimes emit a high-pitched staccato whistle, an alarm call alerting other ground squirrels to danger. The alerted squirrels then scramble to safety and avoid being picked of by the predator. The alerted squirrels clearly beneft from the alarm call because it increases their odds of survival, but the alarm caller sufers. Predators are more likely to home in on the alarm caller for their meal. How can we account for this puzzling fnding, which is contrary to individual survival? Several hypotheses have been advanced to explain this apparent act of altruism (Alcock, 2009): 1. The predator confusion hypothesis: The alarm call might function to confuse the predator by creating a mad scramble, in which all the ground squirrels rush around for safety. This confusion might help the squirrels, including the alarm caller, to escape. 2. The parental investment hypothesis: Although the alarm caller is placed at greater risk by sounding the signal, perhaps children are more likely to survive as a result. In this way, the alarm call might function as a form of parental investment. 3. Inclusive ftness hypothesis: Although the signaler might sufer premature death, the squirrel’s aunts, uncles, brothers, sisters, father, mother, and cousins all beneft. According to this hypothesis, the signal alerts the “vehicles” that contain copies of the squirrel’s genes, providing an inclusive ftness beneft. To test these hypotheses, biologist Paul Sherman spent many summers in the California woods painstakingly marking, tracking, and studying an entire colony of Belding’s ground squirrels (Sherman, 1977, 1981). Sherman was able to rule out the frst hypothesis quickly. Sounding the alarm indeed puts the signaler at great risk because predators (weasels, badgers, and coyotes) stalked and killed alarm callers at a far higher rate than non-calling squirrels in the vicinity. So predators are not confused by the alarm call (hypothesis 1); instead, they home in on the alarm caller directly. 223 224 ChALLENGES OF PARENTiNG AND KiNShiP This leaves us with only two hypotheses: the parental investment hypothesis and the inclusive ftness hypothesis. When male Belding’s ground squirrels mature, they leave home and join nonrelated groups. Females, on the other hand, remain with their natal group and so are surrounded by aunts, nieces, sisters, daughters, and other female relatives. It turns out that females give alarm calls far more often than males do—approximately 21 percent more often. This fnding, taken alone, is consistent with both the parental investment hypothesis and the inclusive ftness hypothesis because both daughters and other genetic relatives of the alarm caller beneft from the signal. The critical test comes with female ground squirrels that do not have daughters or other children around but do have other genetic relatives in the vicinity. Do they still alarm call when they spot a predator? The answer is yes. Females without their own children still sound the alarm, as long as they have sisters, nieces, and aunts in the area. In sum, although parental investment is likely to be one function of the alarm calls, the inclusive ftness hypothesis is also supported because females alarm call even when their own children are not around. Female ground squirrels also rush to the aid of genetic relatives—their sisters as well as their daughters— to assist them in territorial conficts with invaders but will not help nonrelatives in such conficts (Holmes & Sherman, 1982). These fndings support the hypothesis that altruism can evolve through the process of inclusive ftness. Kin Recognition and Kin Classifcation in Humans Providing aid to kin requires frst having the ability to recognize them (Weisfeld, Czilli, Phillips, Gall, & Lichtman, 2003). Early association—exposure to kin in infancy—is a key cue that primates use. Association during childhood in human also produces subsequent sexual aversion, functioning as an incest-avoidance adaptation (Lieberman et al., 2007; Shepher, 1971). Another kin recognition mechanism for which there is solid empirical support is based on odor: We can detect kin by smell. Mothers, fathers, grandparents, and aunts all can identify the odor of a newborn kin by smelling a shirt worn by that newborn, although women are better at it than men (Porter, Balogh, Cernoch, & Franchi, 1986). Newborns who were breastfed prefer the odor of their mothers to other women but do not prefer the odors of their fathers to other men (Cernoch & Porter, 1985). Finally, preadolescent children can correctly identify their full siblings by odor but fail to correctly identify their half siblings or stepsiblings (Weisfeld et al., 2003). Another method humans use to identify kin is through kin terminology. All cultures have kin classifcation systems—specifc terms that describe types of kin such as mother, father, sister, brother, uncle, aunt, nephew, niece, and grandmother. Cultures difer somewhat in the particular kin included within a kin term. The English language lumps mother’s sister and father’s sister with the single term “aunt,” for example, whereas other languages have two separate terms for these diferent individuals. Despite this surface variability, Doug Jones has identifed a “universal grammar” governing all systems of kin classifcation (Jones, 2003a, 2003b). This grammar consists of three innate “primitives” of social cognition: genealogical distance, social rank, and group membership. Genealogical distance refers to how close (e.g., parents and siblings) or distant (second-degree or third-degree cousins) the kin are. Social rank refers to relative age, with the older being more highly ranked than the younger. Group membership distinguishes diferent clumps of kin, such as maternal versus paternal kin or same-sex versus opposite-sex siblings. Jones proposes that these three innate primitives are the cognitive building blocks used to generate terms for kin in all cultures. The adaptive value of the genealogical distance building block is based on the logic of inclusive ftness theory. It provides a means for identifying individuals of diferent “kinship value” to us—those from whom we are likely to receive altruism and those to whom we might channel our altruistic acts. The adaptive value of the social rank building block comes from the fact that highranking individuals such as parents are able to provide more help than low-ranking individuals such as children. This allows us to identify potential givers and receivers of altruism. The adaptive 8 PRObLEMS OF KiNShiP value of the group membership building block difers depending on the groups identifed. We may wish to treat same-sex siblings diferently from opposite-sex siblings, for example. Another cue to kinship is physical similarity or phenotypic resemblance, such similarity between your face or body and the faces and bodies of others. Evidence supports the hypothesis that people do indeed use facial resemblance as a cue to kinship relatedness (Bressan & Zucchi, 2009; Park, Schaller, & van Vugt, 2008; Platek & Kemp, 2009). Kin recognition even appears to be linked to negative cues of genetic relatedness; faces that are especially dissimilar to one’s own are seen as especially untrustworthy (Krupp, DeBruine, Jones, & Lalumière, 2012). Can humans also detect kinship among strangers or groups of other people to whom they are not related? Evidence suggests they can—also based on facial resemblance (Alvergne et al., 2008; Kaminski, Dridi, Graf, & Gentaz, 2009). Interestingly, the upper part of the face seems to be especially important for kinship cues. When the lower half of the face was masked, performance on a kin recognition task decreased by only 5 percent (Maloney & Dal Martello, 2006). When the upper half of the face was masked, however, performance on the kin recognition task declined by 65 percent. The ability to detect kinship clusters in others might be critical for solving important adaptive problems: (1) Knowing who is likely to be allied with whom if hostilities break out; (2) who not to antagonize because they have formidable kin in close proximity; and (3) who might be “exploitable” because they have few kin protectors nearby (Buss & Duntley, 2008). In sum, humans have at least four ways of identifying kin: (1) through association; (2) through odor; (3) through kin classifcation generated by a universal grammar of three cognitive building blocks; and (4) through facial similarity or phenotypic resemblance. People are also skilled at detecting kinship among other people they do not know. Kin recognition mechanisms are necessary adaptations on which many subsequent classes of behavior rely: Who will make good coalitional allies, who to trust, who not to have sex with (inbreeding avoidance), and who to help in times of need. Kinship is a fundamental social category, much like sex and age, that people use to carve up their social world because it provides guidance to adaptive action such as altruistic and self-sacrifcing behavior (Lieberman, Oum, & Kurzban, 2008). Patterns of Helping in the Lives of Los Angeles Women Researchers studied helping among 300 adult women from Los Angeles, ages 35 to 45. The following are reasons given by these women for receiving help: When I needed money to get into the union; When I broke my collarbone and he took over the house; Talking to a friend about her marital problems; Picking up a friend’s kids the whole time she was sick; When my son was in trouble with the police; She kept the children when my third child was born; When her husband left her; When she had a leg amputated; Loaned us money for a house down-payment. (Essock-Vitale & McGuire, 1985, p. 141) The women described 2,520 instances of receiving help and 2,651 instances of giving help. The predictions: (1) Among kin, helping will increase as a function of genetic relatedness; and (2) among kin, helping will increase as the recipient’s reproductive value increases. The percentage of instances of helping fall into three diferent categories of kinship: 50 percent genetic overlap, 25 percent genetic overlap, and less than 25 percent genetic overlap (e.g., frst cousin). As predicted, helping exchanges were more likely to occur with close kin than with distant kin. The total percentage of instances of helping involving kin, however, was only about a third. Many acts of helping were received from and directed toward close friends—a topic that we will consider in Chapter 9. The second prediction was that helping among kin will be preferentially channeled to those of higher reproductive potential, a prediction also supported. Women were far more likely to help their children, nieces, and nephews than vice versa. Acts of helping fow from the older to the younger, refecting the greater future reproductive potential of the younger recipients. 225 ChALLENGES OF PARENTiNG AND KiNShiP 226 These fndings are limited in a variety of ways. They are restricted to one sex (women), one city (Los Angeles), and one method of information gathering (questionnaire). As we will see, however, kinship exerts a powerful efect on helping when the sample is extended to men, to diferent populations, and to diferent methodologies. One study found that both men and women in Great Britain spent more money on Christmas presents for close rather than distant kin (Dyble, van Leeuwen, & Dunbar, 2015). Another study of 11,211 South African households discovered that the degree of genetic relatedness predicted how much money was spent on children’s food, health care, and clothing (Anderson, 2005). And a study of the Pimbwe—a Tanzanian horticultural population—found that the larger the size of the maternal kin network, the healthier the children and the lower their mortality rate (Hadley, 2004). Life-or-Death Helping Among Humans One study explored hypotheses derived from inclusive ftness theory (Burnstein, Crandall, & Kitayama, 1994). Specifcally, the researchers hypothesized that helping others will be a direct function of the recipient’s ability to enhance the inclusive ftness of the helper. Helping should decrease, they reasoned, as the degree of genetic relatedness between helper and recipient decreases. Helping should be greater among siblings (50 percent relatedness) than between a person and his or her sibling’s children (25 percent relatedness). Helping should be lower still between frst cousins (12.5 percent). No other theory in psychology predicts this precise helping gradient. Genetic relatedness is not the only theoretical consideration. Helping should decrease as a function of the age of the recipient, all else equal, since helping an older relative will have less impact on one’s ftness than will helping a younger relative because the latter is more likely to produce ofspring that carry some of the same genes. Moreover, genetic relatives higher in reproductive value and those who ofer a better return on one’s investment should be helped more than those of lower reproductive value and those who ofer a lower return. In studies to test these hypotheses, researchers distinguished between two types of helping: (1) helping that is substantial, such as acts that afect whether the recipient will live or die; and (2) helping that is relatively trivial, such as giving someone a little spare change. The predicted patterns of altruism should be stronger under the frst type than the second. To test these hypotheses, Burnstein and colleagues studied two diferent cultures: the United States and Japan. Participants responded to questions about what they would do in a scenario in which a house was rapidly burning and they only had time to rescue one of the three people in the house. The researchers stressed that only the person who received help would survive—all others would perish. In the less signifcant form of everyday helping, people evaluated scenarios of which people they would help by picking up a few small items from a store. Recipients of the help varied in degree of genetic relatedness to the helper. Helping in these hypothetical scenarios decreased steadily as the degree of genetic relatedness decreased. The .50 sibling was helped more than the .25 relatives, who in turn were helped more than those with only .125 genetic relatedness. This result proved especially strong in the life-ordeath scenario. Helping in the life-or-death situation also declined steadily as the potential recipient’s age increased. One-year-olds were helped more than 10-year-olds, who in turn were helped more than 18-year-olds. Least helped were the 75-year-olds. Interestingly, the efects of age on helping were strongest in the life-or-death situation but actually reversed in the trivial helping condition. For everyday helping such as running an errand, people helped the 75-year-olds somewhat more than the 45-year-olds (see Figure 8.1). These fndings replicated well across both Japanese and U.S. samples. A study in Taiwan also found that genetic relatedness predicted helping, with the 8 PRObLEMS OF KiNShiP 227 Figure 8.1 Tendency to Help as a Function of Recipient’s Age Under Life-or-Death Versus Everyday Conditions Source: Burnstein, E., Crandall, C., & Kitayama, S. (1994). Some neo-Darwinian decision rules for altruism: Weighing cues for inclusive ftness as a function of the biological importance of the decision. Journal of Personality and Social Psychology, 67, 779. Copyright © 1994 by the American Psychological Association. Reprinted with permission. most help being given to genetic relatives who were highest in reproductive value (Chuang & Wu, 2017). Although scientists obviously cannot do experiments where life or death is literally at stake, a naturalistic study of killing among Icelandic Vikings provided some compelling evidence that kin count (Palmstierna, Frangou, Wallette, & Dunbar, 2017). The researchers predicted that the presence of a large kin network would ofer protection against getting lethally attacked by others. Using data from Icelandic family sagas, researchers found that the more biological kin and afnal kin (in-laws) one had, the lower the likelihood of being killed by other groups. In contrast, having very few kin increased the likelihood of getting killed. Kin apparently count when it comes to killing and protection from being killed. Fitzgerald and Colarelli (2009) found that genetic relatedness predicted helping but only when the altruism was extraordinary or life threatening. People help healthy kin more than those with reproductive limitations, such as having schizophrenia. Kinship predicts helping in hypothetically highly risky situations, such as fghting of attackers or defending against dangerous predators (Fitzgerald & Whitaker, 2009). Another study found that although people gave as much or more help to friends and mates as to a sibling, as the cost of the help escalated, people gave increasing amounts of help to siblings and decreasing amounts of help to mates and friends (Stewart-Williams, 2008). This fnding is particularly interesting in light of the fact that participants reported feeling emotionally closer to their mates and friends than to their siblings! Yet another study of 7,265 individuals from the Netherlands found that people received more investment from their full siblings than from their half siblings, even when the half siblings were raised together and treated by parents as if they were full siblings (Pollet, 2007). People even respond with more aggression toward those who verbally insult their kin than non-kin (Gesselman & Webster, 2012). When it really matters, kinship apparently exerts a powerful efect on altruism. Kinship has a strong infuence over sharing food resources in many cultures. Studies of the horticulturalists of Nicaragua and the Hadza of Tanzania show that good hunters ensure that their bounty of meat is distributed to households containing their close kin (Koster, 2011a; Wood & Marlowe, 2013). In the fshing and whaling villages of Indonesia, kinship is the strongest predictor of food sharing (Nolin, 2011). Among the Saami reindeer herders of Norway, having large groups of herders containing high levels of genetic relatedness resulted in larger and more efciently used herds, which function to provide milk, meat, and clothing (Næss, Bårdsen, Fauchald, & Tveraa, 2010; Næss, Bårdsen, & Tveraa, 2012). The benefts of having kin in close proximity may be especially pronounced for women. A study of the Himba, a group of seminomadic African pastoralists, found that women strive