In non-human mammals, the family group is a heterologic system. Only three percent of mammalian species are monogamous with their mates and have both parents involved in the raising of the young. Humans rank in this three percent. Humans require both parents to ensure the survival of the young and humans, across all cultures, form pair bonds. This leads to a family group far removed from the groups of other mammals. The creation of the human family rests on three foundations: (1) the cultural phenomenon of the human family group evolved because of the instinct to protect ones genes; (2) the basis of the family group, the pair bond, is the result of the female desire to have an economically supportive mate during the developmental years of her offspring’s lives; it is also a result of the males desire to have a suitable mate for multiple children and ensure all offspring are genetically his, and (3) the extended family group is a result of the desire to pass on ones genes through any means available even if it means helping blood relatives to reproduce [kin selection], the extended family is also preferable because social and instinctual taboos prevent mating with blood relatives, thus further protecting the pair bond. The result of these instincts for modern humans is the cultural family unit, the provision of resources for offspring, and to pass on genes.
I. Culture through instinct A. Instinctual Basis a. Instinct Defined b. Instinct to protect your genes B. Culture transcended Instinct a. Define Culture b. Define Family c. How culture relates to family based on instincts II. Family groups in non-Homo Sapiens A. Family groups in non-human primates a. Differences between human and primate families b. Chimpanzee family structure c. Gibbon family structure B. Family groups in human ancestors III. The Pair Bond A. The evolution of the pair bond B. Female desire for a pair bond a. Why the female would want a pair bond b. Genetic support for the female pair bond c. The cultural basis of the female pair bond C. Male desire for a pair bond a. Why the male would want a pair bond b. Genetic support for the male pair bond c. The cultural basis of the male pair bond D. Exception to the rule, the human polygamist a. Genetic reasoning for polygamy in the male and female b. Cultural basis for polygamy c. Is polygamy in humans a result of culture or genetics? d. Is polygamy the future of humankind or the past? IV. Interactions of Extended Family A. Instincts to protect the Families Genes, altruism a. Why would anyone decide to do this? b. Why does nature allow for this action? B. The inbreeding factor in extended families a. How culturally and instinctually inbreeding is taboo b. The exceptions to the rule V. Conclusion A. Effects of the Pair bond on Natural Selection a. Why is the pair bond so ingrained in humans? b. Would humans be capable of being humans without pair bonding? B. Effects of the Family Group on Natural Selection C. Final Thoughts
I. Culture through instinct
An eternal debate exists that questions if humans are born with instincts that are comparable with the instincts possessed by other non-human species. It takes a certain amount of ego to declare humans are completely free of instincts. The term instincts is not generally used in reference to humans; because of this, humans are said to have innate predispositions although the terms are nearly interchangeable. However, the term instincts, in reference to humans, is generally defined as any innate predisposition including but not limited to the desire to eat, sleep, and reproduce. This is the definition that this paper will use.
Of all the instincts that humans share with each other arguably the most important instincts are the instinct to mate, reproduce, and protect ones offspring. The passing on and protecting of ones genes, and in turn ones offspring, is a universal trait throughout the human species. Humans are not alone in this desire to protect their genes; most other animals have this same driving urge to procreate. The instinct to procreate is the lifeblood of all species. Without a driving urge to pass on their genes most species would be incapable of long term survival; because over time, the number of individuals would diminish to a point where the gene pool is no longer diverse enough to support a healthy population. The human urge to pass on ones genes is a result of millions of years of evolution in which the ones that had the strongest urge to procreate passed on their genes far more successfully than those who did not. The success of the human species use of these instincts without having the ability to intellectually interpret them shows that a human’s innate predispositions are indeed valid (Merriman, 2000).
Culture is the manipulation of both the environment and instincts because of want rather than need. Most animals have a form of culture, although animal culture is based entirely on their instincts rather than on the modification of instincts, this primitive culture are the social dos and do nots that allow members to live together in a harmonious fashion. Other than humans, the only other animals to have routinely discovered culture in the human definition are primates. Primates are able to modify their environment with tools, and their instincts to adapt to a myriad of new situations; however, even this form of culture is extremely primitive when it compared to the human form. Human culture not only allows humans to interact with each other but it also governs the very essence of human lives. Culture is the entirety of the instinctual forces of humans channeled into institutions that allow for good and bad behavior, where those who follow the guidelines are good and the violators are bad (Titiev, 1959). Therefore, human culture is not completely separate from innate human desires or instincts; rather, it is an extension of human instincts that allows humans to manipulate their instincts to fit within whatever society, group, or environment they currently inhabit.
The term family does not contain as much controversy as instinct and culture does; although, the exact standards for determining family change, the basic definition does not. Because of what and of whom families consist has no set guidelines across all human cultures, this essay will use the most basic definition; therefore, any group whose members are related by blood to the other members of the group or are accepted as such are defined as a family. Due to cultural variations the term nuclear family refers only to one set of parents (male and a female) and their children; while the term extended family will refer to all other members of the family.
The family group is a logical offshoot of the innate desire in humans to protect ones genes. In a group, it is easier to fend off predators, find food, and raise offspring. It is also logical because the long period of gestation and post natal care required by humans and human ancestors wold ensure that many members of a single group would in some way be related. For all these reasons, and many more, the human family evolved. As with all human cultural and social groups, the family began as an instinctual group that one was born into and left upon maturation; as humans evolved the family group also evolved eventually the family became the cultural facet of human society as it is today.
II. Family groups in non-Homo Sapiens
Although humans and primates are closely related the human family structure is dissimilar to the general primate family structure. Of the parts of the human family group there are two features which are the most important to the human family group as a whole. The first of these features is the pair bond which is the basis of the family and society; the second is the altruism that exists between family members. Primates, the closest human relatives, for the most part do not participate in pair bonds as humans do. In fact, there are only five primate species where pair bonding is the normal behavior; these species include gibbons, siamangs, indris, titi monkeys, and tarsiers. This is not only important to the evolution of the family but also interesting because gibbons and humans split from a common ancestor nearly 40 million years ago, yet chimpanzees, who separated from a common ancestor with humans less than 5 million years ago, do not participate in pair bonds. This evidences that pair bonding is not an isolated event. The human pair bond evolved in humans because it was required for survival rather than always existing. Although most primates do not pair bond, nearly all primate species practice altruism (such as sharing food) with members of their group. The specific ways altruism plays out varies from species to species but generally includes an act such as one primate helping to raise another primates offspring so in the future when the benefactor has given birth to its own offspring the favor can be returned (Griffin and West, 2002). However, this is not the only way it plays out. Other examples are sharing food, banding together for protection, or one primate attempting to “rescue” another primate from a predator. For our purposes the two most similar primates to humans are the chimpanzee and the gibbon. The latter because the gibbon pair bonds for life, and the former because while the chimpanzee does not pair bond, it is the closest human relative.
In chimpanzees the community does not stay the same for long periods. The communities, rather than being a single male with several females or several breeding pairs, is open bordered from which members can leave or join almost at will. Female chimpanzees are, for the most part, more likely to leave or join the community; male chimpanzees however, stay within the same group, generally the one they are born into, for their entire lives. Chimpanzees do not have any form of pair bond; members of a group can freely mate with any other member (assuming the dominate male and the female do not object) and extra-group mating is common. Instead of genetic pair bonds, chimpanzees frequently form complex social pair bonds between males and females, with one male watching out for a particular female and her offspring. The only human-chimpanzee equivalent social group or function is the mother to child bond because unlike human males, male chimpanzees have little to no contact with except through the social pair bond with the mother (Geary, 2000). As a result chimpanzees lend credence to the fact that it is possible that the human family is a cultural rather than a solely instinctual institution.
Unlike the chimpanzee which lives in an extremely loose social family, the gibbon families consists of a pair-bonded male and female and their immature offspring. Upon maturation of the offspring, it will leave, either willingly or forcefully, at which point it forms its own pair bond. The gibbon does not live within a larger community; rather, each small family claims and protects its own territory. The pair bonded adults will protect and care for the young; the mother cares for the infants while the father cares for the juveniles (Immerman, 2003). This superficially nuclear family is one of the few examples in the natural world and is an extreme rarity in primates. In contrast to chimpanzees the gibbon family evidences that the human family is not entirely cultural and that there is evidence of instinctual families.
The human family has evolved along with the human body and mind. Although it is hard to be certain about the type of family groups human ancestors lived in, paleoanthropologists assumed that australopithecines lived in social groups, and most early theories suggested that australopithecines lived in groups much like chimpanzees. However new information suggests that because A. afarensis had less pronounced sexual dimorphisms than previously thought, that A. afarensis and other australopithecines lived in semi-monogamous groups (Reno and Meindl and McCollum, 2003). Anthropologists believe Homo habilis and early Homo erectus to be both monogamous and polygamous. However by 1 million years ago Homo erectus, with its significantly less sexual dimorphism – females were around eighty percent the size of males -, was mainly monogamous and lived in groups of bonded pairs (Wrangham and Jones and Laden and Pilbeam and Conklin-Brittain, 20003).
III. The Pair Bond**
In human ancestors, the pair bond originally formed to allow the female to raise offspring without continually putting herself and her child in danger, which in turn allowed the male to ensure the survival of his genes into the next generation. Evidence of this is as early, as 2.5 million years ago Homo habilis used a form of base camp where food was brought back to and prepared. For a pregnant or nursing female, it would be extremely dangerous to scavenge on the savannahs of Africa with a wailing infant in her arms. Because of this, the females would stay local to a central area with or without other females and gather tubers, berries, or nuts in relative safely while the males would scavenge for meat from the kills of other predators. Upon returning, the males would share the meat with their mates and the females would reciprocate with tubers (Pennisi, 1999). This model provides protection for the female and offspring as well as food and nourishment for all concerned parties. As time went by, culture took over where instinct left off and the cultural overlay of marriage was conceived (Immerman, 2003).
For the female in the pair bond the benefits are numerous, the pair bond provides food for both her and her offspring, it provides a measure of protection, and provides a climate that makes child rearing easier. The economic support for the female would allow her to spend more energy raising her offspring, and in turn, increase the chance of survival for the offspring . Furthermore, having a single permanent mate would allow her to raise a single offspring without worrying about infanticide from other males competing for her attention. There are various other reasons why a pair bond is beneficial to a female, however they are far less important than the preceding ones.
The female hominid has several genetic and physical attributes that supports the pair bond. The first of these is the lack of visible estrus. For a non-monogamous species hidden estrus holds no evolutionary advantage; in fact it is a disadvantage. However, for a monogamous species the lack of visible estrus encourages the male to stay near the female to keep other males from cuckolding him. Another advantage of a lack of estrus is that sexual activity can take place throughout a female’s life, even after menopause, this creates a lasting pair bond because the male does not need to find a younger and more receptive female to satisfy his more base urges (Merriman, 2003). Historic female choice also promoted the pair bond mentality. Female’s instincts compelled them to specifically choose males who would be both good economic providers and loyal. If the female chose a mate that did not stay and provide for her, her offspring would be less likely to survive than the offspring of a female who did pick a stable mate. This female choice not only steered female evolution to be more likely to choose loyal mates, but also steers male evolution to become loyal mates.
The cultural basis of the female pair bond is the desire for companionship, economic support and a loyal mate. Economic support in modern human populations allows for the fulfillment of the females instinct to find a supportive and loyal mate so in turn she can fulfill her desire to protect her genes. The culture of the pair bond varies from culture to culture but a successful pair bond helps a females social standing, as she is not seen as an immediate threat to the pair bonds of other females.
For the male in a pair bond, the pair bond provides him with the ability to reproduce without spending energy fighting with other males for the right to mate, it also gives him an advantage over bachelors as he has someone to help him to watch for danger and gather food. A pair bond also allows him to repeatedly impregnate the same female providing for multiple successful offspring and removes the danger of infanticide from competing males. The pair bond also allows him to be sure of his paternity therefore he does not waste energy caring and providing for non-genetic offspring.
The human male also has many traits that suggest pair bonding behavior is preferable for the species. The first of which is the minor sexual dimorphism between males and females. Although males are in general 10% larger, it is common for females to be larger than the male average. The male testes is also made for semi monogamous behavior, in chimpanzees the testes are 4 ounces, but in humans are only about 2.5 ounces (Gallup, 2004) although humans are two to three times as large by body weight, this evidences that humans are not anywhere near as promiscuous as chimpanzees, but not completely monogamous. Other evidence of the male predisposition to pair bond is the preoccupation human males have with paternity. In a group that is similar to chimpanzees or bonobos males do not worry about paternity because females mate with most males. In gorillas the alpha male gorilla is also not worried about paternity because he has the entire harem. However, in humans, the male is preoccupied with paternity because the lack of paternity would require as much energy to provide for the offspring without the benefit of passing on his genes. In human males, testosterone also decreases when they are in pair bonds, allowing them to become satisfied with the single pair bond and lessen the desire to procreate with multiple partners (Burnham and Chapman and Gray and McIntyre, 2003).
In human males, status and loyalty in a mate are the cultural drives behind male pair bond. For human males the status drive is a major part of their lives; one of the forms of thestatus drive coincides with a female’s desires in a mate. The economic stability that males strive for is also one of the most important issues for females when choosing a mate; this facet of human culture coincides exactly with the natural instincts. The second cultural drive for the male pair bond is loyalty in a marriage; across most of human kind becoming a cuckold has a major effect on the male status drive. Therefore, the male uses a cultural pair bond to ensure paternity and avoid becoming a cuckold; this cultural pair bond has the overlay of marriage.
Humans are not solely monogamous; some physical features that promote polygamous behavior in humans remain even after 2.6 million years of primarily pair bonding. Although human males are very close in size to females by weight, there is still a big enough difference that sexual dimorphism would promote occasional polygamy (Merriman, 2003). In addition in human males, the size of the testes is smaller by ratio to the body than it is in chimpanzees but not as small by ratio as gibbons, who are monogamous. This demonstrates that although humans are less promiscuous than chimpanzees they still have some physical features that promote sperm competition with other males with whom the female may have recently copulated with (Gallup, 2004). Females also have physical traits that promote occasional polygamy, in the female an orgasm takes much longer than in males; promoting copulation with multiple males in succession as is common with chimpanzees or bonobos.
Some cultural concerns also promote polygamy in humans. The most common of which is the infant survival rate. In societies where the offspring’s survival rate is low, and a single female’s offspring are not likely to survive to maturity; polygamy is more common. For this reason polygamy effects warm climates the most (Merriman, 2000). In these climates multiple wives allow for not only more children and a higher chance of the families genes being passed on, but also allows a further division of labor in hunter/gatherer communities; which in turn, provides more food for offspring increasing their chance of survival (Hayase, 1997). Another cultural pressure behind polygamy is the status drive; in most human societies, the individual culture’s form of aristocracy uses multiple wives and mistresses (including concubines, female slaves, harems) as a status symbol. Because the average member of a community cannot afford five, ten or more wives and mistresses it becomes a display of a man’s wealth and power to be able to provide for so many wives and offspring. Other cultural pressures for polygamy are in areas where a larger number of females survive to breeding age than males, or where daughters are married disproportionately to men that are more successful or higher in class for the female’s families economic gain. Other cultural reasons for women accepting or preferring polygamy includes that many women see men who are already married as “successful” and “more likely to be good husbands” than men who have not been previously married (Hertrich, 1997).
However even in human societies where polygamy is allowed and practiced, the majority of people live in monogamous pair bonds. In the Middle East, only twelve percent of marriages are polygamous and in Africa, only thirty percent of marriages are polygamous (Hayase, 1997). The majority of humans have never practiced polygamy although the majority of cultures have allowed it; some studies have shown as many as 85% out of 859 recorded cultures accept polygamy (Merriman, 2000 and Titiev, 1959). Yet, out of these 859 cultures most are small tribal groups where the elders/chiefs/aristocracy are allowed polygamous relationships but where it is extremely rare for the other members. The fact that most humans even in cultures that allow polygamy are monogamous proves that it is not a genetic trait; genetically humans are predisposed to be monogamous with occasional adulterous affairs rather than lifelong polygamists.
As human evolution has continued from our primate ancestor’s polygamy, it has slowly become less common, while monogamy has become more common. This trend has resulted in the small sexual dimorphism that humans have currently, and as time progresses the females desire to mate and procreate with males who are genetically loyal will continue the human male’s trend toward monogamy. Culturally fewer societies support polygamy because of its drain on the human breeding populations, because humans have a nearly equal birth and survival rate for males and females, thus polygamy is a losing numbers game……. Also societies as a whole as they modernize look on polygamy as being necessary in the past where a larger labor forces were needed in families and more offspring died before maturity, but are no longer needed in modernizing societies where large families are a liability.
IV. Interactions of Extended Family
The desire to protect the family’s genes (also know as kin selection) is as important to the human species as is the instinct to protect ones own genes. Although the altruism aspects of putting members of the family before oneself seems like a losing arrangement for the altruist who risks his own genes, and thus does not pass on the gene for altruism. However the altruist does gain benefits. In insects like ants by helping the queen to breed a worker will on 100% of her own genes. If the same worker had her own offspring the worker could only pass along 50% of her genes (Griffin and West, 2002). In more complex species, altruism is a favor system; by helping a relative to raise their young, build their house, or hunt the altruist can later expect that the family member will return the favor. However, even if the altruist dies before the favor is repaid it helped to ensure the survival of the relative’s offspring and in turn a portion of the altruist’s genes (Griffin and West, 2002). This ensures that a portion of the altruist genes continue into later generations and satisfies the altruists urge to protect their own genes at the same time it satisfies their altruistic tendencies. Although this form of altruism is present in most social groups, it is most effective in family groups where the members are born into their role and the dominant member and hierarchical structure is firmly in place, which replaces the waste of an altruists efforts because of infanticide or challenges to the hierarchy.
Evolution favors the altruist, even though altruism puts the altruist at a disadvantage. By helping to ensure the survival of multiple members of the family’s group the altruist is helping to increase the numbers of members in the group. This increase in populations allow for more altruists to be born and in turn more helpers to help increase the overall population of the group. Even if a altruist is killed, the population of the group still increases enough that the family group as a whole benefits.
In human cultures one of the most universal rules is avoidance of inbreeding with relatives. Although each society decides how close the members can be differently and in many societies there are exceptions to the rules, the rule is still universal (Fox, 1972)vi. Inbreeding within families would be dangerous to the stability of the pair bond and the family group as a whole. Inbreeding would create a situation in families were it would put mothers in direct competition with daughters and father in competition with sons, this instability could lead infanticide in an attempt to ensure dominance. Because of this, individuals with the desire to replace the original member of the pair bond with offspring would be at a disadvantage to family groups that did not have this desire and in turn would not be able to compete effectively with the population at large. Instinctually because of this “anti-incest” gene in a large portion of the human species, incest is not an issue because the members of the family are just not sexually attractive to them. The reasoning behind this is that the human instincts lead them to find faces that are similar in appearance to be trustworthier, but also consider them less attractive than faces that are different (DeBruine, 2002). This has the double effect that humans prefer to mate with people that do not look like them and in turn spread their genes further and to keep relatives from finding each other sexually attractive.
Historically human societies have had exceptions to the taboo for incest. Generally, these exceptions were for royalty or the “divine” rulers, in ancient Maya and Egypt the leaders were expected to marry their siblings to keep the “divine” lineage genetically pure from outsiders. Incest was also allowed in farming communities in the remote parts of china, where property was passed along a matriarchal line to help to keep goods in the family when necessary (Lumsden and Wilson, 1980). Both of these forms of exceptions are to keep the family’s status as a whole in balance, culturally and instinctually the desire to protect the family’s genes and status outweighed the instinctual desire to avoid incest.
The desire to protect the family genes ties in with incest avoidance by minimizing the parent offspring competition and the resulting violence and possible death. In a significant portion of human societies brother/sister and parent/offspring pairings are forbidden except in special circumstances, but most human societies encourage first cousin marriages (Lumsden and Wilson, 1980). The first cousin marriages helps to reinforce the family ties by opposite ends of the families genes and to ensure that while the families genes are staying strongly in family they are also mixing with non-related genes. This provides for instinctually and culturally for both incest avoidance and protection of the families genes in a single bonding.
The pair bond has been a large part of all human societies and species, for over 1.8 million years; throughout this time, the pair bond has evolved to become the foundation of most human societies. The pair bond over time has been breed into all humans, this instinctual desire for a pair bond is followed by a physical desire and reward system for the pair bond, which in turn, has been followed by a cultural desire for a pair bond. The reason for this breeding is the human requirement for long term care beyond gestation, without a desire to pair bond in either the female or the male their offspring would be less likely to survive until breeding age. Therefore, over time, the majority of offspring born would be born of pair bonded couples that would be able to support their offspring for the required ten or more years.
Because of the same human gestation and care periods that drove the evolution of the original pair bond, it also created a scenario were the human species could not have evolved to the point it is currently without it (Pedersen, 2004). Without the pair bond, the care of offspring would require a group effort like that of chimpanzees, however in chimpanzees constant internal strife within groups ensures that the dominant male sires a large portion of the offspring, not necessarily the most intelligent. In early humans intelligence allowed them to survive on the savannahs of Africa, human ancestors that were intelligent but not necessarily strong enough to compete were not at a disadvantage to alpha males. This allowed intelligence to determine an individuals breeding possibilities and consequently allowed the pair bond to be used as a way to allow not just the strongest individuals to breed but the most intelligent.
Culturally the extended family is universal, although slightly modified for each culture, whether it is the family-reunion-every-five-years style that is prevalent in the western family or the family of some nomadic tribes where the entire family stays together from birth to death. The family has been breed into humans just as the pair bond was. Family groups allow a group of individuals to live together and support each other without the conflict and hierarchical challenges that non-related groups would face. Even in modern cultures the family provides much support and assistance at far less economic and energy cost than the same help from a non-relative. The family also provides a measure of emotional stability and protection that cannot be afforded by people who do not share the same strong emotional bonds than most families do.
The desire or instinct to protect ones genes, is a powerful force in both human evolution and human culture, because of this desire the majority of cultures support both monogamy and supportive family groups. This allowed human and human ancestors to advance through the millennia from the Australopithecus to a point where they now are the dominant species. The instinct to protect ones genes promoted the pair bond and the family group, and consequently the culture that surrounds these institutions is also a result of the innate desire to protect ones genes. Although humans may still practice polygamy or may be genetically promiscuous at times, the future of human evolution lies in the trends human evolution has followed for millennia: permanent pair bonds, and strong family groups. The human family has slowly changed over the millennia from its creation as an instinct to survive, to the cultural institution it is today, but as all societies base their cultural around the family, it seems likely it will not be changing very much in the next few millennia.
Burnham T.C., Chapman, J. Flynn, Gray, P.B., McIntyre, M.H. “Men in committed, romantic Relationships have lower testosterone,” Hormones and Behavior 44, no. 2, (2003): 119-122
DeBruine, Lisa. “Facial resemblance enhances trust,” Proceedings: Biological Sciences 269, No. 1498, (2002): 1307-1312
Fox, Robin, “Alliance and constraint: Sexual selection in the evolution of human kinship systems,” in Sexual Selection and the descent of man, ed. B. Campbell (Chicago: Aldine Atherton, 1972), pp. 282-311
Gallup, Gordon G. “Semen Displacement as a Sperm Competition Strategy in Humans,” Evolutionary Psychology 2 (2004): 12 – 23
Geary, David. “Evolution and Proximate Expression of Human Paternal Investment,” Psychological Bulletin 126, no. 1 (2000): 55 – 77
Griffin, Ashleigh and West, Stuart. “Kin Selection: fact and fiction,” TRENDS in Ecology & Evolution 17, no. 1 (January, 2002): 15 – 21
Hayase, Yasuko. “Factors on Polygamy in Sub-Saharan Africa: Findings Based on the Demographic and Health Surveys.” The Developing Economies, 35, no. 3 (September 1997): 293″327
Hertrich V, Pilon M. “Matrimonial changes in Africa.” Chronicles CEPED, 26, (1997): 1-3.
Immerman, Ronald. “Perspectives on human attachment (pair bonding): Eve”s unique legacy of a
canine analogue,” Evolutionary Psychology 1 (2003): 138-154
Lumsden, Charles J. and Wilson, Edward. “Gene-culture translation in the avoidance of sibling
incest,” Proc. Natl. Acad. Sci. USA 77 no. 10 (1980): 6248-6250
Merriman, William. “The Evolution of the Human Family,” 2000,
Pedersen, Cort. “How Love Evolved from Sex and Gave Birth to Intelligence and Human Nature” Journal of Bioeconomics. 6, no. 1 (2004): 39 – 63
Pennisi, Elizabeth “Did Cooked Tubers Spur the Evolution of Big Brains?” Science. 283, no. 5410 (1999): 2004 – 2005 Reno, P, Meindl R, McCollum M, and Lovejoy C. “Sexual dimorphism in Australopithecus Afarensis was similar to that of modern humans,” The National Academy of Sciences 100, no. 16 (2003): 94049409.
Titiev, Mischa. 1959. Introduction to Cultural Anthropology. New York: Holt, Rinehart and Winston. Pp. 261 ” 286.
Wrangham RW, Jones JH, Laden G, Pilbeam D, Conklin-Brittain N. “The Raw and the Stolen. Cooking and the Ecology of Human Origins.” Curr Anthropology. 40, no.5 (2003): 567-594.
Boesch, Christopher and Tomasello, Michael. “Chimpanzee and Human Cultures,”Current Anthropology 39, no. 5, (1998): 591-
Gabora, Liane. “The Origin and Evolution of Culture and Creativity,” Journal of Memetics ” Evolutionary Models of Information Transmission 1, no. 1 (1997): 29-57
Epstein, Marcia. “Future Perfect: “Cultural Evolution” as Intercultural Education,” History of Intellectual Culture 1, no. 1 (2001),
Hemelrijk, Charlotte. “Cooperation without genes, games or cognition.” In 4th European Conference on Artificial Life, ed. P. Husbands & I. Harvey (Cambridge MA: MIT-Press, 2004), 511-520.
Hublin, Jean-Jacques, “The Quest for Adam,” Archaeology, July/August 1999, 26 ” 35
Miller, G. F. “How mate choice shaped human nature: A review of sexual selection and human evolution,” in Handbook of evolutionary psychology: Ideas, issues, and applications, Eds. C. Crawford & D. Krebs, (Lawrence Erlbaum, 1998), pp. 87-130.
Plavcan, J. Michael, van Schaik, Carel P. “Intrasexual competition and body weight dimorphism in anthropoid primates,” American Journal of Physical Anthropology 103, no. 1, (1997): 37-68
Schradin, Reeder, Mendoza, and Anzenberger. “Evolution and Proximate Expression of Human Paternal Investment,” Journal of Comparative Psychology 117, no. 2 (2003): 166-175
Schuiling GA. “The benefit and the doubt: why monogamy?,” Journal of Psychosom Obstet Gynaecol. 24 no. 1, (2003): 55-61.
Sussman, Robert. “Exploring Our Basic Human Nature”, AnthroNotes 1, no. 1 (1997): 29 ” 57