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作者：Anonymous 在 罕见奇谈 发贴, 来自 http://www.hjclub.org
Explaining Racial Variation by Mating Competition versus Provisioning
Let us start by taking the list of personality characteristics Rushton assembled (1987, p. 1019; 1988, p. 1010; 1989a, p. 9; Rushton & Bogaert, 1989) and see whether a mating effort versus parental investment framework can explain them. This can be done for most items.
Aggression
Negroids are reported (by Rushton) to be the most aggressive and Mongoloids least aggressive (Caucasoids intermediate). From a reproductive viewpoint, aggression’s benefits include leadership positions. These assist in obtaining multiple wives, and frequently provide opportunities for extramarital relationships. Aggression also produces children through rape. In warm climates, where extra wives can be self-supporting, there are clear reproductive benefits to additional wives. In cold climates, lower survival of children by the first wife will provide a partial or even complete offset.
The disadvantage to high levels of aggression is that it leads to injury or even death, either in the course of the conflict caused by the aggression, or through retaliation by victims or society. In all climates death eliminates, and disability reduces, the chances of fathering additional children. However, in cold climates, death and disability are more likely to lead to the death of existing children, while in warm climates the mother is more likely to be able to rear her children alone. This effect alone would make the optimal position on an aggression-fearfulness continuum climate dependent.
Aggression also leads to interband raiding and warfare. These increase sexual access to other bands’ females. Direct access may be through rape or wife capture. Indirectly, killing or defeating competing males reduces mating competition. Wives are later obtained by courtship or exchange.
However, additional wives only contribute to reproductive success if there is enough food to rear the resulting offspring. Where women supply their own subsistence, warfare and wife capture can produce reproductive gains. This is likely to be true in tropical areas. In cold areas, where wives must be provisioned by hunting, additional children from captured wives would divert scarce resources from other children, limiting the net gain.
A defeat in interband conflict leads to deaths and injuries. In northern climates, where the gains from success are small, and the losses large, the relatively non-aggressive will leave more descendants. In tropical climates, where the benefits are larger, selection will be for higher aggression.
While Rushton interprets aggression as a r characteristic, this is implausible. Gould (1982, p. 367) argues, “Since member of K-selected species inhabit the same niche and compete for population-limiting resources, it should not be surprising that these animals regularly fight with each other for control of those resources. Among r-selected species, on the other hand, fighting would be a waste of their most precious commodity, time.” In essence, if resources are abundant, organisms will not benefit from fighting. Destroying other individuals is only beneficial when it eliminates competitors, which is to say in K conditions. In contrast, aggression appears unambiguously useful for obtaining numerous matings, even if not for provisioning.
Dominance
Very similar comments can be made regarding dominance, where Negroids are reported to be the strongest seekers of dominance and Mongoloids least (Caucasoids intermediate). Dominance seeking leads to more mating opportunities, but also to death and injury, which reduces the survival of already born offspring, especially where male provisioning is essential. If the extra wives that dominance and prestige provide cannot be supported, the ability to attract them gives little reproductive benefit.
Anxiety
Mongoloids are reported to be the most anxious, and Negroids least (with Caucasoids in between). This is closely related to dominance seeking and aggression, in that high anxiety deters dominance seeking and aggression. The more prone an individual is to anxiety, the less likely he is to seek additional matings beyond his first wife. It is usually not in the wife’s reproductive interest for him to either take additional wives, or to seek extramarital relationships. She can be expected to have evolved to threaten retaliation, and occasionally retaliate by leaving, attacking the offending male, or enlisting the aid of her relatives or society against him. Conducting an affair with another man’s wife, or an unmarried chaste female, or rape, all involve risk taking. Thus, where the optimal male strategy is to devote less efforts to mating than to provisioning existing children, high anxiety is selected for .
There are additional reasons for selection for high anxiety in cold climates. One strategy for surviving the winter is food storage (see Miller, 1991). Food storage is practiced only (with exceptions) in societies whose growing seasons are less than about 200 days (Binford, 1980). Anxiety about food supply encourages storage, and discourages their too rapid consumption. Where storage makes a difference, high anxiety is selected for.
Coon’s descriptions (1971, p. 26-39) of hunter-gatherer housing shows that simple domed houses and lean-tos are used by southern people, while igloos, plank houses, and pit houses are used further north. Pit houses, roofed holes, are common among northern hunters because they protect well against intense cold. Houses in snowy areas can collapse with a heavy snowfall, and cause loss of life, as well as leaving the inhabitants exposed to the cold. Collapse of a tropical conical hut, or lean to, is only an inconvenience. Anxiety would appear to encourage the construction of houses with adequate safety margins, and possibly an early start to such construction. Thus, anxiety would appear to promote reproductive success more in areas with snow than in tropical areas.
Anxiety about being caught in a freezing storm, or away from a warm campfire overnight is likely to promote survival in cold climates. Thus, stronger cold climates selection for anxiety is predicted. (Nelson [1969] mentions the caution and absence of thrill seeking in Eskimos).
Impulsivity
Frequently, short term pleasures can be obtained by acting, but acting requires risking adverse consequences. One who frequently takes advantage of short term opportunities displays impulsivity. Those with high anxiety levels are less likely to seek immediate pleasures. Thus, it is not surprising that the ordering on impulsivity, Negroids highest, Mongoloids lowest (Caucasoids in between), is opposite to the ordering on anxiety.
In particular, males frequently have the opportunity to father children through extramarital relationships or rape. High impulsivity individuals would be expected to more often act on these opportunities than would low impulsivity individuals. Thus, impulsivity would be selected for where a high mating effort contributed to fitness.
Delay of gratification
Closely related to impulsivity is the ability to delay gratification. Mischel (1958, 1961c, 1971, p. 127) found a racial difference in preference for delayed gratification. Trinidad Indians (i.e. India origin) children would wait longer for a reward than Negro children, although he interpreted this as reflecting the greater absence of fathers among the Negro children. As is common in Negroid populations (see below), many of the Negroes lacked a father in the home, while few Indians lacked a father in the home. Cultural factors probably also play a role, since Grenada Negroes were similar to Trinidad Indians (Mischel, 1961c). Delay of gratification was less in a Trinidad industrial school for juvenile deliquents than in an ordinary Trinidad school, supporting the theory that difficulty in deferring gratification (such as choosing the immediate gratification obtainable from stealing, risking a future punishment) contributes to criminal activity (Mischel, 1961a). Gratification delay in Trinidad Negroes was found to be positively related to Harris’s Social Responsibility Scale, which conceptualized responsibility “as a composite of attitude elements reflecting behavior classifiable as reliable, accountable, loyal, or doing an effective job” (Mischel, 1961a, b). Interestingly, the Trinidad Negroes scored much lower than a similar aged (presumably predominantly white) US group, which Mischel (1961a, p. 6) notes is “fully consistent with anthropological observations.”
It is not known how heritable the ability to defer gratification is, although most personality variables appear to have a significant degree of heritability. However, in one experiment, using Barbadian Negroes in the Cambridge area, the mother’s delay of gratification (choice of large bottle of instant coffee in a week or a small bottle now) was found to be correlated with the child’s violating or not violating a prohibition in a temptation situation (Mischel & Gilligan, 1964, p. 412). This suggests both behaviors are reflecting a heritable trait.
Difficulty in delaying gratification and impulsivity makes provisioning more difficult. Provisioning requires suppressing the desire to eat in order to bring food back to the family. In warm climates, not eating food when available would merely deny the male forager the nutrition required to compete with other males, since his children will normally be fed in any case.
Also, a food storage strategy for surviving the winter requires deferring gratification. The impulse to immediately eat available food must be resisted to store it, and later the impulse to eat the stores must be resisted in order to retain them for later use. Survival through the winter may require not only storing food, but also storing fuel, making clothing, and building shelters. These activities require resisting impulses to divert energy to activities with shorter term returns (gathering non-storable food, drinking, or even flirting). Thus, there are other reasons why seeking immediate gratification and impulsivity would be selected against in cold climates.
Banfield (1974) has proposed that seeking immediate gratification among the U. S. inner city poor (who tend to be Negroids) explains much of their poverty. While he carefully denies believing in genetic differences (like other writers of the time), it is plausible that this trait, like most personality traits, has a genetic component. Furthermore, tropical environments, such as that of Africa, are ones where hunter-gatherer populations are described by Woodburn (1980) as “immediate gratification” ones. He has described how for the Hadza of Tanzania, food is available in the bush at any time, and that as a result there is little need to plan ahead or to defer gratification. Thus, it is plausible that the immediate gratification behaviors that Banfield blames for so many inner city problems may be a continuation of tropical hunter-gatherer behavior.
Sociability
Sociability assists in learning of, and exploiting, mating opportunities. However, time spent socializing reduces the time available for gathering food and for other parental investments. Sociability often involves remaining near the camp where others are located, while provisioning requires leaving to forage. Thus, selection for provisioning will reduce sociability.
It should be noted that if sociability leads to talking it would be selected against in northern climates, where quiet is required for hunting.
Extraversion
Extraversion represents a combination of impulsivity and sociability (Eysenck & Eysenck, 1985). Thus, extraversion will be selected for where selection for seeking copulations occurs, and be selected against in other areas. Thus, it is not surprising that Negroids rank highest in extraversion, and Mongoloids rank lowest, with Caucasoids in between.
Behavioral restraint
Rushton (1988, p. 1013) combined many of these characteristics and described them in terms of behavioral restraint, with Mongoloids being highest in behavior restraint, and Negroids being lowest (Caucasoids intermediate). Behavioral restraint is not conducive to males seeking mating opportunities, but is conducive to making high paternal investment, which frequently requires resisting immediate gratification opportunities.
Criminal activity
Criminal activity is closely related to behavior restraint, for which the evidence is that Negroids are highest, Mongoloids lowest, and Caucasoids in between (for documentation see Wilson & Herrnstein, 1985; Ellis, 1988, p. 532; Jaynes & Williams, 1989, chap. 9; Rushton, 1990a). Paternal investment theory would explain high crime rates as resulting from high aggressivity and low empathy, altruism, and rule following behavior, traits that contributed to tropical reproductive success. A contributing factor is that the racial ordering for intelligence (Mongoloids first, Caucasoids next, and Negroids last [Jensen, 1987 on Negroids; see Rushton, in press, for other references]) is opposite to those for crime, and criminal behavior is known to be more common among the less intelligent. Intelligence differences have been offered as explaining the racial differences in crime (Gordon, 1987).
If those selected for mating effort have higher levels of aggression, lower behavioral restraint, and higher sex drives, it would be predicted that rape rates would be higher. They are known to be higher in Negroids than in Caucasoids (Brownmiller, 1975, pp. 213-216; Ellis, 1989, p. 94).
Child abuse is another form of crime. Abusing a child is the opposite of investing in it. If cold climate fathers were selected for paternal investment, their descendants should commit less child abuse. Caucasoids do have lower child abuse rates than Negroids (Ellis, 1987, p. 159), and Mongoloids the lowest (Ellis 1993, p. 171) .
Sexual restraint
The form of behavioral restraint most sensitive to natural selection is sexual restraint. With regard to a wide range of sex related variables, including marital instability, Rushton (1988) and Rushton & Bogaert (1987) show that Mongoloids are the most sexually restrained, and Negroids least, with Caucasoids intermediate. Sexual restraint is the ability to resist opportunities for copulation. Males that devote their energies to paternal investment have less energy left for seeking additional matings.
Two mechanisms could produce greater sexual restraint. The sex drives (including those for seeking variety in partners) could be weaker, or the inhibitions to sexual activity could be greater. That populations exhibiting greater sexual restraint are also more restrained in other ways suggests that part of the explanation is the greater inhibition (discussed above).
However, populations may also differ in the strength of sex drives. Selection for a stronger sex drive (and for a stronger desire for variety in partners) appears a more efficient mechanism for increasing mating effort than merely selection for less restraint. Generalized mechanisms, such as changing anxiety levels, might prove counterproductive in non-sexual spheres. For instance, less anxiety might encourage taking excessive hunting risks.
Simpson and Gangestad (1991) show that the strength of the desire for numerous sexual partners (what they call sociosexuality) varies independently of the strength of the desire for frequent sex. It is very plausible that both are genetically influenced. They (Gangestad & Simpson, 1990; Simpson & Gangestad, 1991) present evidence that sociosexuality varies with personality dimensions that have been shown to possess heritable components. Gangestad and Simpson (1990) argue that seeking separate partners, versus making a commitment to one partner represent different reproductive strategies, but fail to consider the possibility that the equilibrium percentage of individuals following the different strategies may vary with the environment (and hence with race).
A genetic influence on the drive for sexual variety is also suggested by the greater male desire for variety. This is probably caused by the effects of testosterone (or another sex related hormone) on some part of the brain. Genetically controlled variability in the number of receptors or the level of hormones could produce variability in the strength of the desire for sexual variety across populations.
Sexual behavior
Rushton and Bogaert (1987) document differences in sexual behavior. Besides a literature review, they reanalyzed the Kinsey data on sexual behavior in American whites and blacks. This showed greater sexual activity in blacks than in whites. For instance, the black frequency for coitus in their first marriage was 3.83 times per week for those aged 21-25 versus 3.11 for similar whites. The more frequent intercourse within marriage suggests differences in sex drive, rather than in a generalized restraint (which should not affect the frequency of marital relations). Measures of the extent and frequency of extra-marital sexual activity (p. 542) showed more activity outside of marriage among blacks than among whites, with all reported measures being statistically significant at the .001 level. Most black working class females believe that a wife should expect running around (Staples & Johnson, 1993, pp. 156-157). “. . .Black females have their first full sexual intercourse some years earlier than the typical White female.” (Staples & Johnson, 1993, p. 77). Differences in either sex drive or in social restraint could explain these differences.
Since age at first intercourse (Martin, Eaves, & Eysenck, 1977), and age at first date, marriage, and first and second child appears to be genetically influenced (Mealey & Segal, 1993), it appears appropriate to consider hypotheses that population differences in sexual behavior are also genetically influenced.
Differences in sexual restraint and in the number of sexual partners predict racial differences in sexually transmitted diseases. Such differences exist in the distribution of AIDS (Rushton and Bogaert, 1989). They had earlier been reported for syphilis, where the negro rate (often approximated by the rate for non-whites) is a multiple of the white rate, both in civilians and in the military (Aral & Holmes, 1984, p. 130; Berg, 1984, p. 93; Lewis, 1942, p. 158). The reported gonorrhea rate is 21 times as high in blacks as in whites, although part of this difference may reflect better reporting from the public clinics frequented by blacks (Aral & Holmes, 1990, p. 22). For the common herpes simplex virus -2, the antibodies at ages 60-74 are found in over 80% of black females versus slightly over 20% of the white females (Aral & Holmes, 1990, p. 27). Pelvic inflammatory disease (caused by the spread of gonorrhea and/or chlamydia to the upper reproductive structures of women) is currently a major cause of female infertility in parts of Africa.
The most plausible proximate explanation for racial differences in sex drives is the possibility discussed below of differences in testosterone levels at the relevant ages. Testosterone promotes male sexual activity (Kemper, 1990, pp. 38-46).
Size of sex organs
One consequence of higher levels of puberty causing hormones could be greater development of the sex organs. Rushton and Bogaert (1987) use the Kinsey data to document longer penises and greater circumference of penises in blacks than in whites. From other sources they find Mongoloids to have shorter penises than Caucasoids. One condom manufacturer provides for larger size condoms for Africa than for other areas, and the smallest size for Asia (Wong, 1991). Mongoloids have smaller testes than Caucasoids (Short, 1984; Diamond, 1986).
It would be desirable to have good quality measurements of Negroid testes size, because the theory that they have been selected for high mating effort would predict larger testes in order to win at sperm competition. High levels of polygyny, and accompanying sperm competition, would select for large testes and high sperm production, especially allowing for the tendency for the largest number of wives to occur late in life. Among the large apes, the species that have multimale mating systems (notably the chimpanzee) have larger testes (Short, 1981; Smith, 1984).
The available evidence, while not of the highest quality, does not confirm this prediction. Ajmani, Jain, & Saxena (1985) found the scrotum diameters in 320 Nigerian males to be greater than had been reported for Europeans, as predicted. An American study of adolescents (Daniel, Feinstein, Howard-Peebles & Baxley, 1982) reported “There was no significant differences in testicular volumes between black and white adolescent boys. Any possible simple correlation with race was not significant against the general variability of testicular volume.” No actual report is provided of the racial averages, leaving the possibility that some difference was found. In any case, a difference in adolescents might reflect only an earlier start to maturation among the blacks. In addition, one early autopsy study actually found lower testes weights in Negroids than in Caucasoids (Freeman, 1934).
Rushton and his colleagues explain these sex organ differences with his differential K selection hypothesis. Yet it is not obvious that larger penises (or clitorises or vaginas) lead to more offspring. Thus, they should not be interpreted as r characteristics. More plausibly, they are a mere by product of selection for high levels of sex hormones. The testosterone surge at puberty enlarges the penis, and it is plausible that higher hormonal levels would produce a larger organ. Testosterone increases the penis size of castrated rats whether applied externally or injected (Wigodsky & Greene, 1940). This makes it more plausible that racial differences in penis size reflect hormonal differences.
Body build
There are racial differences in body build. Negroes have a more masculine body build than Caucasians (Laska-Mierzejewska, 1982). The masculine body build implies strong accentuation of such masculine characteristics as a large chest, and muscular body. Negro soldiers (males) have been found in two studies to be more mesomorphic (and less endomorphic) than white soldiers, with the difference being more than one standard deviation (Damon, Bleibtreu, Elliot, & Giles, 1962, Table 2).*(3). Simply put, mesomorphy is the amount of visible muscularity. Such a body appears to have been selected for conflict with other males. Notice, this observation is evidence for paternal investment theory, since other theories do not predict that the Negroid males will be more masculine.
However, the Japanese are relatively mesomorphic, both in Hawaii (Heath, Hopkins, & Miller, 1961), and in Japan (Kraus, 1951). Thus, the extent of mesomorphy appears to be one case where Ruston’s generalization that the Caucasoids fall between the Negroids and Mongoloids breaks down.
Hudson & Holbrook (1982) found lower mean fundamental vocal frequencies in Negro males and females than others had found for whites. As is well known (and found by them), males display a lower frequency (deeper voice) than do females, and puberty deepens the male voice. This deepening is generally attributed to testosterone. The deeper Negro voice may reflect the influence of higher testosterone levels at puberty or prenatally.
Muscle characteristics
An interesting set of statistically significant differences in muscle characteristics has been found between black and white sedentary males (Ama, Simonau, Boulay, Serresse, Theriault, and Bouchard, 1986). African blacks were found to have less type I muscle fibers, more type IIa and lower activities in enzymes catalyzing reactions in phosphagenic and lactase dehydrogenase metabolic pathways. These were interpreted as likely to be inherited, and suggesting that blacks would exhibit better performance in sports requiring a short duration of exertion. Malina (1988) reviewed the literature on childhood performance, and found that blacks excelled in the dash, the standing long jump, the vertical jump, and the ball throw for distance. All of these involve a short burst of exertion. Tests with a bicycle ergocycle have shown Caucasians to have higher maximal O2 uptake, a trait adapted for endurance activities. Also, Ama, Lagasse, Bouchard, and Simonau (1990) reported better white performance (compared to black West Africans) in the last 30 seconds of a 90 second knee extension exercise, a result consistent with blacks making greater use of anaerobic energy metabolism than whites. What would have selected for racial differences in such traits?
Hunting is implausible both because Caucasoids are likely to have hunted more than Negroids, and because hunting often requires prolonged exertion to follow large animals. A likely explanation is male fighting, since fights often involve short periods of vigorous exertion (after which the opponent is hopefully defeated). Thus, Negroids appear to be selected more for fighting. This would be consistent with their more muscular body build and higher aggression. It is what would be expected if Negroids had been selected to win mating competitions.
Blacks have denser and stronger bones than whites (Himes, 1988; Pollitzer and Anderson, 1989). The disadvantage to higher density bones is higher weight (more energy required for movement) and greater need for calcium. The advantage is fewer fractures, and thus, lower mortality. The bone differences can be explained if black males engaged in more intermale conflicts, and those with stronger bones were less often injured. No other hypothesis comes immediately to mind that can explain these density differences.
Worthy (1977, chapter 2; Worthy & Markle, 1970; see also Jones & Hochner, 1973) has shown systematic differences in the sport positions blacks and whites play. He argues that where the positions require reacting properly to the opponents’ actions, blacks are more successful, while whites do better where the player initiates his own motions, as in baseball pitching, marksmanship, or in shooting a basketball free goal. He reports a Negroid relative advantage in the defensive position of an experimental game where they had to react to their opponents’ initiatives.
Worthy also correlated eye color with positions played. Dark eyed whites are overrepresented in the same positions in which blacks are overrepresented. In Worthy’s theory, eye color plays a direct role. However, eye color also varies with ethnic origin, with north Europeans having more blue eyes. This suggests an Old World cline such that ability to react to opponents’ actions increases to the south.
What circumstances would have selected for these different abilities? Survival in fights with other males would appear to depend on quick reactions to opponents’ moves. In contrast, a hunter usually stalks his prey and then chooses the time to attack. Worthy’s observations could be explained if male reproductive success in colder regions varied with hunting ability, while in the tropics it varied more with fighting ability. The eye color differences could be explained if hunting was even more important in northern Europe than in southern Europe, or if southern Europeans had interbred more with farmers of Middle Eastern origin.
Possibly relevant evidence is provided by Coleman (1980). Successful prone rifle shooters (who choose the moment of shooting) are the most introverted, while successful rapid fire pistol shooters (who have very little time to fire five shots, and have to move the pistol from target to target), are very extroverted. Apparently personality correlates with what looks like Worthy’s reactive versus non-reactive distinction. Thus, an alternative explanation for these racial differences would rely on selection for different personality traits. Since tropical climates seem to select for both quick reactions (as in fighting) and for extraversion, and cold climates for the opposite, both theories predict a similar north-south behavioral gradient.
There are other intriguing reports of correlations of eye color with behavior. Rosenberg & Kagan, (1987, 1988) and Rubin & Both (1989) report that Caucasian children that are behaviorally inhibited ( a concept related to introversion) are disproportionately blue eyed. While Rosenberg & Kagan suggest several possible biological mechanisms for this effect, a very plausible explanation is that north European children (more likely to be blue eyed) are more behaviorally inhibited than South European children (who are more likely to have brown eyes). Both eye color and behavioral inhibition are believed to be genetically influenced. If the effect is really biological with both eye color and behavior having a common cause (a pleiotropic gene effect), it would be predicted that where one sibling was blue eyed and one brown eyed, that the blue eyed one was more likely to be behaviorally inhibited. If the genes for eye color and behavior were associated merely because the ancestors of different children came from different regions, there would be no sibling correlation. Unfortunately, such a study has not yet been done.
An argument against Negroids having evolved for fighting is that they show lower pain tolerance than other races (Worthy, 1977, pp. 123-124)
Life Span Variations
Negroids have shorter lives than Caucasoids, who have shorter lives than Mongoloids. For instance, U. S. whites have a life span estimated at 76.1 years versus 69.1 years for U. S. blacks (U. S. Department of Health and Human Services, 1993). If testosterone shortens life (Hamilton, 1948), as it appears to do (shown by the shorter life span of males than females, and of normal males compared to castrated males), differential testosterone levels could explain the life span ranking.
Part of the shorter Negroid life span reflects more violent and accidental deaths, which could result directly from higher aggression. However, disease causes most of the excess deaths. As a general rule, more polygamous species have higher male death rates (relative to female rates), with much of the difference being due to degenerative diseases (Daly and Wilson, 1988, p. 142). As discussed below, Negroids appear to be more polygamous than other races.
An evolutionary biology theory of aging (Rose, 1991) holds that many genes are pleiotropic (i.e. have more than one effect). The same genes that contribute to longer life often impose disadvantages earlier in life. In the simplest case, genes which delay degeneration (perhaps through directing more energy to cell repair) also imply early life disadvantages (perhaps through leaving less energy available for mating or for lactation). A longer life can be purchased only at the expense of an earlier reproductive disadvantage. Which genes are selected for depends on whether reproductive success is facilitated more by a long life, or by early life success. This may depend on whether selection is for high paternal investment or high mating effort.
Copulation precedes childbirth, while paternal investment follows childbirth. Since death destroys a man’s ability to help his children, longevity facilitates paternal investing. Thus, if a father’s death hurts his child’s survival chances, selection for a long life will be stronger than if children can be raised without paternal assistance. Conversely, if an early death from mating competition is going to eliminate any reproductive benefits from slower degeneration later, the alleles that protect against degeneration in old age will be less beneficial (Diamond, 1992, Chapter 7, especially p. 132).
If a male does not obtain a mate when young, living longer will not add to his descendants. Suppose the number of matings determines how many descendants a man leaves. Then men are more likely to be selected for early vigor and competitive ability, even at the expense of an earlier death. Where males have been selected for mating competition, polygyny often emerges (see below). For many men to have multiple wives, others must have no wives. Thus, to perpetuate his genes in a polygynous society, a man must be ranked relatively highly by those who control sexual access. Dominance and prestige seeking would be selected for.
In a monogamous or nearly monogamous society, even undesirable men marry. Suppose genes that handicap men in mating also contribute to a longer life, and hence to greater offspring survival. Then carriers of these may leave more descendants than worse providers who are better at mating, but who still get only one wife. Genes for high testosterone probably shorten life but may contribute to mating success through stronger muscles, higher sex drive, and aggression. Many athletes shorten their lives by taking steroids (essentially synthetic testosterones) to promote competitive success.
Thus, strong male sexual competition leads to a shorter life span. This can be explai
作者：Anonymous 在 罕见奇谈 发贴, 来自 http://www.hjclub.org |
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