Paternal Provisioning versus Mate-Seeking in Human Populations
by Prof. Edward M. Miller
Professor of Economics and Finance
University of New Orleans
from Personality and Individual Differences, Vol. 17, August 1994
Abstract
Introduction
Male Competition for Mating Opportunities
Hunting as a Fuction of Latitude
The Cold Climate Situation
Predictions of the Hypothesis
Using Racial Data to Test Clinal Theories
Explaining Racial Variation by Mating Competition versus Provisioning
Aggression
Dominance
Anxiety
Impulsivity
Delay of gratification
Sociability
Extraversion
Behavioral restraint
Criminal activity
Sexual restraint
Sexual behavior
Size of sex organs
Body build
Muscle characteristics
Life Span Variations
Hormonal Levels Versus Timing of Sexual Maturity
Implications for Females
The Distribution of Polygyny
New World African Origin Populations
Father Absent Societies
Testing the Theory with other Populations
Conclusions
Abstract
Paternal investment theory suggests that in cold climates males were selected for provisioning, rather than for mating success. In warm climates, where female gathering made male provisioning unessential, selection was for mating success. Male hunted meat was essential for female winter survival. Genes that encouraged mating success were selected for in warm (was cold) climates. Negroids (blacks) evolved in warm cold climates, while Caucasians (whites) and Mongoloids (Asians) evolved in colder climates. Mating is assisted by a strong sex drive, aggression, dominance, sociability, extraversion, impulsiveness, sensation seeking, and high testosterone. Provisioning is assisted by anxiety, altruism, empathy, behavioral restraint, gratification delay, and a long life span. Explanations are offered for racial differences in many personality characteristics, hormone levels, monamine oxidase levels, testosterone levels, lactase dehydrogenase metabolic paths, life spans, prostate cancer rates, hypertension, genital (penis and testes) size, vocal frequencies, liver size, muscle structure, mesomorphy, bone density, sports performance, crime rates, rape, child abuse, earnings, age at first sexual activity, AIDs, illegitimacy, divorce, marriage, and polygyny rates. Eye color correlations are discussed. Negro family structure in the Caribbean and the U.S. may reflect selection in Africa during hunter-gather times. Comparison is made with differential K theory and father absence theories.
Key words: race, climate, evolution, personality, polygyny, aggression, provisioning, mating, dominance seeking, paternal investment
Rushton (1985, 1987, 1988, 1989b, in press) and Ellis (1987) have drawn attention to the existence of many racial differences, including behavioral ones, and shown that they were frequently arranged in the order Mongoloid, Caucasoid, Negroid (or Negroid, Caucasoid, Mongoloid, depending on the trait). The differences Rushton drew attention to include twinning rates, (Negroids first, Caucasoids second, Mongoloids third), intelligence (Mongoloids first, Caucasoids second, Negroids third), various differences in aggression, dominance seeking, impulsivity, extraversion, sexual behavior, genital size (Negroids first, Caucasoids second, Mongoloids last), extent of altruism, and behavioral restraint (Mongoloids first, Caucasoids second, and Negroids last), and timing of birth, menarche, birth of first child, and death (Negroids earliest, Caucasoids second, Mongoloids last).
Rushton explains his observations by a version of r versus K selection theory. The terms r and K come from population biology, where r is a population’s maximum growth rate, and K is the environment’s carrying capacity. K selected species have been selected for success at competition with conspecifics. Species selected for fast reproduction with low ability to compete are called r selected. Rushton extends the idea to human populations. He argues that Negroids are the least K selected among human populations, Mongoloids the most K selected, and Caucasoids in between. This idea has produced considerable scientific (J. Anderson, 1991; Flynn, 1989; Leslie, 1990; Lynn, 1989; Roberts & Gabor, 1990; Silverman, 1990; Weizmann, Wiener, Wiesenthal, & Ziegler, 1990; Zuckerman, 1991; Miller, 1993) and popular controversy (Gross, 1990; Pearson, 1991, Chap. 5; Lerner, 1992, pp. 139-147), to which Rushton (1989a, 1990a, 1990b, Rushton & Ankney, 1993) has responded. Chisholm (1993) has also applied life cycle theory to humans, arguing that early experiences with the correlates of high death rates affects the allocation between mating and parenting.
This paper will propose an alternative explanation to differential K theory. Like differential K theory, it will be derived from a standard biological theory, parental investment theory. In some species, males devote more effort to seeking mating opportunities. In other species, they devote more effort to assisting their offspring. In each species, males evolve to use the strategy that most promotes their fitness. Which strategy most promotes their fitness depends on the effect of paternal investment on offspring survival and fitness, and on the opportunities for obtaining reproductively successful additional matings (Katz & Konner, 1981; Clutton-Brock, 1991). Likewise, within the same species different populations have been selected for different positions on the paternal investment versus mating effort continuum.
In humans, an especially important form of paternal investment is provisioning, bringing the mother and child food. Offspring’s benefit from provisioning depends on climate. In warm climates, females typically can gather enough food for themselves and their children. In cold climates, hunting is required to survive winter, and females typically do not hunt (other than for easily captured small game). Hence, offspring survival requires male provisioning in cold climates. Thus, cold climate males were selected to devote more efforts to provisioning, and less to seeking matings. In warm climates, such male provisioning was not essential, even if desirable. Thus, warm climate males who devoted more efforts to seeking mating opportunities, and less to provisioning, left more offspring. This theory can explain many of the known racial differences.
Paternal investment theory’s chief advantage is its specificity as to the traits populations should exhibit. It makes specific testable predictions (which are generally sustained) as to how cold-adapted populations and tropical populations should behave. In contrast, Rushton’s and Ellis’s differential K theories, after stating that Mongoloids are most K selected, and Negroids least, are very vague as to why this is. They fail to predict how other races (Malays, Australian aborigines, Polynesians, etc), or populations within the major races, should differ (J. Anderson, 1991; Miller, 1993).
To limit this paper’s length, a detailed treatment of the evidence for the racial differences discussed will not be attempted. The reader can find relevant references in Ellis (1987, p. 159) and in Rushton’s papers (especially 1987, p. 1019, 1989a, p. 9) and in Rushton’s forthcoming book (in press). The author has checked most of these. Although many of the individual studies could be improved on, the racial differences do appear to be as Rushton and Ellis depict them. Strong evidence as to whether most racial differences in behavior are of environmental or genetic origin is lacking. While cultural explanations have been proposed for many of the behavioral differences, (but not for the morphological, or biochemical ones), there is not space to discuss them here. Occasionally, when new evidence has appeared since Rushton and Ellis wrote, it will be noted.
This paper combines several generally accepted ideas from different disciplines. It accepts the evidence from human behavior genetics that most personality traits have an inherited component (for instance Eaves, Eysenck & Martin, 1989; or Bouchard, Lykken, McGue, Segal, & Tellegen, 1990, or Rushton, in press, chap. 4). From biology and population genetics, it takes natural selection. From physical anthropology, it takes the theory that humans have been separated into races long enough to have evolved somewhat different appearances, many of which can be traced to climatic differences. From sociobiology, it takes the idea that males differ in the extent to which they devote their efforts to mating versus parenting, and that basic human behavior traits evolved during the hunter-gatherer 99% of human history (Barash, 1977; E. Wilson, 1975). It extends this by arguing that cold weather hunter-gatherers evolved into Mongoloids and Caucasoids, and tropical African hunter-gatherers into Negroids, and that differences in morphological and behavioral gene frequencies can be explained by the climatic differences during hunter-gatherer times.
MALE COMPETITION FOR MATING OPPORTUNITIES
In many species, much male behavior consists of competition for females (Barash, 1977; Wilson, 1975; Trivers, 1972). This seems to be true of humans. Standard sociobiology explains differences between human male and female behavior by contrasting the male’s ability to father children by several females with the female’s inability to have children by more than one male at a time (Symons, 1979; Hrdy, 1981). Thus, men evolved to exploit any impregnation opportunities that arise, while women direct their copulations to males who are willing and able to invest in them and their children.
Thus, in discussing male behavior across species, biologists argue that males evolved a trade-off between paternal investment and mating efforts that maximizes their inclusive fitness for that environment (Draper, 1989, pp. 149-150). The argument generalizes easily to explain differences in male mating and paternal investment within a single species, such as humans.
Under some conditions males leave more descendants by devoting more energy to seeking copulations (an endeavor that often includes prestige seeking), and relatively less to provisioning their offspring. In these conditions, selection will be for such characteristics as high sex drive, aggression, a mesomorphic body build, and large testes. In these conditions females can raise children with only limited male provisioning.
In other circumstances, males are selected for extensive provisioning of their children. This normally implies less energy being devoted to seeking matings for two reasons. First, energy and resources devoted to seeking additional matings would be diverted from provisioning their mates and children, thus reducing the number of surviving children. Secondly, added matings would frequently produce children able to survive only if resources were diverted from the father’s other children. The net gain in surviving offspring would be small, or even negative. The first effect of devoting more energy to mating is to reduce total male investment in offspring, while the second spreads it among more offspring, reducing per capita investment.
I will argue that selection for male provisioning is especially common in climates with cold winters, where large game hunting is required for survival. Children of males who failed to provision would often not survive the winter.
Physical anthropologists can explain many racial variations as climatic adaptations (Baker, 1974; Coon, 1965, 1982; Krantz, 1980; Roberts, 1978). For instance, in northern latitudes, winter ultraviolet radiation intensity is low, and pale skin permits maximum vitamin D production. In low latitudes, there is a risk of excess vitamin D production and sunburn. Here dark skin is optimal (see Robins, 1991). Likewise, variations in adult ability to tolerate lactose has been interpreted as partially an adaption to low levels of ultraviolet radiation (Durham, 1991). Lynn (1991b) has contrasted the hunting required for survival in cold climates, in which Mongoloids and Caucasoids evolved, with the tropical gathering. He used this to explain the racial intelligence differences he had earlier documented (Lynn, 1991a). Here, this difference in reliance on hunting will be used to explain many other behavioral differences.
The reader will probably have little difficulty in accepting that Negroids evolved in the tropics, and Caucasoids and Mongoloids in colder climates. However, some may wonder why the Mongoloids are considered to have evolved in a colder climate than did the Caucasoids. One reason is that certain Mongoloid features (a stocky body build, and distinctive eye folds) appear to be adaptations to arctic conditions (Baker, 1974; Coon, 1965, 1982; Krantz, 1980; Roberts, 1978).
Admittedly, Europe is also cold. However, it is believed that farming started in the Middle East and then spread with the farmers’ migration into Europe. This conclusion comes from archaeology and a northwest to southeast distribution of certain genes (Menozzi, Piazza, & Cavalli-Sforza, 1978; Piazza,1993; Sokal, Oden, & Wilson, 1991). The latter suggests a population movement, rather than merely technology diffusion. The result is that some European ancestors were Middle Eastern hunter-gatherers, rather than hunter-gatherers who had evolved where the populations now live.
Hunting as a Fuction of Latitude
Richard Lee (1968, pp. 42-43) in the widely cited Man the Hunter book emphasized that most calories eaten among typical (tropical) hunter-gatherers come from gathering, leaving the impression that gathering was the primary subsistence mode for the ancestors of most peoples. However, this really held only for the well studied inhabitants of warm and tropical areas, which are the majority of surviving hunter-gatherers. He reports that “In warm-temperature, sub-tropical, and tropical latitudes, zero to thirty-nine degrees from the equator, gathering is by far the dominant mode of subsistence, appearing as primary in 25 of the 28 cases.” He found that 6 of the 8 societies whose latitude exceeded 60 degrees relied primarily on hunting. Eskimos (Inuits) are classic examples. In cool to cold temperature latitudes, from 40-59, degrees fishing was the most common subsistence mode. Temperature tells the same story, “Hunting is primary in three of the five societies in very cold climates (annual temperatures less than 32 F0.), fishing is primary in 10 of the 17 societies in cold climates (32-50 F0.): and gathering is primary in 27 of 36 societies in mild to hot climates (over 50 F0.).”
Fishing (usually male) appears to be a relatively recent development (Washburn & Lancaster, 1968, p. 294). In earlier times, before the most fertile mid-latitude lands were cleared for farming, there was probably more mid-latitude hunting. The hunting of large sea mammals from boats, so important to Eskimos, developed relatively recently.
Especially significant in the Lee tabulation (p. 43) is the absence of any predominantly gathering society above 500 latitude. Gathering is the primary way a single mother can feed her family.
The above tabulations suggest that ancestral Negroids relied on gathered vegetable material and ancestral Caucasoids and Mongoloids relied on animal matter from hunting and fishing. Supporting evidence is provided by blacks’ greater current salt retention compared to whites (Luft et al., 1991). Presumably, the lower salt content of the prehistoric low meat African diet, combined with greater sweat loss, selected for salt retention.
Another piece of evidence consistent with the environment of evolutionary adaptation for Caucasoids involving more meat eating than Negroids’ original environment is that the Negroids’ livers are smaller (Lewis, 1942, p. 276). The liver’ s function is to produce bile, which is used in fat digestion. A diet lower in fats (which are much more common in animal foods) would requires less bile for digestion.
The obvious problems of hunting while pregnant or with a small child assure that males do the hunting (for other than small and slow game) in virtually all societies (Friedl, 1975, p. 16-18; Watanabe, 1968).*(1) In climates typical of those now prevailing north of 500 a woman would have difficulty raising children without male supplied meat.
An example of women hunting small game is provided by the Twi of Melville Island, Australia (Goodale, 1971, pp. 151-169). They commonly hunt lizards, snakes, crabs, rats, and opposum and bandicoot. The last two are small animals found sleeping in logs or hollow trees, and typically are easily killed where found (i.e. without pursuit). In northern climates most such small animals would be hibernating during winter, or would be rare then.
The Hadza of Tanzania are typical tropical hunter-gatherers. Woodburn (1968, p. 52) describes the abundance of game and other food, stating, “For a Hadza to die of hunger, or even to fail to satisfy his hunger for more than a day or two, is almost inconceivable.”
Barnard and Woodburn (1988) noted that, “In all known hunter-gatherer societies, with immediate return systems, and in many but not all, hunter-gatherer societies with delayed return systems, people are almost always able to meet their nutritional needs very adequately without working long hours.” If gathering permits this, one would expect that women could adequately feed themselves and their children without male provisioning. Most tropical hunter-gatherer societies are immediate return ones.
Gardner (1972, p. 414), in describing the Paliyans, a foraging people of India, has pointed out that, “In normal times Paliyan men and women spend a bare three to four hours a day obtaining food and evidence no anxiety whatsoever about its supply.” Single individuals are able to feed themselves easily, and married couples may not feed each other. Male provisioning is clearly not necessary. Not surprisingly, with the parties not needing each other economically, “the usual situation is one of fragile, often serial, unions, terminated quickly by the offended party when conflict arises” (p. 419).
A similar impression is left by descriptions of other tropical hunter-gatherer societies. Lee & DeVore’s famous Man the Hunter is often summarized as showing that most calories come from gathering, not hunting, that most gathering is done by females, and that hunter-gatherers need spend only a relatively small part of their time in gathering. Taken together, these facts imply that a woman can feed her family with little male assistance. This suggests that males would leave more descendants by focusing their efforts on mating rather than on provisioning.*(2)
The Cold Climate Situation
Now consider a cold climate, such as prevailed where the northeastern Mongoloids (Chinese, Japanese, Koreans) are believed to have evolved. Even now these areas have cold winters. During the last ice age they were much colder. Their people’s physical features evidence numerous cold adaptations (Coon, 1965, 1982; Krantz, 1980; Roberts, 1978).
Although winter is only part of the year, it is the season animals have the greatest difficulty surviving. Most plant foods disappear (fruits, berries, edible leaves). Hunting becomes more difficult. Most animals time their reproductive cycles so there are no winter young or eggs. Eggs and young were the easiest animal protein for primitive men and women to obtain, since they were immobile or moved too slowly to escape. Many adult animals migrate (birds) or hibernate to escape the winter food shortage. Frozen ground prevents humans from digging for tubers and ice prevents or complicates fishing. Snow cover makes it hard to find fallen nuts or tuber locations, and makes walking much more difficult (Jochim, 1976, p. 138). Winter has severe weather episodes in which it is unsafe to leave shelter to hunt. Also, winter cold increases the body’s food requirements (Kleiber, 1961, p. 164, p. 239). Finally, winter is a time of short days (Torrence, 1983, emphasizes this). Thus, the very period when food is needed most is also when it is scarcest, hardest to acquire, and the time for gathering it is least.
Admittedly, there could be geographical circumstances where winter is easier. Many ungulates (such as elk) in mountainous areas winter in the lowlands. Possibly this concentration, aided by ease of tracking in snow, could make winter an easier time for survival. However, males would still be expected to be the sex that took advantage of this situation.
Jochim (1976, pp. 141-143) has estimated food consumption for German mesolithic foragers by seasons. Plants (female gatherable) are estimated to be 30% for spring and summer, 23% for fall, but zero in winter.
In northern climates a female cannot be self supporting. A female would avoid marriage to a hunter already supporting another’s family. Even if married to an excellent hunter, a second wife (receiving half of his support) would probably be poorly provisioned. Cold climates lead to environmental monogamy (Alexander, Hoogland, Howard, Noonan, and Sherman, 1979). Males evolve drives that encourage family provisioning, and discourage competing for mates.
Large game hunting often requires cooperation by groups of males. A male who doesn’t have the cooperation of others is likely to bring home less meat, and to leave fewer descendants. Variability in hunting success makes it desirable to hunt in groups that share their kills. Withdrawal of cooperation by other males is a likely penalty for trying to impregnate another’s wife. In such circumstances, the drives that lead to seeking multiple mates are selected against.
Of course, in a warm climate hunting groups are likely to exist and a philandering male may be penalized by exclusion from the group, or less cooperation. However, with opportunities for gathering and hunting small game abundant at all times, the penalty of loss of participation in the large hunts is less severe, and the selection against mating drives weaker.
Why presume that primitive hunters could not kill enough food to carry multiple females through the winter? After all, there is a lot of meat on even a single ungulate carcass. If game were abundant enough for a typical hunter to support more than one wife, population would grow. It would grow until the pressure on the game resource had reduced the yield from hunting to where one hunter could typically support only a single wife and offspring. The argument is the standard Malthusian one.
Although Man The Hunter is usually cited as showing that hunter-gatherers can feed themselves with a short work day, this appears true only of the tropical peoples discussed. That book also contains Balikci’s (1968, p. 82) discussion of the Netsilik Eskimos, who had a 10% loss of life from starvation in two years. The inland Eskimos appear to be able to support only one family per male (Alexander et al., 1979). Other northern hunter-gatherers such as the Ainu appear to have monogamy as the typical pattern, even if a few males have more than one wife.
Other descriptions of northern hunting peoples emphasize the difficulty of the life and the risks of starvation. For instance, Rogers (1972, p. 104) in his discussion of the Mistassini Cree, American sub-Arctic natives, states that, “Securing sufficient food is a constant problem and a never ending concern. Times of starvation are vividly remembered.” He also states that the gathering of vegetable foods is minimal. In such an environment a typical male could not support more than a single female. Any inadequate provisioning of her offspring could reduce his reproductive success.
Likewise, Nelson (1973) discusses how those Kutchin (north Alaska) who remembered the old ways emphasized hardships and lack of food. He reports that similar attitudes to the past are found among other Athapaskan people. Emphasis is placed on far north people because Ice Age Europe and Asia had climates similar to these peoples’ current homes (Soffer & Gamble, 1989; Scott, 1984).
Admittedly, a female without a “husband” would probably receive some meat from brothers, other family members, and other band members. In contemporary hunting bands game is usually shared with other band members (Hawkes, 1993). Even unmated females get some. Such a meat sharing system is very useful in spreading the risks of the hunt among families (Hames, 1990). In the short run, this clearly supplies some meat to women without husbands. However, it is likely that in the long run a female unattached to a male hunter would suffer. Adverse effects are most likely during occasional famines, when social traditions of sharing are likely to break down. Then band members are likely to give priority to their own offspring. One possible mechanism is through the more successful hunters joining bands with fewer non-related dependents, where their own families would be better provisioned. Thus, in time of famine, poor provisioning by a father would affect his children’s survival. The sharing systems observed among current hunters probably evolved relatively late, after an earlier system in which males gave priority to themselves and their families. While sharing may moderate regional differences in the consequences for offspring survival of male provisioning, they are unlikely to eliminate them.
Predictions of the Hypothesis
There appear to be several traits that contribute to success in mating competition. A strong sex drive would lead to more matings. A strong Coolidge effect (in which women other than regular sex partners were considered unusually attractive, see Symons, 1979, p. 209) would encourage taking additional wives, matings with other men’s wives, and rape. Efforts to mate with other men’s wives involves risks of retaliation. Thus, aggressiveness, impulsiveness, and lack of fear would contribute to leaving more descendants. If one were to have only an occasional mating with certain women, greater sperm production would lead to leaving more children. If males frequently succeeded in mating another’s wife, a high sperm production and strong sex drive would lead to leaving more offspring.
Empathy with others is not conducive to extra-marital relationships or even to taking additional wives. For instance, strong sympathy for one’s children is likely to lead to devoting spare resources to them, rather than using the resources to purchase sexual access through prostitutes, concubines, or extra wives. Likewise, if extramarital intercourse violates social mores, a strong tendency to follow social mores is not conducive to extra-marital access.
The above paternal investment theory makes a number of interesting predictions about the mating patterns of hunter-gatherer populations in warm versus cold climates.
Using Racial Data to Test Clinal Theories
Because agriculture was adopted relatively recently, differences that emerged during the hunter-gatherer stage should have survived into the ethnographic present. The above suggests that personality and behavior differences among modern populations should be correlated with the winter temperatures where they evolved. Tropical populations would be selected for greater mating efforts and lower paternal investment. In cold climates, the opposite would be true.
Ideally, analysis would use data expressed as behavioral clines drawn from data on many different populations. (A cline is a line connecting points of equal values for observations, such as lines on a weather map.) Unfortunately, such data is rare. Admittedly, some data is available from physical anthropologists’ studies of specific populations, and from the ethnographic record, coded in the Ethnographic Atlas (Murdock, 1967).
However, some population level studies do exist using such data. Wolfe and Gray (1982) found a correlation between the extent of polygyny and the height of males and females. This is easily explained by the taller males having an advantage in acquiring mates, which leads to greater selection for height in polygynous societies. Wolfe and Gray were surprized not to find clear evidence of greater sexual dimorphism is such societies, which they expected from the animal evidence. However, in humans it is known that most genes that affect height appear to affect both males and females equally (excluding the obvious exception of those carried on the X or Y chromosomes). What they regarded as a puzzling correlation between polygyny and female height is easily explained. If taller males leave more offspring, the mean height of both males and females will be raised, leaving sexual dimorphism little changed.
Wolfe and Gray used a code for the extent of father-infant proximity in the first year of life as a measure of male parental investment. They found that this correlated to a statistically significant degree with measures of polygyny (Table 8.1), and with male and female heights. Since it is unlikely that height causes differences in marriage patterns, it is more plausible that sexual selection has affected the frequencies of genes for height, and possibly for a measure of paternal investment (if that is subject to genetic variability). For these effects to have appeared, the differences in marriage patterns must have persisted long enough for natural selection to have acted. Although Wolfe and Gray did not notice this, this is the first clear evidence that sexual selection has played a role in the evolution of differences in gene frequencies among human populations.
Studies of the above type can be done for only a few variables. As Wolfe and Gray (1982, pp. 206-207) report, “Our search of the literature of cross-cultural codes revealed no codes that directly rate societies on the degree of male parental investment. This lack of codes is partly due to the fact that ethnographers rarely had a theoretical orientation in which the problem of male parental investment was of central concern and therefore rarely collected data on this problem.”
However, various physical variables do correlate with climate, among which are skin color, shape of nose, body mass and shape, etc. These highly visible surface features include the variables usually used for racial classification. It appears that Negroids evolved in the warmest climate (tropical Africa), Mongoloids in the coldest (the North China-Siberia area), and Caucasoids in intermediate climates (Europe and the Middle East). These areas are separated from each other by barriers to gene flow. The Sahara partially isolates tropical Africa. During the ice ages, the Himalayan ice sheet separated the Caucasoids from the Mongoloids.
Limits on gene flow between different areas (although not complete) permitted populations in each region to develop somewhat different morphology and behaviors. Each evolved in their respective environments so as to produce the largest numbers of descendants. Each of the major races of mankind, Negroid, Caucasoid, and Mongoloid, is itself composed of numerous separate populations. In the absence of detailed information on personality in a large number of localities around the world, the best way to look for evidence of personality varying with climate is through examining racial variability.
Rushton and Ellis have assembled considerable racial information. (These differences of course are related only to central tendencies, and any one individual need not resemble his race with regard to any single trait.) Theirs are the best summaries of non-morphological racial differences. They deserve considerable credit for assembling this data. While they interpreted their findings in differential K selection terms, their data can also be used to test the male mating effort versus paternal investment hypothesis.
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
percent of the variance accounted for by the first principal component. The second-order g also accounts for about two-thirds of the total common-factor variance in the test battery, whereas the three primary factors (verbal, performance, and memory), after g is removed, account for about one-third of the variance. It would be a rare, even freakish, collection of cognitive tests that would yield a g which, by any proper method of extraction, would be subordinate to any of the rotated first-order factors.
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