Evolutionary Psychology PDF - Chapter 4

112 ChALLENGES OF SEx AND MATiNG needs. They tend to be verbally and physically abusive. They have more afairs than average, suggesting further diversion of time and resources (Buss & Shackelford, 1997a). All these costs reveal that undependable and emotionally unstable men will absorb their partn...

112 ChALLENGES OF SEx AND MATiNG needs. They tend to be verbally and physically abusive. They have more afairs than average, suggesting further diversion of time and resources (Buss & Shackelford, 1997a). All these costs reveal that undependable and emotionally unstable men will absorb their partners’ time and resources, divert their own time and resources elsewhere, and fail to channel resources consistently over time. Dependability and stability are personal qualities that signal increased likelihood that a woman’s own resources will not be drained by the man. Unpredictability interferes with solutions to critical adaptive problems. The erratic supply of resources can wreak havoc with accomplishing the goals required for survival and reproduction. Meat that is suddenly not available because an unpredictable, changeable, or variable mate decided at the last minute to take a nap rather than go on the hunt is sustenance counted on but not delivered. Resources that are supplied predictably can be more efciently allocated to Women prefer men who are relatively tall, athletic, muscular, and the many adaptive hurdles that must display a V-shaped torso, with shoulders broader than hips—signals that be overcome in everyday life. Women indicate a man’s ability to protect a woman and her children. place a premium on dependability and emotional stability to reap the benefts that a mate can provide to them consistently over time. Preference for Athletic Prowess, Formidability, and Height The importance of physical characteristics in the female choice of a mate is notable throughout the animal world. Male gladiator frogs are responsible for creating nests and defending the eggs. In the majority of courtships, a stationary male gladiator frog is deliberately bumped by a female who is considering him. She strikes him with great force, sometimes enough to rock him back or even scare him away. If the male moves too much or bolts from the nest, the female hastily leaves to fnd an alternative mate. Bumping helps a female frog assess how successful the male will be at defending her clutch. The bump test reveals the male’s physical ability to protect. Women sometimes face physical domination by larger, stronger males, which can lead to injury and sexual domination. These conditions undoubtedly occurred with some regularity during ancestral conditions. Studies of many non-human primate groups reveal that male physical and sexual domination of females has been a recurrent part of our primate heritage. Primatologist Barbara Smuts lived among the baboons residing in the savanna plains of Africa and studied their mating patterns (Smuts, 1985). She found that females frequently formed enduring “special friendships” with males who ofered physical protection to them and their infants. In return, these females sometimes granted their “friends” preferential mating access during times of estrus. 4 WOMEN’S LONG-TERM MATiNG STRATEGiES One beneft to women of long-term mating is the physical protection a man can ofer. A man’s size, strength, physical prowess, and athletic ability are cues that signal solutions to the problem of protection. Evidence shows that women’s preferences in a mate embody these cues. Women judge short men to be undesirable for either a short-term or a long-term mate (Buss & Schmitt, 1993). In contrast, women fnd it very desirable for a potential marriage partner to be tall, physically strong, and athletic. A study of women from Britain and Sri Lanka found strong preferences for male physiques that were muscular and lean (Dixon, Halliwell, East, Wignarajah, & Anderson, 2003). Women also prefer and fnd attractive men with a “V-shaped” torso—broad shoulders relative to hips (Hughes & Gallup, 2003). Another good index of physical formidability is handgrip strength (Gallup & Fink, 2018), which may be why men sometimes show of in mate-attraction tactics by volunteering to open the lids on jars that are especially difcult to open (Buss, 1988a). Women who are especially fearful of crime show even stronger preferences for long-term mates who are physically formidable (Snyder et al., 2011). Moreover, women exposed in an experiment to images of men fghting with each other or images of weapons increased their preferences for masculine-looking male faces—likely a cue to protection (Little, DeBruine, & Jones, 2013). Tall men are consistently seen as more desirable as dates and mates than are short or average men (Courtiol, Ramond, Godelle, & Ferdy, 2010; Ellis, 1992). Two studies of personal ads revealed that, among women who mentioned height, 80 percent wanted a man to be 6 feet or taller (Cameron, Oskamp, & Sparks, 1978). Personals ads placed by taller men received more responses from women than those placed by shorter men (Lynn & Shurgot, 1984). Indeed, a study of the “hits” received by 1,168 personal advertisements in Poland found that a man’s height was one of the four strongest predictors of the number of women who responded to the male ads (the others being education level, age, and resources) (Pawlowski & Koziel, 2002). Tall men are perceived as more dominant, are more likely to date, and are more likely to have attractive partners than shorter men (see Brewer & Riley, 2009, for a review). Women solve the problem of protection from other aggressive men at least in part by preferring a mate who has the size, strength, and physical prowess to protect them. These physical qualities also contribute to solutions to other adaptive problems such as resource acquisitions and genes for good health, since tallness is also linked with status, income, symmetrical features, and good health (Brewer & Riley, 2009). Among the Mehinaku tribe of the Brazilian Amazon, anthropologist Thomas Gregor (1985) noted the importance of men’s wrestling skills as an arena in which these diferences become acute: A heavily muscled, imposingly built man is likely to accumulate many girlfriends, while a small man, deprecatingly referred to as a peristsi, fares badly. The mere fact of height creates a measurable advantage. . . . A powerful wrestler, say the villagers, is frightening . . . he commands fear and respect. To the women, he is “beautiful” (awitsiri), in demand as a paramour [lover] and husband. (p. 35) Preference for Good Health: Symmetry and Masculinity Mating with someone who is unhealthy would have posed a number of adaptive risks for our ancestors. First, an unhealthy mate would have a higher risk of becoming debilitated, thus failing to deliver whatever adaptive benefts might otherwise be provided such as food, protection, health care, and investment in childrearing. Second, an unhealthy mate would be at greater risk of dying prematurely, thereby cutting of the fow of resources and forcing the search for a new mate. Third, an unhealthy mate might transfer communicable diseases. Fourth, an unhealthy mate might infect the children of the union, imperiling their chances of surviving and reproducing. And 113 114 ChALLENGES OF SEx AND MATiNG ffh, if health is partly heritable, a person who chooses an unhealthy mate would risk passing on genes for poor health to children. For all these reasons, women and men both place a premium on the health of a potential mate. In the study of 37 cultures, on a scale ranging from 0 (irrelevant) to +3 (indispensable), women and men both judged “good health” to be highly important. Averaged across the cultures, women gave it a +2.28 and men gave it a +2.31 (Buss et al., 1990). An important physical marker of good health is the degree to which the face and body are symmetrical (Gangestad & Thornhill, 1997; Grammer & Thornhill, 1994; Shackelford & Larsen, 1997; Thornhill & Møeller, 1997). Environmental events and genetic mutations produce deviations from bilateral symmetry, creating lopsided faces and bodies. Some individuals are able to withstand such events and stresses better than others—that is, they show developmental stability. The presence of facial and bodily symmetry is an important health cue, refecting an individual’s ability to withstand environmental and genetic stressors. Therefore, women are hypothesized to have evolved a preference for men who show physical evidence of symmetry. Such symmetry would not only increase the odds of the mate being around to invest and less likely to pass on diseases to her children, it may have genetic benefts as well. By selecting a man with symmetrical features, a woman may be selecting a superior complement of genes to be transmitted to her children. Some evidence supports the hypothesis that symmetry is indeed a health cue and that women especially value this quality in mates (Gangestad & Thornhill, 1997; Thornhill & Møeller, 1997). First, facially symmetric individuals score higher on tests of physiological, psychological, and emotional health (Shackelford & Larsen, 1997). Second, there is positive relationship between facial symmetry and judgments of physical attractiveness in both sexes. Third, women judge facially symmetrical men, compared with their more lopsided counterparts, to be more sexually attractive. Facial symmetry is linked to judgments of health (Jones et al., 2001). Men with more symmetrical faces experienced fewer respiratory illnesses, suggesting better disease resistance (Thornhill & Gangestad, 2006). Some researchers, however, question the quality of the studies and conclude that the evidence on the association between symmetry and health is not yet fully convincing (Rhodes, 2006). Another health cue might stem from masculine features. The average faces of adult men and women difer in several fundamental respects. Men tend to have longer and broader lower jaws, stronger brow ridges, and more pronounced cheekbones, primarily as a consequence of pubertal hormones such as testosterone. Victor Johnston and his colleagues developed a sophisticated experimental tool to vary these features, in the form of a 1,200-frame QuickTime movie (Johnston, Hagel, Franklin, Fink, & Grammer, 2001). The computer program allows a person to search through hundreds of faces that vary in masculinity, femininity, and other features. Participants use a slider control and single-frame buttons to move back and forth through the 1,200-frame movie to locate the frame containing the desired target, such as “most attractive for a long-term mate.” Women overall preferred faces that were more masculine-looking than average. A metaanalysis of 10 studies confrmed that masculinity is attractive in male faces, although the efect size is modest (+.35) (Rhodes, 2006). Women also fnd vocal masculinity to be attractive (Feinberg, DeBruine, Jones, & Little, 2008). Why would women fnd masculine-looking males attractive? Johnston argues that masculine features are signals of good health. High levels of testosterone compromise the human immune system. According to Johnston’s argument, only males who are quite healthy can “aford” to produce high levels of testosterone during their development. Less healthy males must suppress testosterone production, lest they compromise their already weaker immune systems. As a result, healthy males end up producing more testosterone and developing more rugged masculine-looking faces. If Johnston’s argument is 4 WOMEN’S LONG-TERM MATiNG STRATEGiES 115 Most women fnd men with symmetrical faces, as exemplifed by the actor Denzel Washington (lef), to be more attractive than men with asymmetrical faces, as illustrated by the musician and actor Lyle Lovett (right). Symmetry is hypothesized to be a health cue that signals a relative absence of parasites, genetic resistance to parasites, or a relative lack of environmental insults during development. © AF archive/Alamy correct, women’s preference for masculine faces is a preference for a healthy male. Support for this hypothesis comes from the fnding that women living in low-health nations have especially strong preferences for facial masculinity (Pisanski & Feinberg, 2013). Moreover, women who are especially sensitive to becoming disgusted by cues to pathogen-causing diseases also show especially strong preferences for masculine male faces (DeBruine, Jones, Tybur, Lieberman, & Giskevicius, 2010). Johnston went through the 1,200-frame QuickTime movie a second time and asked the women to pick out the face they viewed as the “healthiest.” The faces women chose were indistinguishable from their judgments of “the most attractive face,” supporting the theory that masculine appearance might be valued by women because it signals health. Another study found that men with more masculine faces had fewer respiratory diseases, suggesting that it might be a signal of disease resistance (Thornhill & Gangestad, 2006). Other researchers present evidence that women’s attraction to masculine features refects dominance in same-sex competition rather than health (Boothroyd, Jones, Burt, & Perrett, 2007; see also Puts, Welling, Burris, & Dawood, 2012; Scott, Clark, Boothroyd, & Penton-Voak, 2013). Importantly, masculine features are also cues to physical formidability, which would help a woman solve the adaptive problem of protection. ChALLENGES OF SEx AND MATiNG 116 Love and Commitment Women have long faced the adaptive problem of choosing men who not only have the necessary resources but also show a willingness to commit those resources to them and their children. Although resources can ofen be directly observed, commitment cannot. Instead, gauging commitment requires looking for cues that signal future channeling of resources. Love may be one of the key cues to commitment (Buss, 2018b). According to conventional wisdom in the social sciences, “love” is a relatively recent invention, introduced a few hundred years ago by romantic European poets (Jankowiak, 1995). Research suggests that this conventional wisdom is radically wrong. There is evidence that loving thoughts, emotions, and actions are experienced by people in cultures worldwide— from the Zulu in the southern tip of Africa to the Inuit in the cold northern ice caps of Alaska. In a survey of 168 diverse cultures around the world, anthropologists William Jankowiak and Edward Fischer examined four sources of evidence for the presence of love: the singing of love songs, elopement by lovers against the wishes of parents, cultural informants reporting personal anguish and longing for a loved one, and folklore depicting romantic entanglements. They found evidence for romantic love in 88.5 percent of the cultures (Jankowiak, 1995; Jankowiak & Fischer, 1992). Clearly love is not a phenomenon limited to the United States or to Western cultures. To identify precisely what love is and how it is linked to commitment, several studies examined acts of love (Buss, 1988a, 2018b; Wade, Auer, & Roth, 2009). Acts of commitment top women’s and men’s list as most central to love. These acts include giving up romantic relations with others, talking of commitment and marriage, and expressing a desire to have children with this person. When performed by a man, these acts of love signal the intention to commit resources to one woman and her future children. Reports of experiencing love powerfully predict feelings of subjective commitment—far more than reports of sexual desire (Gonzaga, Haselton, Smurda, Davies, & Poore, 2008). The hypothesis that the commitment of paternal care to children is one of the functions of love attains support from a comparative and phylogenetic analysis of diferent species that looked at the links between adult attachment and paternal care (Fraley et al., 2005). Species that exhibited adult attachment were more likely to be characterized by male parental investment in ofspring than species that did not. Thus, one function of the female preference for love in a mate is to ensure the commitment of his parental resources to the children they produce together. One component of commitment is fdelity, exemplifed by the act of remaining faithful to a partner when not physically together. Fidelity signals the exclusive commitment of sexual resources to a single partner. Another aspect of commitment is the channeling of resources to the loved one. Emotional support is another facet of commitment, revealed by being available in times of trouble and listening to the partner’s problems. Commitment entails a channeling of time, energy, and efort to the partner’s needs at the expense of fulflling one’s own personal goals. Acts of reproduction also represent a direct commitment to one’s partner’s reproduction. All these acts, which are viewed as central to love, signal the commitment of sexual, economic, emotional, and genetic resources to one person. Because love is a worldwide phenomenon, and because the primary function of acts of love is to signal commitment, women are predicted to place a premium on love in the process of choosing a long-term mate. The international study on choosing a mate confrmed the importance of love across cultures. Among 18 possible characteristics, mutual attraction or love proved to be the most highly valued in a potential mate by both sexes, rated 2.87 by women and 2.81 by men (Buss et al., 1990). Nearly all women and men, from the Zulu of South Africa to urban Brazilians, gave love the top rating, indicating that it is an indispensable part of long-term mating. Another study of love in 48 nations found high levels of love in all of them (Schmitt et al., 2009). 4 WOMEN’S LONG-TERM MATiNG STRATEGiES 117 Researchers have made progress in identifying the underlying brain mechanisms involved in love (Bartels & Zeki, 2004; Fisher, Aron, & Brown, 2005). Using functional magnetic resonance imaging (fMRI) technology, researchers scanned the brains of individuals who were intensely in love while they thought about their loved one. The specifc areas of the brain that “lit up” (showed an increased blood fow, indicating changes in neural activity) centered on the caudate nucleus and the ventral tegmental areas. These areas contain cells that produce dopamine, which stimulates the reward centers of the brain, analogous to experiencing a “rush” of cocaine (Fisher, 2006). Thus, researchers are beginning to make progress in identifying the underlying brain circuits involved in the psychological state of love. Preference for Willingness to Invest in Children Another adaptive problem that women face when selecting a long-term mate is gauging men’s willingness to invest in children. This adaptive problem is important for two reasons: (1) Men sometimes seek sexual variety and so may channel their eforts toward other women (mating efort) rather than toward children (parental efort; see Chapter 6); and (2) men evaluate the likelihood that they are the actual genetic father of a child and tend to withhold investment from the child when they know or suspect that the child is not their own (La Cerra, 1994). To test the hypothesis that women have an evolved preference for men who are willing to invest in children, psychologist Peggy La Cerra constructed slide images of men in several diferent conditions: (1) a man standing alone; (2) a man interacting with an 18-month-old child, including smiling, making eye contact, and reaching for the child; (3) a man ignoring the child, who was crying; (4) a man and the child simply facing forward (neutral condition); and (5) a man vacuuming a living room rug. The same models were depicted in all conditions. After viewing these slide images, 240 women rated each image on how attractive they found the man in each slide as a date, as a sexual partner, as a marriage partner, as a friend, and as a neighbor. The rating scale ranged from −5 (very unattractive) to +5 (very attractive). First, women found the man interacting with the child positively to be more attractive as a marriage partner (average attractiveness rating, 2.75) than the same man either standing alone (2.0) or standing neutrally next to the child (2.0). Second, women found the man La Cerra (1994) found that women fnd the man interacting positively with the baby considerably more attractive, suggesting a mate preference for men who display a willingness to invest in children. Comparable photographs of women, shown either ignoring or interacting positively with a baby, produced no efect on men’s judgments of women’s attractiveness. iStock © jarenwicklund